[PATCH v2 13/21] x86/xen: split off mmu_pv.c

From: Vitaly Kuznetsov
Date: Thu Mar 02 2017 - 13:06:11 EST

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Basically, mmu.c is renamed to mmu_pv.c and some code moved out to common
mmu.c.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
arch/x86/xen/Makefile | 4 +-
arch/x86/xen/mmu.c | 2702 +------------------------------------------------
arch/x86/xen/mmu_pv.c | 2635 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 2674 insertions(+), 2667 deletions(-)
create mode 100644 arch/x86/xen/mmu_pv.c

diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 6a95a8b..8da1ca9 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -8,12 +8,12 @@ endif
# Make sure early boot has no stackprotector
nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_enlighten_pv.o := $(nostackp)
-CFLAGS_mmu.o := $(nostackp)
+CFLAGS_mmu_pv.o := $(nostackp)

obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \
time.o xen-asm.o xen-asm_$(BITS).o \
grant-table.o suspend.o platform-pci-unplug.o \
- p2m.o apic.o pmu.o enlighten_pv.o
+ p2m.o apic.o pmu.o enlighten_pv.o mmu_pv.o

obj-$(CONFIG_XEN_PVHVM) += enlighten_hvm.o mmu_hvm.o
obj-$(CONFIG_XEN_PVH) += enlighten_pvh.o
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 4dfcb06..5e375a5 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1,2693 +1,66 @@
-/*
- * Xen mmu operations
- *
- * This file contains the various mmu fetch and update operations.
- * The most important job they must perform is the mapping between the
- * domain's pfn and the overall machine mfns.
- *
- * Xen allows guests to directly update the pagetable, in a controlled
- * fashion. In other words, the guest modifies the same pagetable
- * that the CPU actually uses, which eliminates the overhead of having
- * a separate shadow pagetable.
- *
- * In order to allow this, it falls on the guest domain to map its
- * notion of a "physical" pfn - which is just a domain-local linear
- * address - into a real "machine address" which the CPU's MMU can
- * use.
- *
- * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
- * inserted directly into the pagetable. When creating a new
- * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
- * when reading the content back with __(pgd|pmd|pte)_val, it converts
- * the mfn back into a pfn.
- *
- * The other constraint is that all pages which make up a pagetable
- * must be mapped read-only in the guest. This prevents uncontrolled
- * guest updates to the pagetable. Xen strictly enforces this, and
- * will disallow any pagetable update which will end up mapping a
- * pagetable page RW, and will disallow using any writable page as a
- * pagetable.
- *
- * Naively, when loading %cr3 with the base of a new pagetable, Xen
- * would need to validate the whole pagetable before going on.
- * Naturally, this is quite slow. The solution is to "pin" a
- * pagetable, which enforces all the constraints on the pagetable even
- * when it is not actively in use. This menas that Xen can be assured
- * that it is still valid when you do load it into %cr3, and doesn't
- * need to revalidate it.
- *
- * Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>, XenSource Inc, 2007
- */
-#include <linux/sched.h>
-#include <linux/highmem.h>
-#include <linux/debugfs.h>
-#include <linux/bug.h>
-#include <linux/vmalloc.h>
-#include <linux/export.h>
-#include <linux/init.h>
-#include <linux/gfp.h>
-#include <linux/memblock.h>
-#include <linux/seq_file.h>
-#include <linux/crash_dump.h>
-
-#include <trace/events/xen.h>
-
-#include <asm/pgtable.h>
-#include <asm/tlbflush.h>
-#include <asm/fixmap.h>
-#include <asm/mmu_context.h>
-#include <asm/setup.h>
-#include <asm/paravirt.h>
-#include <asm/e820.h>
-#include <asm/linkage.h>
-#include <asm/page.h>
-#include <asm/init.h>
-#include <asm/pat.h>
-#include <asm/smp.h>
-
-#include <asm/xen/hypercall.h>
-#include <asm/xen/hypervisor.h>
-
-#include <xen/xen.h>
-#include <xen/page.h>
-#include <xen/interface/xen.h>
-#include <xen/interface/hvm/hvm_op.h>
-#include <xen/interface/version.h>
-#include <xen/interface/memory.h>
-#include <xen/hvc-console.h>
-
-#include "multicalls.h"
-#include "mmu.h"
-#include "debugfs.h"
-
-/*
- * Protects atomic reservation decrease/increase against concurrent increases.
- * Also protects non-atomic updates of current_pages and balloon lists.
- */
-DEFINE_SPINLOCK(xen_reservation_lock);
-
-#ifdef CONFIG_X86_32
-/*
- * Identity map, in addition to plain kernel map. This needs to be
- * large enough to allocate page table pages to allocate the rest.
- * Each page can map 2MB.
- */
-#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
-static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
-#endif
-#ifdef CONFIG_X86_64
-/* l3 pud for userspace vsyscall mapping */
-static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
-#endif /* CONFIG_X86_64 */
-
-/*
- * Note about cr3 (pagetable base) values:
- *
- * xen_cr3 contains the current logical cr3 value; it contains the
- * last set cr3. This may not be the current effective cr3, because
- * its update may be being lazily deferred. However, a vcpu looking
- * at its own cr3 can use this value knowing that it everything will
- * be self-consistent.
- *
- * xen_current_cr3 contains the actual vcpu cr3; it is set once the
- * hypercall to set the vcpu cr3 is complete (so it may be a little
- * out of date, but it will never be set early). If one vcpu is
- * looking at another vcpu's cr3 value, it should use this variable.
- */
-DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
-DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
-
-static phys_addr_t xen_pt_base, xen_pt_size __initdata;
-
-/*
- * Just beyond the highest usermode address. STACK_TOP_MAX has a
- * redzone above it, so round it up to a PGD boundary.
- */
-#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
-
-unsigned long arbitrary_virt_to_mfn(void *vaddr)
-{
- xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
-
- return PFN_DOWN(maddr.maddr);
-}
-
-xmaddr_t arbitrary_virt_to_machine(void *vaddr)
-{
- unsigned long address = (unsigned long)vaddr;
- unsigned int level;
- pte_t *pte;
- unsigned offset;
-
- /*
- * if the PFN is in the linear mapped vaddr range, we can just use
- * the (quick) virt_to_machine() p2m lookup
- */
- if (virt_addr_valid(vaddr))
- return virt_to_machine(vaddr);
-
- /* otherwise we have to do a (slower) full page-table walk */
-
- pte = lookup_address(address, &level);
- BUG_ON(pte == NULL);
- offset = address & ~PAGE_MASK;
- return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
-}
-EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
-
-void make_lowmem_page_readonly(void *vaddr)
-{
- pte_t *pte, ptev;
- unsigned long address = (unsigned long)vaddr;
- unsigned int level;
-
- pte = lookup_address(address, &level);
- if (pte == NULL)
- return; /* vaddr missing */
-
- ptev = pte_wrprotect(*pte);
-
- if (HYPERVISOR_update_va_mapping(address, ptev, 0))
- BUG();
-}
-
-void make_lowmem_page_readwrite(void *vaddr)
-{
- pte_t *pte, ptev;
- unsigned long address = (unsigned long)vaddr;
- unsigned int level;
-
- pte = lookup_address(address, &level);
- if (pte == NULL)
- return; /* vaddr missing */
-
- ptev = pte_mkwrite(*pte);
-
- if (HYPERVISOR_update_va_mapping(address, ptev, 0))
- BUG();
-}
-
-
-static bool xen_page_pinned(void *ptr)
-{
- struct page *page = virt_to_page(ptr);
-
- return PagePinned(page);
-}
-
-void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
-{
- struct multicall_space mcs;
- struct mmu_update *u;
-
- trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
-
- mcs = xen_mc_entry(sizeof(*u));
- u = mcs.args;
-
- /* ptep might be kmapped when using 32-bit HIGHPTE */
- u->ptr = virt_to_machine(ptep).maddr;
- u->val = pte_val_ma(pteval);
-
- MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-EXPORT_SYMBOL_GPL(xen_set_domain_pte);
-
-static void xen_extend_mmu_update(const struct mmu_update *update)
-{
- struct multicall_space mcs;
- struct mmu_update *u;
-
- mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
-
- if (mcs.mc != NULL) {
- mcs.mc->args[1]++;
- } else {
- mcs = __xen_mc_entry(sizeof(*u));
- MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
- }
-
- u = mcs.args;
- *u = *update;
-}
-
-static void xen_extend_mmuext_op(const struct mmuext_op *op)
-{
- struct multicall_space mcs;
- struct mmuext_op *u;
-
- mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
-
- if (mcs.mc != NULL) {
- mcs.mc->args[1]++;
- } else {
- mcs = __xen_mc_entry(sizeof(*u));
- MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
- }
-
- u = mcs.args;
- *u = *op;
-}
-
-static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
-{
- struct mmu_update u;
-
- preempt_disable();
-
- xen_mc_batch();
-
- /* ptr may be ioremapped for 64-bit pagetable setup */
- u.ptr = arbitrary_virt_to_machine(ptr).maddr;
- u.val = pmd_val_ma(val);
- xen_extend_mmu_update(&u);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-
-static void xen_set_pmd(pmd_t *ptr, pmd_t val)
-{
- trace_xen_mmu_set_pmd(ptr, val);
-
- /* If page is not pinned, we can just update the entry
- directly */
- if (!xen_page_pinned(ptr)) {
- *ptr = val;
- return;
- }
-
- xen_set_pmd_hyper(ptr, val);
-}
-
-/*
- * Associate a virtual page frame with a given physical page frame
- * and protection flags for that frame.
- */
-void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
-{
- set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
-}
-
-static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
-{
- struct mmu_update u;
-
- if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
- return false;
-
- xen_mc_batch();
-
- u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
- u.val = pte_val_ma(pteval);
- xen_extend_mmu_update(&u);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- return true;
-}
-
-static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
-{
- if (!xen_batched_set_pte(ptep, pteval)) {
- /*
- * Could call native_set_pte() here and trap and
- * emulate the PTE write but with 32-bit guests this
- * needs two traps (one for each of the two 32-bit
- * words in the PTE) so do one hypercall directly
- * instead.
- */
- struct mmu_update u;
-
- u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
- u.val = pte_val_ma(pteval);
- HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
- }
-}
-
-static void xen_set_pte(pte_t *ptep, pte_t pteval)
-{
- trace_xen_mmu_set_pte(ptep, pteval);
- __xen_set_pte(ptep, pteval);
-}
-
-static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pteval)
-{
- trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
- __xen_set_pte(ptep, pteval);
-}
-
-pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
- unsigned long addr, pte_t *ptep)
-{
- /* Just return the pte as-is. We preserve the bits on commit */
- trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
- return *ptep;
-}
-
-void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- struct mmu_update u;
-
- trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
- xen_mc_batch();
-
- u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
- u.val = pte_val_ma(pte);
- xen_extend_mmu_update(&u);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-
-/* Assume pteval_t is equivalent to all the other *val_t types. */
-static pteval_t pte_mfn_to_pfn(pteval_t val)
-{
- if (val & _PAGE_PRESENT) {
- unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
- unsigned long pfn = mfn_to_pfn(mfn);
-
- pteval_t flags = val & PTE_FLAGS_MASK;
- if (unlikely(pfn == ~0))
- val = flags & ~_PAGE_PRESENT;
- else
- val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
- }
-
- return val;
-}
-
-static pteval_t pte_pfn_to_mfn(pteval_t val)
-{
- if (val & _PAGE_PRESENT) {
- unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
- pteval_t flags = val & PTE_FLAGS_MASK;
- unsigned long mfn;
-
- if (!xen_feature(XENFEAT_auto_translated_physmap))
- mfn = __pfn_to_mfn(pfn);
- else
- mfn = pfn;
- /*
- * If there's no mfn for the pfn, then just create an
- * empty non-present pte. Unfortunately this loses
- * information about the original pfn, so
- * pte_mfn_to_pfn is asymmetric.
- */
- if (unlikely(mfn == INVALID_P2M_ENTRY)) {
- mfn = 0;
- flags = 0;
- } else
- mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
- val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
- }
-
- return val;
-}
-
-__visible pteval_t xen_pte_val(pte_t pte)
-{
- pteval_t pteval = pte.pte;
-
- return pte_mfn_to_pfn(pteval);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
-
-__visible pgdval_t xen_pgd_val(pgd_t pgd)
-{
- return pte_mfn_to_pfn(pgd.pgd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
-
-__visible pte_t xen_make_pte(pteval_t pte)
-{
- pte = pte_pfn_to_mfn(pte);
-
- return native_make_pte(pte);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
-
-__visible pgd_t xen_make_pgd(pgdval_t pgd)
-{
- pgd = pte_pfn_to_mfn(pgd);
- return native_make_pgd(pgd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
-
-__visible pmdval_t xen_pmd_val(pmd_t pmd)
-{
- return pte_mfn_to_pfn(pmd.pmd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
-
-static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
-{
- struct mmu_update u;
-
- preempt_disable();
-
- xen_mc_batch();
-
- /* ptr may be ioremapped for 64-bit pagetable setup */
- u.ptr = arbitrary_virt_to_machine(ptr).maddr;
- u.val = pud_val_ma(val);
- xen_extend_mmu_update(&u);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-
-static void xen_set_pud(pud_t *ptr, pud_t val)
-{
- trace_xen_mmu_set_pud(ptr, val);
-
- /* If page is not pinned, we can just update the entry
- directly */
- if (!xen_page_pinned(ptr)) {
- *ptr = val;
- return;
- }
-
- xen_set_pud_hyper(ptr, val);
-}
-
-#ifdef CONFIG_X86_PAE
-static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
-{
- trace_xen_mmu_set_pte_atomic(ptep, pte);
- set_64bit((u64 *)ptep, native_pte_val(pte));
-}
-
-static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
-{
- trace_xen_mmu_pte_clear(mm, addr, ptep);
- if (!xen_batched_set_pte(ptep, native_make_pte(0)))
- native_pte_clear(mm, addr, ptep);
-}
-
-static void xen_pmd_clear(pmd_t *pmdp)
-{
- trace_xen_mmu_pmd_clear(pmdp);
- set_pmd(pmdp, __pmd(0));
-}
-#endif /* CONFIG_X86_PAE */
-
-__visible pmd_t xen_make_pmd(pmdval_t pmd)
-{
- pmd = pte_pfn_to_mfn(pmd);
- return native_make_pmd(pmd);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
-
-#if CONFIG_PGTABLE_LEVELS == 4
-__visible pudval_t xen_pud_val(pud_t pud)
-{
- return pte_mfn_to_pfn(pud.pud);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
-
-__visible pud_t xen_make_pud(pudval_t pud)
-{
- pud = pte_pfn_to_mfn(pud);
-
- return native_make_pud(pud);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
-
-static pgd_t *xen_get_user_pgd(pgd_t *pgd)
-{
- pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
- unsigned offset = pgd - pgd_page;
- pgd_t *user_ptr = NULL;
-
- if (offset < pgd_index(USER_LIMIT)) {
- struct page *page = virt_to_page(pgd_page);
- user_ptr = (pgd_t *)page->private;
- if (user_ptr)
- user_ptr += offset;
- }
-
- return user_ptr;
-}
-
-static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
-{
- struct mmu_update u;
-
- u.ptr = virt_to_machine(ptr).maddr;
- u.val = pgd_val_ma(val);
- xen_extend_mmu_update(&u);
-}
-
-/*
- * Raw hypercall-based set_pgd, intended for in early boot before
- * there's a page structure. This implies:
- * 1. The only existing pagetable is the kernel's
- * 2. It is always pinned
- * 3. It has no user pagetable attached to it
- */
-static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
-{
- preempt_disable();
-
- xen_mc_batch();
-
- __xen_set_pgd_hyper(ptr, val);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-
-static void xen_set_pgd(pgd_t *ptr, pgd_t val)
-{
- pgd_t *user_ptr = xen_get_user_pgd(ptr);
-
- trace_xen_mmu_set_pgd(ptr, user_ptr, val);
-
- /* If page is not pinned, we can just update the entry
- directly */
- if (!xen_page_pinned(ptr)) {
- *ptr = val;
- if (user_ptr) {
- WARN_ON(xen_page_pinned(user_ptr));
- *user_ptr = val;
- }
- return;
- }
-
- /* If it's pinned, then we can at least batch the kernel and
- user updates together. */
- xen_mc_batch();
-
- __xen_set_pgd_hyper(ptr, val);
- if (user_ptr)
- __xen_set_pgd_hyper(user_ptr, val);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-#endif /* CONFIG_PGTABLE_LEVELS == 4 */
-
-/*
- * (Yet another) pagetable walker. This one is intended for pinning a
- * pagetable. This means that it walks a pagetable and calls the
- * callback function on each page it finds making up the page table,
- * at every level. It walks the entire pagetable, but it only bothers
- * pinning pte pages which are below limit. In the normal case this
- * will be STACK_TOP_MAX, but at boot we need to pin up to
- * FIXADDR_TOP.
- *
- * For 32-bit the important bit is that we don't pin beyond there,
- * because then we start getting into Xen's ptes.
- *
- * For 64-bit, we must skip the Xen hole in the middle of the address
- * space, just after the big x86-64 virtual hole.
- */
-static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
- int (*func)(struct mm_struct *mm, struct page *,
- enum pt_level),
- unsigned long limit)
-{
- int flush = 0;
- unsigned hole_low, hole_high;
- unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
- unsigned pgdidx, pudidx, pmdidx;
-
- /* The limit is the last byte to be touched */
- limit--;
- BUG_ON(limit >= FIXADDR_TOP);
-
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return 0;
-
- /*
- * 64-bit has a great big hole in the middle of the address
- * space, which contains the Xen mappings. On 32-bit these
- * will end up making a zero-sized hole and so is a no-op.
- */
- hole_low = pgd_index(USER_LIMIT);
- hole_high = pgd_index(PAGE_OFFSET);
-
- pgdidx_limit = pgd_index(limit);
-#if PTRS_PER_PUD > 1
- pudidx_limit = pud_index(limit);
-#else
- pudidx_limit = 0;
-#endif
-#if PTRS_PER_PMD > 1
- pmdidx_limit = pmd_index(limit);
-#else
- pmdidx_limit = 0;
-#endif
-
- for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
- pud_t *pud;
-
- if (pgdidx >= hole_low && pgdidx < hole_high)
- continue;
-
- if (!pgd_val(pgd[pgdidx]))
- continue;
-
- pud = pud_offset(&pgd[pgdidx], 0);
-
- if (PTRS_PER_PUD > 1) /* not folded */
- flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
-
- for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
- pmd_t *pmd;
-
- if (pgdidx == pgdidx_limit &&
- pudidx > pudidx_limit)
- goto out;
-
- if (pud_none(pud[pudidx]))
- continue;
-
- pmd = pmd_offset(&pud[pudidx], 0);
-
- if (PTRS_PER_PMD > 1) /* not folded */
- flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
-
- for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
- struct page *pte;
-
- if (pgdidx == pgdidx_limit &&
- pudidx == pudidx_limit &&
- pmdidx > pmdidx_limit)
- goto out;
-
- if (pmd_none(pmd[pmdidx]))
- continue;
-
- pte = pmd_page(pmd[pmdidx]);
- flush |= (*func)(mm, pte, PT_PTE);
- }
- }
- }
-
-out:
- /* Do the top level last, so that the callbacks can use it as
- a cue to do final things like tlb flushes. */
- flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
-
- return flush;
-}
-
-static int xen_pgd_walk(struct mm_struct *mm,
- int (*func)(struct mm_struct *mm, struct page *,
- enum pt_level),
- unsigned long limit)
-{
- return __xen_pgd_walk(mm, mm->pgd, func, limit);
-}
-
-/* If we're using split pte locks, then take the page's lock and
- return a pointer to it. Otherwise return NULL. */
-static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
-{
- spinlock_t *ptl = NULL;
-
-#if USE_SPLIT_PTE_PTLOCKS
- ptl = ptlock_ptr(page);
- spin_lock_nest_lock(ptl, &mm->page_table_lock);
-#endif
-
- return ptl;
-}
-
-static void xen_pte_unlock(void *v)
-{
- spinlock_t *ptl = v;
- spin_unlock(ptl);
-}
-
-static void xen_do_pin(unsigned level, unsigned long pfn)
-{
- struct mmuext_op op;
-
- op.cmd = level;
- op.arg1.mfn = pfn_to_mfn(pfn);
-
- xen_extend_mmuext_op(&op);
-}
-
-static int xen_pin_page(struct mm_struct *mm, struct page *page,
- enum pt_level level)
-{
- unsigned pgfl = TestSetPagePinned(page);
- int flush;
-
- if (pgfl)
- flush = 0; /* already pinned */
- else if (PageHighMem(page))
- /* kmaps need flushing if we found an unpinned
- highpage */
- flush = 1;
- else {
- void *pt = lowmem_page_address(page);
- unsigned long pfn = page_to_pfn(page);
- struct multicall_space mcs = __xen_mc_entry(0);
- spinlock_t *ptl;
-
- flush = 0;
-
- /*
- * We need to hold the pagetable lock between the time
- * we make the pagetable RO and when we actually pin
- * it. If we don't, then other users may come in and
- * attempt to update the pagetable by writing it,
- * which will fail because the memory is RO but not
- * pinned, so Xen won't do the trap'n'emulate.
- *
- * If we're using split pte locks, we can't hold the
- * entire pagetable's worth of locks during the
- * traverse, because we may wrap the preempt count (8
- * bits). The solution is to mark RO and pin each PTE
- * page while holding the lock. This means the number
- * of locks we end up holding is never more than a
- * batch size (~32 entries, at present).
- *
- * If we're not using split pte locks, we needn't pin
- * the PTE pages independently, because we're
- * protected by the overall pagetable lock.
- */
- ptl = NULL;
- if (level == PT_PTE)
- ptl = xen_pte_lock(page, mm);
-
- MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
- pfn_pte(pfn, PAGE_KERNEL_RO),
- level == PT_PGD ? UVMF_TLB_FLUSH : 0);
-
- if (ptl) {
- xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
-
- /* Queue a deferred unlock for when this batch
- is completed. */
- xen_mc_callback(xen_pte_unlock, ptl);
- }
- }
-
- return flush;
-}
-
-/* This is called just after a mm has been created, but it has not
- been used yet. We need to make sure that its pagetable is all
- read-only, and can be pinned. */
-static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
-{
- trace_xen_mmu_pgd_pin(mm, pgd);
-
- xen_mc_batch();
-
- if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
- /* re-enable interrupts for flushing */
- xen_mc_issue(0);
-
- kmap_flush_unused();
-
- xen_mc_batch();
- }
-
-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
- xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
-
- if (user_pgd) {
- xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
- xen_do_pin(MMUEXT_PIN_L4_TABLE,
- PFN_DOWN(__pa(user_pgd)));
- }
- }
-#else /* CONFIG_X86_32 */
-#ifdef CONFIG_X86_PAE
- /* Need to make sure unshared kernel PMD is pinnable */
- xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
- PT_PMD);
-#endif
- xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
-#endif /* CONFIG_X86_64 */
- xen_mc_issue(0);
-}
-
-static void xen_pgd_pin(struct mm_struct *mm)
-{
- __xen_pgd_pin(mm, mm->pgd);
-}
-
-/*
- * On save, we need to pin all pagetables to make sure they get their
- * mfns turned into pfns. Search the list for any unpinned pgds and pin
- * them (unpinned pgds are not currently in use, probably because the
- * process is under construction or destruction).
- *
- * Expected to be called in stop_machine() ("equivalent to taking
- * every spinlock in the system"), so the locking doesn't really
- * matter all that much.
- */
-void xen_mm_pin_all(void)
-{
- struct page *page;
-
- spin_lock(&pgd_lock);
-
- list_for_each_entry(page, &pgd_list, lru) {
- if (!PagePinned(page)) {
- __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
- SetPageSavePinned(page);
- }
- }
-
- spin_unlock(&pgd_lock);
-}
-
-/*
- * The init_mm pagetable is really pinned as soon as its created, but
- * that's before we have page structures to store the bits. So do all
- * the book-keeping now.
- */
-static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
- enum pt_level level)
-{
- SetPagePinned(page);
- return 0;
-}
-
-static void __init xen_mark_init_mm_pinned(void)
-{
- xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
-}
-
-static int xen_unpin_page(struct mm_struct *mm, struct page *page,
- enum pt_level level)
-{
- unsigned pgfl = TestClearPagePinned(page);
-
- if (pgfl && !PageHighMem(page)) {
- void *pt = lowmem_page_address(page);
- unsigned long pfn = page_to_pfn(page);
- spinlock_t *ptl = NULL;
- struct multicall_space mcs;
-
- /*
- * Do the converse to pin_page. If we're using split
- * pte locks, we must be holding the lock for while
- * the pte page is unpinned but still RO to prevent
- * concurrent updates from seeing it in this
- * partially-pinned state.
- */
- if (level == PT_PTE) {
- ptl = xen_pte_lock(page, mm);
-
- if (ptl)
- xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
- }
-
- mcs = __xen_mc_entry(0);
-
- MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
- pfn_pte(pfn, PAGE_KERNEL),
- level == PT_PGD ? UVMF_TLB_FLUSH : 0);
-
- if (ptl) {
- /* unlock when batch completed */
- xen_mc_callback(xen_pte_unlock, ptl);
- }
- }
-
- return 0; /* never need to flush on unpin */
-}
-
-/* Release a pagetables pages back as normal RW */
-static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
-{
- trace_xen_mmu_pgd_unpin(mm, pgd);
-
- xen_mc_batch();
-
- xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
- if (user_pgd) {
- xen_do_pin(MMUEXT_UNPIN_TABLE,
- PFN_DOWN(__pa(user_pgd)));
- xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
- }
- }
-#endif
-
-#ifdef CONFIG_X86_PAE
- /* Need to make sure unshared kernel PMD is unpinned */
- xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
- PT_PMD);
-#endif
-
- __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
-
- xen_mc_issue(0);
-}
-
-static void xen_pgd_unpin(struct mm_struct *mm)
-{
- __xen_pgd_unpin(mm, mm->pgd);
-}
-
-/*
- * On resume, undo any pinning done at save, so that the rest of the
- * kernel doesn't see any unexpected pinned pagetables.
- */
-void xen_mm_unpin_all(void)
-{
- struct page *page;
-
- spin_lock(&pgd_lock);
-
- list_for_each_entry(page, &pgd_list, lru) {
- if (PageSavePinned(page)) {
- BUG_ON(!PagePinned(page));
- __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
- ClearPageSavePinned(page);
- }
- }
-
- spin_unlock(&pgd_lock);
-}
-
-static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
-{
- spin_lock(&next->page_table_lock);
- xen_pgd_pin(next);
- spin_unlock(&next->page_table_lock);
-}
-
-static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
-{
- spin_lock(&mm->page_table_lock);
- xen_pgd_pin(mm);
- spin_unlock(&mm->page_table_lock);
-}
-
-
-#ifdef CONFIG_SMP
-/* Another cpu may still have their %cr3 pointing at the pagetable, so
- we need to repoint it somewhere else before we can unpin it. */
-static void drop_other_mm_ref(void *info)
-{
- struct mm_struct *mm = info;
- struct mm_struct *active_mm;
-
- active_mm = this_cpu_read(cpu_tlbstate.active_mm);
-
- if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
- leave_mm(smp_processor_id());
-
- /* If this cpu still has a stale cr3 reference, then make sure
- it has been flushed. */
- if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
- load_cr3(swapper_pg_dir);
-}
-
-static void xen_drop_mm_ref(struct mm_struct *mm)
-{
- cpumask_var_t mask;
- unsigned cpu;
-
- if (current->active_mm == mm) {
- if (current->mm == mm)
- load_cr3(swapper_pg_dir);
- else
- leave_mm(smp_processor_id());
- }
-
- /* Get the "official" set of cpus referring to our pagetable. */
- if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
- for_each_online_cpu(cpu) {
- if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
- && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
- continue;
- smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
- }
- return;
- }
- cpumask_copy(mask, mm_cpumask(mm));
-
- /* It's possible that a vcpu may have a stale reference to our
- cr3, because its in lazy mode, and it hasn't yet flushed
- its set of pending hypercalls yet. In this case, we can
- look at its actual current cr3 value, and force it to flush
- if needed. */
- for_each_online_cpu(cpu) {
- if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
- cpumask_set_cpu(cpu, mask);
- }
-
- if (!cpumask_empty(mask))
- smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
- free_cpumask_var(mask);
-}
-#else
-static void xen_drop_mm_ref(struct mm_struct *mm)
-{
- if (current->active_mm == mm)
- load_cr3(swapper_pg_dir);
-}
-#endif
-
-/*
- * While a process runs, Xen pins its pagetables, which means that the
- * hypervisor forces it to be read-only, and it controls all updates
- * to it. This means that all pagetable updates have to go via the
- * hypervisor, which is moderately expensive.
- *
- * Since we're pulling the pagetable down, we switch to use init_mm,
- * unpin old process pagetable and mark it all read-write, which
- * allows further operations on it to be simple memory accesses.
- *
- * The only subtle point is that another CPU may be still using the
- * pagetable because of lazy tlb flushing. This means we need need to
- * switch all CPUs off this pagetable before we can unpin it.
- */
-static void xen_exit_mmap(struct mm_struct *mm)
-{
- get_cpu(); /* make sure we don't move around */
- xen_drop_mm_ref(mm);
- put_cpu();
-
- spin_lock(&mm->page_table_lock);
-
- /* pgd may not be pinned in the error exit path of execve */
- if (xen_page_pinned(mm->pgd))
- xen_pgd_unpin(mm);
-
- spin_unlock(&mm->page_table_lock);
-}
-
-static void xen_post_allocator_init(void);
-
-static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
-{
- struct mmuext_op op;
-
- op.cmd = cmd;
- op.arg1.mfn = pfn_to_mfn(pfn);
- if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
- BUG();
-}
-
-#ifdef CONFIG_X86_64
-static void __init xen_cleanhighmap(unsigned long vaddr,
- unsigned long vaddr_end)
-{
- unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
- pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
-
- /* NOTE: The loop is more greedy than the cleanup_highmap variant.
- * We include the PMD passed in on _both_ boundaries. */
- for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
- pmd++, vaddr += PMD_SIZE) {
- if (pmd_none(*pmd))
- continue;
- if (vaddr < (unsigned long) _text || vaddr > kernel_end)
- set_pmd(pmd, __pmd(0));
- }
- /* In case we did something silly, we should crash in this function
- * instead of somewhere later and be confusing. */
- xen_mc_flush();
-}
-
-/*
- * Make a page range writeable and free it.
- */
-static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
-{
- void *vaddr = __va(paddr);
- void *vaddr_end = vaddr + size;
-
- for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
- make_lowmem_page_readwrite(vaddr);
-
- memblock_free(paddr, size);
-}
-
-static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
-{
- unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
-
- if (unpin)
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
- ClearPagePinned(virt_to_page(__va(pa)));
- xen_free_ro_pages(pa, PAGE_SIZE);
-}
-
-/*
- * Since it is well isolated we can (and since it is perhaps large we should)
- * also free the page tables mapping the initial P->M table.
- */
-static void __init xen_cleanmfnmap(unsigned long vaddr)
-{
- unsigned long va = vaddr & PMD_MASK;
- unsigned long pa;
- pgd_t *pgd = pgd_offset_k(va);
- pud_t *pud_page = pud_offset(pgd, 0);
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- unsigned int i;
- bool unpin;
-
- unpin = (vaddr == 2 * PGDIR_SIZE);
- set_pgd(pgd, __pgd(0));
- do {
- pud = pud_page + pud_index(va);
- if (pud_none(*pud)) {
- va += PUD_SIZE;
- } else if (pud_large(*pud)) {
- pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
- xen_free_ro_pages(pa, PUD_SIZE);
- va += PUD_SIZE;
- } else {
- pmd = pmd_offset(pud, va);
- if (pmd_large(*pmd)) {
- pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
- xen_free_ro_pages(pa, PMD_SIZE);
- } else if (!pmd_none(*pmd)) {
- pte = pte_offset_kernel(pmd, va);
- set_pmd(pmd, __pmd(0));
- for (i = 0; i < PTRS_PER_PTE; ++i) {
- if (pte_none(pte[i]))
- break;
- pa = pte_pfn(pte[i]) << PAGE_SHIFT;
- xen_free_ro_pages(pa, PAGE_SIZE);
- }
- xen_cleanmfnmap_free_pgtbl(pte, unpin);
- }
- va += PMD_SIZE;
- if (pmd_index(va))
- continue;
- set_pud(pud, __pud(0));
- xen_cleanmfnmap_free_pgtbl(pmd, unpin);
- }
-
- } while (pud_index(va) || pmd_index(va));
- xen_cleanmfnmap_free_pgtbl(pud_page, unpin);
-}
-
-static void __init xen_pagetable_p2m_free(void)
-{
- unsigned long size;
- unsigned long addr;
-
- size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
-
- /* No memory or already called. */
- if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
- return;
-
- /* using __ka address and sticking INVALID_P2M_ENTRY! */
- memset((void *)xen_start_info->mfn_list, 0xff, size);
-
- addr = xen_start_info->mfn_list;
- /*
- * We could be in __ka space.
- * We roundup to the PMD, which means that if anybody at this stage is
- * using the __ka address of xen_start_info or
- * xen_start_info->shared_info they are in going to crash. Fortunatly
- * we have already revectored in xen_setup_kernel_pagetable and in
- * xen_setup_shared_info.
- */
- size = roundup(size, PMD_SIZE);
-
- if (addr >= __START_KERNEL_map) {
- xen_cleanhighmap(addr, addr + size);
- size = PAGE_ALIGN(xen_start_info->nr_pages *
- sizeof(unsigned long));
- memblock_free(__pa(addr), size);
- } else {
- xen_cleanmfnmap(addr);
- }
-}
-
-static void __init xen_pagetable_cleanhighmap(void)
-{
- unsigned long size;
- unsigned long addr;
-
- /* At this stage, cleanup_highmap has already cleaned __ka space
- * from _brk_limit way up to the max_pfn_mapped (which is the end of
- * the ramdisk). We continue on, erasing PMD entries that point to page
- * tables - do note that they are accessible at this stage via __va.
- * For good measure we also round up to the PMD - which means that if
- * anybody is using __ka address to the initial boot-stack - and try
- * to use it - they are going to crash. The xen_start_info has been
- * taken care of already in xen_setup_kernel_pagetable. */
- addr = xen_start_info->pt_base;
- size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
-
- xen_cleanhighmap(addr, addr + size);
- xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
-#ifdef DEBUG
- /* This is superfluous and is not necessary, but you know what
- * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
- * anything at this stage. */
- xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
-#endif
-}
-#endif
-
-static void __init xen_pagetable_p2m_setup(void)
-{
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return;
-
- xen_vmalloc_p2m_tree();
-
-#ifdef CONFIG_X86_64
- xen_pagetable_p2m_free();
-
- xen_pagetable_cleanhighmap();
-#endif
- /* And revector! Bye bye old array */
- xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
-}
-
-static void __init xen_pagetable_init(void)
-{
- paging_init();
- xen_post_allocator_init();
-
- xen_pagetable_p2m_setup();
-
- /* Allocate and initialize top and mid mfn levels for p2m structure */
- xen_build_mfn_list_list();
-
- /* Remap memory freed due to conflicts with E820 map */
- if (!xen_feature(XENFEAT_auto_translated_physmap))
- xen_remap_memory();
-
- xen_setup_shared_info();
-}
-static void xen_write_cr2(unsigned long cr2)
-{
- this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
-}
-
-static unsigned long xen_read_cr2(void)
-{
- return this_cpu_read(xen_vcpu)->arch.cr2;
-}
-
-unsigned long xen_read_cr2_direct(void)
-{
- return this_cpu_read(xen_vcpu_info.arch.cr2);
-}
-
-void xen_flush_tlb_all(void)
-{
- struct mmuext_op *op;
- struct multicall_space mcs;
-
- trace_xen_mmu_flush_tlb_all(0);
-
- preempt_disable();
-
- mcs = xen_mc_entry(sizeof(*op));
-
- op = mcs.args;
- op->cmd = MMUEXT_TLB_FLUSH_ALL;
- MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-static void xen_flush_tlb(void)
-{
- struct mmuext_op *op;
- struct multicall_space mcs;
-
- trace_xen_mmu_flush_tlb(0);
-
- preempt_disable();
-
- mcs = xen_mc_entry(sizeof(*op));
-
- op = mcs.args;
- op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
- MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-
-static void xen_flush_tlb_single(unsigned long addr)
-{
- struct mmuext_op *op;
- struct multicall_space mcs;
-
- trace_xen_mmu_flush_tlb_single(addr);
-
- preempt_disable();
-
- mcs = xen_mc_entry(sizeof(*op));
- op = mcs.args;
- op->cmd = MMUEXT_INVLPG_LOCAL;
- op->arg1.linear_addr = addr & PAGE_MASK;
- MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-
- preempt_enable();
-}
-
-static void xen_flush_tlb_others(const struct cpumask *cpus,
- struct mm_struct *mm, unsigned long start,
- unsigned long end)
-{
- struct {
- struct mmuext_op op;
-#ifdef CONFIG_SMP
- DECLARE_BITMAP(mask, num_processors);
-#else
- DECLARE_BITMAP(mask, NR_CPUS);
-#endif
- } *args;
- struct multicall_space mcs;
-
- trace_xen_mmu_flush_tlb_others(cpus, mm, start, end);
-
- if (cpumask_empty(cpus))
- return; /* nothing to do */
-
- mcs = xen_mc_entry(sizeof(*args));
- args = mcs.args;
- args->op.arg2.vcpumask = to_cpumask(args->mask);
-
- /* Remove us, and any offline CPUS. */
- cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
- cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
-
- args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
- if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
- args->op.cmd = MMUEXT_INVLPG_MULTI;
- args->op.arg1.linear_addr = start;
- }
-
- MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
-}
-
-static unsigned long xen_read_cr3(void)
-{
- return this_cpu_read(xen_cr3);
-}
-
-static void set_current_cr3(void *v)
-{
- this_cpu_write(xen_current_cr3, (unsigned long)v);
-}
-
-static void __xen_write_cr3(bool kernel, unsigned long cr3)
-{
- struct mmuext_op op;
- unsigned long mfn;
-
- trace_xen_mmu_write_cr3(kernel, cr3);
-
- if (cr3)
- mfn = pfn_to_mfn(PFN_DOWN(cr3));
- else
- mfn = 0;
-
- WARN_ON(mfn == 0 && kernel);
-
- op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
- op.arg1.mfn = mfn;
-
- xen_extend_mmuext_op(&op);
-
- if (kernel) {
- this_cpu_write(xen_cr3, cr3);
-
- /* Update xen_current_cr3 once the batch has actually
- been submitted. */
- xen_mc_callback(set_current_cr3, (void *)cr3);
- }
-}
-static void xen_write_cr3(unsigned long cr3)
-{
- BUG_ON(preemptible());
-
- xen_mc_batch(); /* disables interrupts */
-
- /* Update while interrupts are disabled, so its atomic with
- respect to ipis */
- this_cpu_write(xen_cr3, cr3);
-
- __xen_write_cr3(true, cr3);
-
-#ifdef CONFIG_X86_64
- {
- pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
- if (user_pgd)
- __xen_write_cr3(false, __pa(user_pgd));
- else
- __xen_write_cr3(false, 0);
- }
-#endif
-
- xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
-}
-
-#ifdef CONFIG_X86_64
-/*
- * At the start of the day - when Xen launches a guest, it has already
- * built pagetables for the guest. We diligently look over them
- * in xen_setup_kernel_pagetable and graft as appropriate them in the
- * init_level4_pgt and its friends. Then when we are happy we load
- * the new init_level4_pgt - and continue on.
- *
- * The generic code starts (start_kernel) and 'init_mem_mapping' sets
- * up the rest of the pagetables. When it has completed it loads the cr3.
- * N.B. that baremetal would start at 'start_kernel' (and the early
- * #PF handler would create bootstrap pagetables) - so we are running
- * with the same assumptions as what to do when write_cr3 is executed
- * at this point.
- *
- * Since there are no user-page tables at all, we have two variants
- * of xen_write_cr3 - the early bootup (this one), and the late one
- * (xen_write_cr3). The reason we have to do that is that in 64-bit
- * the Linux kernel and user-space are both in ring 3 while the
- * hypervisor is in ring 0.
- */
-static void __init xen_write_cr3_init(unsigned long cr3)
-{
- BUG_ON(preemptible());
-
- xen_mc_batch(); /* disables interrupts */
-
- /* Update while interrupts are disabled, so its atomic with
- respect to ipis */
- this_cpu_write(xen_cr3, cr3);
-
- __xen_write_cr3(true, cr3);
-
- xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
-}
-#endif
-
-static int xen_pgd_alloc(struct mm_struct *mm)
-{
- pgd_t *pgd = mm->pgd;
- int ret = 0;
-
- BUG_ON(PagePinned(virt_to_page(pgd)));
-
-#ifdef CONFIG_X86_64
- {
- struct page *page = virt_to_page(pgd);
- pgd_t *user_pgd;
-
- BUG_ON(page->private != 0);
-
- ret = -ENOMEM;
-
- user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
- page->private = (unsigned long)user_pgd;
-
- if (user_pgd != NULL) {
-#ifdef CONFIG_X86_VSYSCALL_EMULATION
- user_pgd[pgd_index(VSYSCALL_ADDR)] =
- __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
-#endif
- ret = 0;
- }
-
- BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
- }
-#endif
-
- return ret;
-}
-
-static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
-{
-#ifdef CONFIG_X86_64
- pgd_t *user_pgd = xen_get_user_pgd(pgd);
-
- if (user_pgd)
- free_page((unsigned long)user_pgd);
-#endif
-}
-
-/*
- * Init-time set_pte while constructing initial pagetables, which
- * doesn't allow RO page table pages to be remapped RW.
- *
- * If there is no MFN for this PFN then this page is initially
- * ballooned out so clear the PTE (as in decrease_reservation() in
- * drivers/xen/balloon.c).
- *
- * Many of these PTE updates are done on unpinned and writable pages
- * and doing a hypercall for these is unnecessary and expensive. At
- * this point it is not possible to tell if a page is pinned or not,
- * so always write the PTE directly and rely on Xen trapping and
- * emulating any updates as necessary.
- */
-__visible pte_t xen_make_pte_init(pteval_t pte)
-{
-#ifdef CONFIG_X86_64
- unsigned long pfn;
-
- /*
- * Pages belonging to the initial p2m list mapped outside the default
- * address range must be mapped read-only. This region contains the
- * page tables for mapping the p2m list, too, and page tables MUST be
- * mapped read-only.
- */
- pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
- if (xen_start_info->mfn_list < __START_KERNEL_map &&
- pfn >= xen_start_info->first_p2m_pfn &&
- pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
- pte &= ~_PAGE_RW;
-#endif
- pte = pte_pfn_to_mfn(pte);
- return native_make_pte(pte);
-}
-PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
-
-static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
-{
-#ifdef CONFIG_X86_32
- /* If there's an existing pte, then don't allow _PAGE_RW to be set */
- if (pte_mfn(pte) != INVALID_P2M_ENTRY
- && pte_val_ma(*ptep) & _PAGE_PRESENT)
- pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
- pte_val_ma(pte));
-#endif
- native_set_pte(ptep, pte);
-}
-
-/* Early in boot, while setting up the initial pagetable, assume
- everything is pinned. */
-static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
-{
-#ifdef CONFIG_FLATMEM
- BUG_ON(mem_map); /* should only be used early */
-#endif
- make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
- pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
-}
-
-/* Used for pmd and pud */
-static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
-{
-#ifdef CONFIG_FLATMEM
- BUG_ON(mem_map); /* should only be used early */
-#endif
- make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
-}
-
-/* Early release_pte assumes that all pts are pinned, since there's
- only init_mm and anything attached to that is pinned. */
-static void __init xen_release_pte_init(unsigned long pfn)
-{
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
- make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
-}
-
-static void __init xen_release_pmd_init(unsigned long pfn)
-{
- make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
-}
-
-static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
-{
- struct multicall_space mcs;
- struct mmuext_op *op;
-
- mcs = __xen_mc_entry(sizeof(*op));
- op = mcs.args;
- op->cmd = cmd;
- op->arg1.mfn = pfn_to_mfn(pfn);
-
- MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
-}
-
-static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
-{
- struct multicall_space mcs;
- unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
-
- mcs = __xen_mc_entry(0);
- MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
- pfn_pte(pfn, prot), 0);
-}
-
-/* This needs to make sure the new pte page is pinned iff its being
- attached to a pinned pagetable. */
-static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
- unsigned level)
-{
- bool pinned = PagePinned(virt_to_page(mm->pgd));
-
- trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
-
- if (pinned) {
- struct page *page = pfn_to_page(pfn);
-
- SetPagePinned(page);
-
- if (!PageHighMem(page)) {
- xen_mc_batch();
-
- __set_pfn_prot(pfn, PAGE_KERNEL_RO);
-
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
- __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
- } else {
- /* make sure there are no stray mappings of
- this page */
- kmap_flush_unused();
- }
- }
-}
-
-static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
-{
- xen_alloc_ptpage(mm, pfn, PT_PTE);
-}
-
-static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
-{
- xen_alloc_ptpage(mm, pfn, PT_PMD);
-}
-
-/* This should never happen until we're OK to use struct page */
-static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
-{
- struct page *page = pfn_to_page(pfn);
- bool pinned = PagePinned(page);
-
- trace_xen_mmu_release_ptpage(pfn, level, pinned);
-
- if (pinned) {
- if (!PageHighMem(page)) {
- xen_mc_batch();
-
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
- __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
-
- __set_pfn_prot(pfn, PAGE_KERNEL);
-
- xen_mc_issue(PARAVIRT_LAZY_MMU);
- }
- ClearPagePinned(page);
- }
-}
-
-static void xen_release_pte(unsigned long pfn)
-{
- xen_release_ptpage(pfn, PT_PTE);
-}
-
-static void xen_release_pmd(unsigned long pfn)
-{
- xen_release_ptpage(pfn, PT_PMD);
-}
-
-#if CONFIG_PGTABLE_LEVELS == 4
-static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
-{
- xen_alloc_ptpage(mm, pfn, PT_PUD);
-}
-
-static void xen_release_pud(unsigned long pfn)
-{
- xen_release_ptpage(pfn, PT_PUD);
-}
-#endif
-
-void __init xen_reserve_top(void)
-{
-#ifdef CONFIG_X86_32
- unsigned long top = HYPERVISOR_VIRT_START;
- struct xen_platform_parameters pp;
-
- if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
- top = pp.virt_start;
-
- reserve_top_address(-top);
-#endif /* CONFIG_X86_32 */
-}
-
-/*
- * Like __va(), but returns address in the kernel mapping (which is
- * all we have until the physical memory mapping has been set up.
- */
-static void * __init __ka(phys_addr_t paddr)
-{
-#ifdef CONFIG_X86_64
- return (void *)(paddr + __START_KERNEL_map);
-#else
- return __va(paddr);
-#endif
-}
-
-/* Convert a machine address to physical address */
-static unsigned long __init m2p(phys_addr_t maddr)
-{
- phys_addr_t paddr;
-
- maddr &= PTE_PFN_MASK;
- paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
-
- return paddr;
-}
-
-/* Convert a machine address to kernel virtual */
-static void * __init m2v(phys_addr_t maddr)
-{
- return __ka(m2p(maddr));
-}
-
-/* Set the page permissions on an identity-mapped pages */
-static void __init set_page_prot_flags(void *addr, pgprot_t prot,
- unsigned long flags)
-{
- unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
- pte_t pte = pfn_pte(pfn, prot);
-
- if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
- BUG();
-}
-static void __init set_page_prot(void *addr, pgprot_t prot)
-{
- return set_page_prot_flags(addr, prot, UVMF_NONE);
-}
-#ifdef CONFIG_X86_32
-static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
-{
- unsigned pmdidx, pteidx;
- unsigned ident_pte;
- unsigned long pfn;
-
- level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
- PAGE_SIZE);
-
- ident_pte = 0;
- pfn = 0;
- for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
- pte_t *pte_page;
-
- /* Reuse or allocate a page of ptes */
- if (pmd_present(pmd[pmdidx]))
- pte_page = m2v(pmd[pmdidx].pmd);
- else {
- /* Check for free pte pages */
- if (ident_pte == LEVEL1_IDENT_ENTRIES)
- break;
-
- pte_page = &level1_ident_pgt[ident_pte];
- ident_pte += PTRS_PER_PTE;
-
- pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
- }
-
- /* Install mappings */
- for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
- pte_t pte;
-
- if (pfn > max_pfn_mapped)
- max_pfn_mapped = pfn;
-
- if (!pte_none(pte_page[pteidx]))
- continue;
-
- pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
- pte_page[pteidx] = pte;
- }
- }
-
- for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
- set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
-
- set_page_prot(pmd, PAGE_KERNEL_RO);
-}
-#endif
-void __init xen_setup_machphys_mapping(void)
-{
- struct xen_machphys_mapping mapping;
-
- if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
- machine_to_phys_mapping = (unsigned long *)mapping.v_start;
- machine_to_phys_nr = mapping.max_mfn + 1;
- } else {
- machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
- }
-#ifdef CONFIG_X86_32
- WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
- < machine_to_phys_mapping);
-#endif
-}
-
-#ifdef CONFIG_X86_64
-static void __init convert_pfn_mfn(void *v)
-{
- pte_t *pte = v;
- int i;
-
- /* All levels are converted the same way, so just treat them
- as ptes. */
- for (i = 0; i < PTRS_PER_PTE; i++)
- pte[i] = xen_make_pte(pte[i].pte);
-}
-static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
- unsigned long addr)
-{
- if (*pt_base == PFN_DOWN(__pa(addr))) {
- set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
- clear_page((void *)addr);
- (*pt_base)++;
- }
- if (*pt_end == PFN_DOWN(__pa(addr))) {
- set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
- clear_page((void *)addr);
- (*pt_end)--;
- }
-}
-/*
- * Set up the initial kernel pagetable.
- *
- * We can construct this by grafting the Xen provided pagetable into
- * head_64.S's preconstructed pagetables. We copy the Xen L2's into
- * level2_ident_pgt, and level2_kernel_pgt. This means that only the
- * kernel has a physical mapping to start with - but that's enough to
- * get __va working. We need to fill in the rest of the physical
- * mapping once some sort of allocator has been set up.
- */
-void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
-{
- pud_t *l3;
- pmd_t *l2;
- unsigned long addr[3];
- unsigned long pt_base, pt_end;
- unsigned i;
-
- /* max_pfn_mapped is the last pfn mapped in the initial memory
- * mappings. Considering that on Xen after the kernel mappings we
- * have the mappings of some pages that don't exist in pfn space, we
- * set max_pfn_mapped to the last real pfn mapped. */
- if (xen_start_info->mfn_list < __START_KERNEL_map)
- max_pfn_mapped = xen_start_info->first_p2m_pfn;
- else
- max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
-
- pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
- pt_end = pt_base + xen_start_info->nr_pt_frames;
-
- /* Zap identity mapping */
- init_level4_pgt[0] = __pgd(0);
-
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- /* Pre-constructed entries are in pfn, so convert to mfn */
- /* L4[272] -> level3_ident_pgt
- * L4[511] -> level3_kernel_pgt */
- convert_pfn_mfn(init_level4_pgt);
-
- /* L3_i[0] -> level2_ident_pgt */
- convert_pfn_mfn(level3_ident_pgt);
- /* L3_k[510] -> level2_kernel_pgt
- * L3_k[511] -> level2_fixmap_pgt */
- convert_pfn_mfn(level3_kernel_pgt);
-
- /* L3_k[511][506] -> level1_fixmap_pgt */
- convert_pfn_mfn(level2_fixmap_pgt);
- }
- /* We get [511][511] and have Xen's version of level2_kernel_pgt */
- l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
- l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
-
- addr[0] = (unsigned long)pgd;
- addr[1] = (unsigned long)l3;
- addr[2] = (unsigned long)l2;
- /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
- * Both L4[272][0] and L4[511][510] have entries that point to the same
- * L2 (PMD) tables. Meaning that if you modify it in __va space
- * it will be also modified in the __ka space! (But if you just
- * modify the PMD table to point to other PTE's or none, then you
- * are OK - which is what cleanup_highmap does) */
- copy_page(level2_ident_pgt, l2);
- /* Graft it onto L4[511][510] */
- copy_page(level2_kernel_pgt, l2);
-
- /* Copy the initial P->M table mappings if necessary. */
- i = pgd_index(xen_start_info->mfn_list);
- if (i && i < pgd_index(__START_KERNEL_map))
- init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
-
- if (!xen_feature(XENFEAT_auto_translated_physmap)) {
- /* Make pagetable pieces RO */
- set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
- set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
- set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
- set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
- set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
- set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
- set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
- set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
-
- /* Pin down new L4 */
- pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
- PFN_DOWN(__pa_symbol(init_level4_pgt)));
-
- /* Unpin Xen-provided one */
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
- /*
- * At this stage there can be no user pgd, and no page
- * structure to attach it to, so make sure we just set kernel
- * pgd.
- */
- xen_mc_batch();
- __xen_write_cr3(true, __pa(init_level4_pgt));
- xen_mc_issue(PARAVIRT_LAZY_CPU);
- } else
- native_write_cr3(__pa(init_level4_pgt));
-
- /* We can't that easily rip out L3 and L2, as the Xen pagetables are
- * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
- * the initial domain. For guests using the toolstack, they are in:
- * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
- * rip out the [L4] (pgd), but for guests we shave off three pages.
- */
- for (i = 0; i < ARRAY_SIZE(addr); i++)
- check_pt_base(&pt_base, &pt_end, addr[i]);
-
- /* Our (by three pages) smaller Xen pagetable that we are using */
- xen_pt_base = PFN_PHYS(pt_base);
- xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
- memblock_reserve(xen_pt_base, xen_pt_size);
-
- /* Revector the xen_start_info */
- xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
-}
-
-/*
- * Read a value from a physical address.
- */
-static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
-{
- unsigned long *vaddr;
- unsigned long val;
+#include <linux/pfn.h>
+#include <asm/xen/page.h>
+#include <asm/xen/hypercall.h>
+#include <xen/interface/memory.h>

- vaddr = early_memremap_ro(addr, sizeof(val));
- val = *vaddr;
- early_memunmap(vaddr, sizeof(val));
- return val;
-}
+#include "multicalls.h"
+#include "mmu.h"

/*
- * Translate a virtual address to a physical one without relying on mapped
- * page tables.
+ * Protects atomic reservation decrease/increase against concurrent increases.
+ * Also protects non-atomic updates of current_pages and balloon lists.
*/
-static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
-{
- phys_addr_t pa;
- pgd_t pgd;
- pud_t pud;
- pmd_t pmd;
- pte_t pte;
-
- pa = read_cr3();
- pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
- sizeof(pgd)));
- if (!pgd_present(pgd))
- return 0;
-
- pa = pgd_val(pgd) & PTE_PFN_MASK;
- pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
- sizeof(pud)));
- if (!pud_present(pud))
- return 0;
- pa = pud_pfn(pud) << PAGE_SHIFT;
- if (pud_large(pud))
- return pa + (vaddr & ~PUD_MASK);
-
- pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
- sizeof(pmd)));
- if (!pmd_present(pmd))
- return 0;
- pa = pmd_pfn(pmd) << PAGE_SHIFT;
- if (pmd_large(pmd))
- return pa + (vaddr & ~PMD_MASK);
-
- pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
- sizeof(pte)));
- if (!pte_present(pte))
- return 0;
- pa = pte_pfn(pte) << PAGE_SHIFT;
-
- return pa | (vaddr & ~PAGE_MASK);
-}
+DEFINE_SPINLOCK(xen_reservation_lock);

-/*
- * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
- * this area.
- */
-void __init xen_relocate_p2m(void)
+unsigned long arbitrary_virt_to_mfn(void *vaddr)
{
- phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
- unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
- int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
- pte_t *pt;
- pmd_t *pmd;
- pud_t *pud;
- pgd_t *pgd;
- unsigned long *new_p2m;
-
- size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
- n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
- n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
- n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
- n_pud = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
- n_frames = n_pte + n_pt + n_pmd + n_pud;
-
- new_area = xen_find_free_area(PFN_PHYS(n_frames));
- if (!new_area) {
- xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
- BUG();
- }
-
- /*
- * Setup the page tables for addressing the new p2m list.
- * We have asked the hypervisor to map the p2m list at the user address
- * PUD_SIZE. It may have done so, or it may have used a kernel space
- * address depending on the Xen version.
- * To avoid any possible virtual address collision, just use
- * 2 * PUD_SIZE for the new area.
- */
- pud_phys = new_area;
- pmd_phys = pud_phys + PFN_PHYS(n_pud);
- pt_phys = pmd_phys + PFN_PHYS(n_pmd);
- p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
-
- pgd = __va(read_cr3());
- new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
- for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
- pud = early_memremap(pud_phys, PAGE_SIZE);
- clear_page(pud);
- for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
- idx_pmd++) {
- pmd = early_memremap(pmd_phys, PAGE_SIZE);
- clear_page(pmd);
- for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
- idx_pt++) {
- pt = early_memremap(pt_phys, PAGE_SIZE);
- clear_page(pt);
- for (idx_pte = 0;
- idx_pte < min(n_pte, PTRS_PER_PTE);
- idx_pte++) {
- set_pte(pt + idx_pte,
- pfn_pte(p2m_pfn, PAGE_KERNEL));
- p2m_pfn++;
- }
- n_pte -= PTRS_PER_PTE;
- early_memunmap(pt, PAGE_SIZE);
- make_lowmem_page_readonly(__va(pt_phys));
- pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
- PFN_DOWN(pt_phys));
- set_pmd(pmd + idx_pt,
- __pmd(_PAGE_TABLE | pt_phys));
- pt_phys += PAGE_SIZE;
- }
- n_pt -= PTRS_PER_PMD;
- early_memunmap(pmd, PAGE_SIZE);
- make_lowmem_page_readonly(__va(pmd_phys));
- pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
- PFN_DOWN(pmd_phys));
- set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
- pmd_phys += PAGE_SIZE;
- }
- n_pmd -= PTRS_PER_PUD;
- early_memunmap(pud, PAGE_SIZE);
- make_lowmem_page_readonly(__va(pud_phys));
- pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
- set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
- pud_phys += PAGE_SIZE;
- }
-
- /* Now copy the old p2m info to the new area. */
- memcpy(new_p2m, xen_p2m_addr, size);
- xen_p2m_addr = new_p2m;
-
- /* Release the old p2m list and set new list info. */
- p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
- BUG_ON(!p2m_pfn);
- p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
-
- if (xen_start_info->mfn_list < __START_KERNEL_map) {
- pfn = xen_start_info->first_p2m_pfn;
- pfn_end = xen_start_info->first_p2m_pfn +
- xen_start_info->nr_p2m_frames;
- set_pgd(pgd + 1, __pgd(0));
- } else {
- pfn = p2m_pfn;
- pfn_end = p2m_pfn_end;
- }
-
- memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
- while (pfn < pfn_end) {
- if (pfn == p2m_pfn) {
- pfn = p2m_pfn_end;
- continue;
- }
- make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
- pfn++;
- }
+ xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);

- xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
- xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
- xen_start_info->nr_p2m_frames = n_frames;
+ return PFN_DOWN(maddr.maddr);
}

-#else /* !CONFIG_X86_64 */
-static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
-static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
-
-static void __init xen_write_cr3_init(unsigned long cr3)
+xmaddr_t arbitrary_virt_to_machine(void *vaddr)
{
- unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
-
- BUG_ON(read_cr3() != __pa(initial_page_table));
- BUG_ON(cr3 != __pa(swapper_pg_dir));
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+ pte_t *pte;
+ unsigned offset;

/*
- * We are switching to swapper_pg_dir for the first time (from
- * initial_page_table) and therefore need to mark that page
- * read-only and then pin it.
- *
- * Xen disallows sharing of kernel PMDs for PAE
- * guests. Therefore we must copy the kernel PMD from
- * initial_page_table into a new kernel PMD to be used in
- * swapper_pg_dir.
+ * if the PFN is in the linear mapped vaddr range, we can just use
+ * the (quick) virt_to_machine() p2m lookup
*/
- swapper_kernel_pmd =
- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
- copy_page(swapper_kernel_pmd, initial_kernel_pmd);
- swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
- __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
- set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
-
- set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
- xen_write_cr3(cr3);
- pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
-
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
- PFN_DOWN(__pa(initial_page_table)));
- set_page_prot(initial_page_table, PAGE_KERNEL);
- set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
-
- pv_mmu_ops.write_cr3 = &xen_write_cr3;
-}
-
-/*
- * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
- * not the first page table in the page table pool.
- * Iterate through the initial page tables to find the real page table base.
- */
-static phys_addr_t xen_find_pt_base(pmd_t *pmd)
-{
- phys_addr_t pt_base, paddr;
- unsigned pmdidx;
-
- pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
-
- for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
- if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
- paddr = m2p(pmd[pmdidx].pmd);
- pt_base = min(pt_base, paddr);
- }
-
- return pt_base;
-}
-
-void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
-{
- pmd_t *kernel_pmd;
-
- kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
-
- xen_pt_base = xen_find_pt_base(kernel_pmd);
- xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
-
- initial_kernel_pmd =
- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
-
- max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
-
- copy_page(initial_kernel_pmd, kernel_pmd);
-
- xen_map_identity_early(initial_kernel_pmd, max_pfn);
-
- copy_page(initial_page_table, pgd);
- initial_page_table[KERNEL_PGD_BOUNDARY] =
- __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
-
- set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
- set_page_prot(initial_page_table, PAGE_KERNEL_RO);
- set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
-
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
- pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
- PFN_DOWN(__pa(initial_page_table)));
- xen_write_cr3(__pa(initial_page_table));
-
- memblock_reserve(xen_pt_base, xen_pt_size);
-}
-#endif /* CONFIG_X86_64 */
-
-void __init xen_reserve_special_pages(void)
-{
- phys_addr_t paddr;
-
- memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
- if (xen_start_info->store_mfn) {
- paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
- memblock_reserve(paddr, PAGE_SIZE);
- }
- if (!xen_initial_domain()) {
- paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
- memblock_reserve(paddr, PAGE_SIZE);
- }
-}
-
-void __init xen_pt_check_e820(void)
-{
- if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
- xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
- BUG();
- }
-}
-
-static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
-
-static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
-{
- pte_t pte;
-
- phys >>= PAGE_SHIFT;
-
- switch (idx) {
- case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
- case FIX_RO_IDT:
-#ifdef CONFIG_X86_32
- case FIX_WP_TEST:
-# ifdef CONFIG_HIGHMEM
- case FIX_KMAP_BEGIN ... FIX_KMAP_END:
-# endif
-#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
- case VSYSCALL_PAGE:
-#endif
- case FIX_TEXT_POKE0:
- case FIX_TEXT_POKE1:
- /* All local page mappings */
- pte = pfn_pte(phys, prot);
- break;
-
-#ifdef CONFIG_X86_LOCAL_APIC
- case FIX_APIC_BASE: /* maps dummy local APIC */
- pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
- break;
-#endif
-
-#ifdef CONFIG_X86_IO_APIC
- case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
- /*
- * We just don't map the IO APIC - all access is via
- * hypercalls. Keep the address in the pte for reference.
- */
- pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
- break;
-#endif
-
- case FIX_PARAVIRT_BOOTMAP:
- /* This is an MFN, but it isn't an IO mapping from the
- IO domain */
- pte = mfn_pte(phys, prot);
- break;
-
- default:
- /* By default, set_fixmap is used for hardware mappings */
- pte = mfn_pte(phys, prot);
- break;
- }
-
- __native_set_fixmap(idx, pte);
-
-#ifdef CONFIG_X86_VSYSCALL_EMULATION
- /* Replicate changes to map the vsyscall page into the user
- pagetable vsyscall mapping. */
- if (idx == VSYSCALL_PAGE) {
- unsigned long vaddr = __fix_to_virt(idx);
- set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
- }
-#endif
-}
-
-static void __init xen_post_allocator_init(void)
-{
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return;
-
- pv_mmu_ops.set_pte = xen_set_pte;
- pv_mmu_ops.set_pmd = xen_set_pmd;
- pv_mmu_ops.set_pud = xen_set_pud;
-#if CONFIG_PGTABLE_LEVELS == 4
- pv_mmu_ops.set_pgd = xen_set_pgd;
-#endif
-
- /* This will work as long as patching hasn't happened yet
- (which it hasn't) */
- pv_mmu_ops.alloc_pte = xen_alloc_pte;
- pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
- pv_mmu_ops.release_pte = xen_release_pte;
- pv_mmu_ops.release_pmd = xen_release_pmd;
-#if CONFIG_PGTABLE_LEVELS == 4
- pv_mmu_ops.alloc_pud = xen_alloc_pud;
- pv_mmu_ops.release_pud = xen_release_pud;
-#endif
- pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte);
-
-#ifdef CONFIG_X86_64
- pv_mmu_ops.write_cr3 = &xen_write_cr3;
- SetPagePinned(virt_to_page(level3_user_vsyscall));
-#endif
- xen_mark_init_mm_pinned();
-}
-
-static void xen_leave_lazy_mmu(void)
-{
- preempt_disable();
- xen_mc_flush();
- paravirt_leave_lazy_mmu();
- preempt_enable();
-}
-
-static const struct pv_mmu_ops xen_mmu_ops __initconst = {
- .read_cr2 = xen_read_cr2,
- .write_cr2 = xen_write_cr2,
-
- .read_cr3 = xen_read_cr3,
- .write_cr3 = xen_write_cr3_init,
-
- .flush_tlb_user = xen_flush_tlb,
- .flush_tlb_kernel = xen_flush_tlb,
- .flush_tlb_single = xen_flush_tlb_single,
- .flush_tlb_others = xen_flush_tlb_others,
-
- .pte_update = paravirt_nop,
-
- .pgd_alloc = xen_pgd_alloc,
- .pgd_free = xen_pgd_free,
-
- .alloc_pte = xen_alloc_pte_init,
- .release_pte = xen_release_pte_init,
- .alloc_pmd = xen_alloc_pmd_init,
- .release_pmd = xen_release_pmd_init,
-
- .set_pte = xen_set_pte_init,
- .set_pte_at = xen_set_pte_at,
- .set_pmd = xen_set_pmd_hyper,
-
- .ptep_modify_prot_start = __ptep_modify_prot_start,
- .ptep_modify_prot_commit = __ptep_modify_prot_commit,
-
- .pte_val = PV_CALLEE_SAVE(xen_pte_val),
- .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
-
- .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
- .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
-
-#ifdef CONFIG_X86_PAE
- .set_pte_atomic = xen_set_pte_atomic,
- .pte_clear = xen_pte_clear,
- .pmd_clear = xen_pmd_clear,
-#endif /* CONFIG_X86_PAE */
- .set_pud = xen_set_pud_hyper,
-
- .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
- .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
-
-#if CONFIG_PGTABLE_LEVELS == 4
- .pud_val = PV_CALLEE_SAVE(xen_pud_val),
- .make_pud = PV_CALLEE_SAVE(xen_make_pud),
- .set_pgd = xen_set_pgd_hyper,
-
- .alloc_pud = xen_alloc_pmd_init,
- .release_pud = xen_release_pmd_init,
-#endif /* CONFIG_PGTABLE_LEVELS == 4 */
-
- .activate_mm = xen_activate_mm,
- .dup_mmap = xen_dup_mmap,
- .exit_mmap = xen_exit_mmap,
-
- .lazy_mode = {
- .enter = paravirt_enter_lazy_mmu,
- .leave = xen_leave_lazy_mmu,
- .flush = paravirt_flush_lazy_mmu,
- },
-
- .set_fixmap = xen_set_fixmap,
-};
-
-void __init xen_init_mmu_ops(void)
-{
- x86_init.paging.pagetable_init = xen_pagetable_init;
-
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return;
+ if (virt_addr_valid(vaddr))
+ return virt_to_machine(vaddr);

- pv_mmu_ops = xen_mmu_ops;
+ /* otherwise we have to do a (slower) full page-table walk */

- memset(dummy_mapping, 0xff, PAGE_SIZE);
+ pte = lookup_address(address, &level);
+ BUG_ON(pte == NULL);
+ offset = address & ~PAGE_MASK;
+ return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
}
+EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);

-/* Protected by xen_reservation_lock. */
-#define MAX_CONTIG_ORDER 9 /* 2MB */
-static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
-
-#define VOID_PTE (mfn_pte(0, __pgprot(0)))
-static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
- unsigned long *in_frames,
- unsigned long *out_frames)
+void xen_flush_tlb_all(void)
{
- int i;
+ struct mmuext_op *op;
struct multicall_space mcs;

- xen_mc_batch();
- for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
- mcs = __xen_mc_entry(0);
-
- if (in_frames)
- in_frames[i] = virt_to_mfn(vaddr);
-
- MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
- __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
-
- if (out_frames)
- out_frames[i] = virt_to_pfn(vaddr);
- }
- xen_mc_issue(0);
-}
-
-/*
- * Update the pfn-to-mfn mappings for a virtual address range, either to
- * point to an array of mfns, or contiguously from a single starting
- * mfn.
- */
-static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
- unsigned long *mfns,
- unsigned long first_mfn)
-{
- unsigned i, limit;
- unsigned long mfn;
-
- xen_mc_batch();
-
- limit = 1u << order;
- for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
- struct multicall_space mcs;
- unsigned flags;
-
- mcs = __xen_mc_entry(0);
- if (mfns)
- mfn = mfns[i];
- else
- mfn = first_mfn + i;
-
- if (i < (limit - 1))
- flags = 0;
- else {
- if (order == 0)
- flags = UVMF_INVLPG | UVMF_ALL;
- else
- flags = UVMF_TLB_FLUSH | UVMF_ALL;
- }
-
- MULTI_update_va_mapping(mcs.mc, vaddr,
- mfn_pte(mfn, PAGE_KERNEL), flags);
-
- set_phys_to_machine(virt_to_pfn(vaddr), mfn);
- }
-
- xen_mc_issue(0);
-}
-
-/*
- * Perform the hypercall to exchange a region of our pfns to point to
- * memory with the required contiguous alignment. Takes the pfns as
- * input, and populates mfns as output.
- *
- * Returns a success code indicating whether the hypervisor was able to
- * satisfy the request or not.
- */
-static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
- unsigned long *pfns_in,
- unsigned long extents_out,
- unsigned int order_out,
- unsigned long *mfns_out,
- unsigned int address_bits)
-{
- long rc;
- int success;
-
- struct xen_memory_exchange exchange = {
- .in = {
- .nr_extents = extents_in,
- .extent_order = order_in,
- .extent_start = pfns_in,
- .domid = DOMID_SELF
- },
- .out = {
- .nr_extents = extents_out,
- .extent_order = order_out,
- .extent_start = mfns_out,
- .address_bits = address_bits,
- .domid = DOMID_SELF
- }
- };
-
- BUG_ON(extents_in << order_in != extents_out << order_out);
-
- rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
- success = (exchange.nr_exchanged == extents_in);
-
- BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
- BUG_ON(success && (rc != 0));
-
- return success;
-}
-
-int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
- unsigned int address_bits,
- dma_addr_t *dma_handle)
-{
- unsigned long *in_frames = discontig_frames, out_frame;
- unsigned long flags;
- int success;
- unsigned long vstart = (unsigned long)phys_to_virt(pstart);
-
- /*
- * Currently an auto-translated guest will not perform I/O, nor will
- * it require PAE page directories below 4GB. Therefore any calls to
- * this function are redundant and can be ignored.
- */
-
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return 0;
-
- if (unlikely(order > MAX_CONTIG_ORDER))
- return -ENOMEM;
-
- memset((void *) vstart, 0, PAGE_SIZE << order);
-
- spin_lock_irqsave(&xen_reservation_lock, flags);
-
- /* 1. Zap current PTEs, remembering MFNs. */
- xen_zap_pfn_range(vstart, order, in_frames, NULL);
-
- /* 2. Get a new contiguous memory extent. */
- out_frame = virt_to_pfn(vstart);
- success = xen_exchange_memory(1UL << order, 0, in_frames,
- 1, order, &out_frame,
- address_bits);
-
- /* 3. Map the new extent in place of old pages. */
- if (success)
- xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
- else
- xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
-
- spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
- *dma_handle = virt_to_machine(vstart).maddr;
- return success ? 0 : -ENOMEM;
-}
-EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
-
-void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
-{
- unsigned long *out_frames = discontig_frames, in_frame;
- unsigned long flags;
- int success;
- unsigned long vstart;
-
- if (xen_feature(XENFEAT_auto_translated_physmap))
- return;
-
- if (unlikely(order > MAX_CONTIG_ORDER))
- return;
-
- vstart = (unsigned long)phys_to_virt(pstart);
- memset((void *) vstart, 0, PAGE_SIZE << order);
-
- spin_lock_irqsave(&xen_reservation_lock, flags);
+ trace_xen_mmu_flush_tlb_all(0);

- /* 1. Find start MFN of contiguous extent. */
- in_frame = virt_to_mfn(vstart);
+ preempt_disable();

- /* 2. Zap current PTEs. */
- xen_zap_pfn_range(vstart, order, NULL, out_frames);
+ mcs = xen_mc_entry(sizeof(*op));

- /* 3. Do the exchange for non-contiguous MFNs. */
- success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
- 0, out_frames, 0);
+ op = mcs.args;
+ op->cmd = MMUEXT_TLB_FLUSH_ALL;
+ MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);

- /* 4. Map new pages in place of old pages. */
- if (success)
- xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
- else
- xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
+ xen_mc_issue(PARAVIRT_LAZY_MMU);

- spin_unlock_irqrestore(&xen_reservation_lock, flags);
+ preempt_enable();
}
-EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);

#define REMAP_BATCH_SIZE 16

@@ -2818,7 +191,6 @@ int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
}
EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);

-
/* Returns: 0 success */
int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
int numpgs, struct page **pages)
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
new file mode 100644
index 0000000..49137fd
--- /dev/null
+++ b/arch/x86/xen/mmu_pv.c
@@ -0,0 +1,2635 @@
+/*
+ * Xen mmu operations
+ *
+ * This file contains the various mmu fetch and update operations.
+ * The most important job they must perform is the mapping between the
+ * domain's pfn and the overall machine mfns.
+ *
+ * Xen allows guests to directly update the pagetable, in a controlled
+ * fashion. In other words, the guest modifies the same pagetable
+ * that the CPU actually uses, which eliminates the overhead of having
+ * a separate shadow pagetable.
+ *
+ * In order to allow this, it falls on the guest domain to map its
+ * notion of a "physical" pfn - which is just a domain-local linear
+ * address - into a real "machine address" which the CPU's MMU can
+ * use.
+ *
+ * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
+ * inserted directly into the pagetable. When creating a new
+ * pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
+ * when reading the content back with __(pgd|pmd|pte)_val, it converts
+ * the mfn back into a pfn.
+ *
+ * The other constraint is that all pages which make up a pagetable
+ * must be mapped read-only in the guest. This prevents uncontrolled
+ * guest updates to the pagetable. Xen strictly enforces this, and
+ * will disallow any pagetable update which will end up mapping a
+ * pagetable page RW, and will disallow using any writable page as a
+ * pagetable.
+ *
+ * Naively, when loading %cr3 with the base of a new pagetable, Xen
+ * would need to validate the whole pagetable before going on.
+ * Naturally, this is quite slow. The solution is to "pin" a
+ * pagetable, which enforces all the constraints on the pagetable even
+ * when it is not actively in use. This menas that Xen can be assured
+ * that it is still valid when you do load it into %cr3, and doesn't
+ * need to revalidate it.
+ *
+ * Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>, XenSource Inc, 2007
+ */
+#include <linux/sched.h>
+#include <linux/highmem.h>
+#include <linux/debugfs.h>
+#include <linux/bug.h>
+#include <linux/vmalloc.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+#include <linux/seq_file.h>
+#include <linux/crash_dump.h>
+
+#include <trace/events/xen.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
+#include <asm/mmu_context.h>
+#include <asm/setup.h>
+#include <asm/paravirt.h>
+#include <asm/e820.h>
+#include <asm/linkage.h>
+#include <asm/page.h>
+#include <asm/init.h>
+#include <asm/pat.h>
+#include <asm/smp.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/version.h>
+#include <xen/interface/memory.h>
+#include <xen/hvc-console.h>
+
+#include "multicalls.h"
+#include "mmu.h"
+#include "debugfs.h"
+
+#ifdef CONFIG_X86_32
+/*
+ * Identity map, in addition to plain kernel map. This needs to be
+ * large enough to allocate page table pages to allocate the rest.
+ * Each page can map 2MB.
+ */
+#define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
+static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
+#endif
+#ifdef CONFIG_X86_64
+/* l3 pud for userspace vsyscall mapping */
+static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
+#endif /* CONFIG_X86_64 */
+
+/*
+ * Note about cr3 (pagetable base) values:
+ *
+ * xen_cr3 contains the current logical cr3 value; it contains the
+ * last set cr3. This may not be the current effective cr3, because
+ * its update may be being lazily deferred. However, a vcpu looking
+ * at its own cr3 can use this value knowing that it everything will
+ * be self-consistent.
+ *
+ * xen_current_cr3 contains the actual vcpu cr3; it is set once the
+ * hypercall to set the vcpu cr3 is complete (so it may be a little
+ * out of date, but it will never be set early). If one vcpu is
+ * looking at another vcpu's cr3 value, it should use this variable.
+ */
+DEFINE_PER_CPU(unsigned long, xen_cr3); /* cr3 stored as physaddr */
+DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
+
+static phys_addr_t xen_pt_base, xen_pt_size __initdata;
+
+/*
+ * Just beyond the highest usermode address. STACK_TOP_MAX has a
+ * redzone above it, so round it up to a PGD boundary.
+ */
+#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
+
+void make_lowmem_page_readonly(void *vaddr)
+{
+ pte_t *pte, ptev;
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+
+ pte = lookup_address(address, &level);
+ if (pte == NULL)
+ return; /* vaddr missing */
+
+ ptev = pte_wrprotect(*pte);
+
+ if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+ BUG();
+}
+
+void make_lowmem_page_readwrite(void *vaddr)
+{
+ pte_t *pte, ptev;
+ unsigned long address = (unsigned long)vaddr;
+ unsigned int level;
+
+ pte = lookup_address(address, &level);
+ if (pte == NULL)
+ return; /* vaddr missing */
+
+ ptev = pte_mkwrite(*pte);
+
+ if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+ BUG();
+}
+
+
+static bool xen_page_pinned(void *ptr)
+{
+ struct page *page = virt_to_page(ptr);
+
+ return PagePinned(page);
+}
+
+void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
+{
+ struct multicall_space mcs;
+ struct mmu_update *u;
+
+ trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
+
+ mcs = xen_mc_entry(sizeof(*u));
+ u = mcs.args;
+
+ /* ptep might be kmapped when using 32-bit HIGHPTE */
+ u->ptr = virt_to_machine(ptep).maddr;
+ u->val = pte_val_ma(pteval);
+
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+EXPORT_SYMBOL_GPL(xen_set_domain_pte);
+
+static void xen_extend_mmu_update(const struct mmu_update *update)
+{
+ struct multicall_space mcs;
+ struct mmu_update *u;
+
+ mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+ if (mcs.mc != NULL) {
+ mcs.mc->args[1]++;
+ } else {
+ mcs = __xen_mc_entry(sizeof(*u));
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+ }
+
+ u = mcs.args;
+ *u = *update;
+}
+
+static void xen_extend_mmuext_op(const struct mmuext_op *op)
+{
+ struct multicall_space mcs;
+ struct mmuext_op *u;
+
+ mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
+
+ if (mcs.mc != NULL) {
+ mcs.mc->args[1]++;
+ } else {
+ mcs = __xen_mc_entry(sizeof(*u));
+ MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+ }
+
+ u = mcs.args;
+ *u = *op;
+}
+
+static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
+{
+ struct mmu_update u;
+
+ preempt_disable();
+
+ xen_mc_batch();
+
+ /* ptr may be ioremapped for 64-bit pagetable setup */
+ u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+ u.val = pmd_val_ma(val);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+ trace_xen_mmu_set_pmd(ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ xen_set_pmd_hyper(ptr, val);
+}
+
+/*
+ * Associate a virtual page frame with a given physical page frame
+ * and protection flags for that frame.
+ */
+void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
+{
+ set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
+}
+
+static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
+{
+ struct mmu_update u;
+
+ if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
+ return false;
+
+ xen_mc_batch();
+
+ u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
+ u.val = pte_val_ma(pteval);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ return true;
+}
+
+static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+ if (!xen_batched_set_pte(ptep, pteval)) {
+ /*
+ * Could call native_set_pte() here and trap and
+ * emulate the PTE write but with 32-bit guests this
+ * needs two traps (one for each of the two 32-bit
+ * words in the PTE) so do one hypercall directly
+ * instead.
+ */
+ struct mmu_update u;
+
+ u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
+ u.val = pte_val_ma(pteval);
+ HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF);
+ }
+}
+
+static void xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+ trace_xen_mmu_set_pte(ptep, pteval);
+ __xen_set_pte(ptep, pteval);
+}
+
+static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pteval)
+{
+ trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
+ __xen_set_pte(ptep, pteval);
+}
+
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ /* Just return the pte as-is. We preserve the bits on commit */
+ trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
+ return *ptep;
+}
+
+void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ struct mmu_update u;
+
+ trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
+ xen_mc_batch();
+
+ u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+ u.val = pte_val_ma(pte);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+/* Assume pteval_t is equivalent to all the other *val_t types. */
+static pteval_t pte_mfn_to_pfn(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ unsigned long pfn = mfn_to_pfn(mfn);
+
+ pteval_t flags = val & PTE_FLAGS_MASK;
+ if (unlikely(pfn == ~0))
+ val = flags & ~_PAGE_PRESENT;
+ else
+ val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
+static pteval_t pte_pfn_to_mfn(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+ unsigned long mfn;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ mfn = __pfn_to_mfn(pfn);
+ else
+ mfn = pfn;
+ /*
+ * If there's no mfn for the pfn, then just create an
+ * empty non-present pte. Unfortunately this loses
+ * information about the original pfn, so
+ * pte_mfn_to_pfn is asymmetric.
+ */
+ if (unlikely(mfn == INVALID_P2M_ENTRY)) {
+ mfn = 0;
+ flags = 0;
+ } else
+ mfn &= ~(FOREIGN_FRAME_BIT | IDENTITY_FRAME_BIT);
+ val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
+__visible pteval_t xen_pte_val(pte_t pte)
+{
+ pteval_t pteval = pte.pte;
+
+ return pte_mfn_to_pfn(pteval);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
+
+__visible pgdval_t xen_pgd_val(pgd_t pgd)
+{
+ return pte_mfn_to_pfn(pgd.pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
+
+__visible pte_t xen_make_pte(pteval_t pte)
+{
+ pte = pte_pfn_to_mfn(pte);
+
+ return native_make_pte(pte);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
+
+__visible pgd_t xen_make_pgd(pgdval_t pgd)
+{
+ pgd = pte_pfn_to_mfn(pgd);
+ return native_make_pgd(pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
+
+__visible pmdval_t xen_pmd_val(pmd_t pmd)
+{
+ return pte_mfn_to_pfn(pmd.pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
+
+static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
+{
+ struct mmu_update u;
+
+ preempt_disable();
+
+ xen_mc_batch();
+
+ /* ptr may be ioremapped for 64-bit pagetable setup */
+ u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+ u.val = pud_val_ma(val);
+ xen_extend_mmu_update(&u);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pud(pud_t *ptr, pud_t val)
+{
+ trace_xen_mmu_set_pud(ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ return;
+ }
+
+ xen_set_pud_hyper(ptr, val);
+}
+
+#ifdef CONFIG_X86_PAE
+static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+ trace_xen_mmu_set_pte_atomic(ptep, pte);
+ set_64bit((u64 *)ptep, native_pte_val(pte));
+}
+
+static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+ trace_xen_mmu_pte_clear(mm, addr, ptep);
+ if (!xen_batched_set_pte(ptep, native_make_pte(0)))
+ native_pte_clear(mm, addr, ptep);
+}
+
+static void xen_pmd_clear(pmd_t *pmdp)
+{
+ trace_xen_mmu_pmd_clear(pmdp);
+ set_pmd(pmdp, __pmd(0));
+}
+#endif /* CONFIG_X86_PAE */
+
+__visible pmd_t xen_make_pmd(pmdval_t pmd)
+{
+ pmd = pte_pfn_to_mfn(pmd);
+ return native_make_pmd(pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
+
+#if CONFIG_PGTABLE_LEVELS == 4
+__visible pudval_t xen_pud_val(pud_t pud)
+{
+ return pte_mfn_to_pfn(pud.pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
+
+__visible pud_t xen_make_pud(pudval_t pud)
+{
+ pud = pte_pfn_to_mfn(pud);
+
+ return native_make_pud(pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
+
+static pgd_t *xen_get_user_pgd(pgd_t *pgd)
+{
+ pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
+ unsigned offset = pgd - pgd_page;
+ pgd_t *user_ptr = NULL;
+
+ if (offset < pgd_index(USER_LIMIT)) {
+ struct page *page = virt_to_page(pgd_page);
+ user_ptr = (pgd_t *)page->private;
+ if (user_ptr)
+ user_ptr += offset;
+ }
+
+ return user_ptr;
+}
+
+static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+ struct mmu_update u;
+
+ u.ptr = virt_to_machine(ptr).maddr;
+ u.val = pgd_val_ma(val);
+ xen_extend_mmu_update(&u);
+}
+
+/*
+ * Raw hypercall-based set_pgd, intended for in early boot before
+ * there's a page structure. This implies:
+ * 1. The only existing pagetable is the kernel's
+ * 2. It is always pinned
+ * 3. It has no user pagetable attached to it
+ */
+static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+ preempt_disable();
+
+ xen_mc_batch();
+
+ __xen_set_pgd_hyper(ptr, val);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_set_pgd(pgd_t *ptr, pgd_t val)
+{
+ pgd_t *user_ptr = xen_get_user_pgd(ptr);
+
+ trace_xen_mmu_set_pgd(ptr, user_ptr, val);
+
+ /* If page is not pinned, we can just update the entry
+ directly */
+ if (!xen_page_pinned(ptr)) {
+ *ptr = val;
+ if (user_ptr) {
+ WARN_ON(xen_page_pinned(user_ptr));
+ *user_ptr = val;
+ }
+ return;
+ }
+
+ /* If it's pinned, then we can at least batch the kernel and
+ user updates together. */
+ xen_mc_batch();
+
+ __xen_set_pgd_hyper(ptr, val);
+ if (user_ptr)
+ __xen_set_pgd_hyper(user_ptr, val);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+#endif /* CONFIG_PGTABLE_LEVELS == 4 */
+
+/*
+ * (Yet another) pagetable walker. This one is intended for pinning a
+ * pagetable. This means that it walks a pagetable and calls the
+ * callback function on each page it finds making up the page table,
+ * at every level. It walks the entire pagetable, but it only bothers
+ * pinning pte pages which are below limit. In the normal case this
+ * will be STACK_TOP_MAX, but at boot we need to pin up to
+ * FIXADDR_TOP.
+ *
+ * For 32-bit the important bit is that we don't pin beyond there,
+ * because then we start getting into Xen's ptes.
+ *
+ * For 64-bit, we must skip the Xen hole in the middle of the address
+ * space, just after the big x86-64 virtual hole.
+ */
+static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
+ int (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
+{
+ int flush = 0;
+ unsigned hole_low, hole_high;
+ unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
+ unsigned pgdidx, pudidx, pmdidx;
+
+ /* The limit is the last byte to be touched */
+ limit--;
+ BUG_ON(limit >= FIXADDR_TOP);
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return 0;
+
+ /*
+ * 64-bit has a great big hole in the middle of the address
+ * space, which contains the Xen mappings. On 32-bit these
+ * will end up making a zero-sized hole and so is a no-op.
+ */
+ hole_low = pgd_index(USER_LIMIT);
+ hole_high = pgd_index(PAGE_OFFSET);
+
+ pgdidx_limit = pgd_index(limit);
+#if PTRS_PER_PUD > 1
+ pudidx_limit = pud_index(limit);
+#else
+ pudidx_limit = 0;
+#endif
+#if PTRS_PER_PMD > 1
+ pmdidx_limit = pmd_index(limit);
+#else
+ pmdidx_limit = 0;
+#endif
+
+ for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
+ pud_t *pud;
+
+ if (pgdidx >= hole_low && pgdidx < hole_high)
+ continue;
+
+ if (!pgd_val(pgd[pgdidx]))
+ continue;
+
+ pud = pud_offset(&pgd[pgdidx], 0);
+
+ if (PTRS_PER_PUD > 1) /* not folded */
+ flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
+
+ for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
+ pmd_t *pmd;
+
+ if (pgdidx == pgdidx_limit &&
+ pudidx > pudidx_limit)
+ goto out;
+
+ if (pud_none(pud[pudidx]))
+ continue;
+
+ pmd = pmd_offset(&pud[pudidx], 0);
+
+ if (PTRS_PER_PMD > 1) /* not folded */
+ flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
+
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
+ struct page *pte;
+
+ if (pgdidx == pgdidx_limit &&
+ pudidx == pudidx_limit &&
+ pmdidx > pmdidx_limit)
+ goto out;
+
+ if (pmd_none(pmd[pmdidx]))
+ continue;
+
+ pte = pmd_page(pmd[pmdidx]);
+ flush |= (*func)(mm, pte, PT_PTE);
+ }
+ }
+ }
+
+out:
+ /* Do the top level last, so that the callbacks can use it as
+ a cue to do final things like tlb flushes. */
+ flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
+
+ return flush;
+}
+
+static int xen_pgd_walk(struct mm_struct *mm,
+ int (*func)(struct mm_struct *mm, struct page *,
+ enum pt_level),
+ unsigned long limit)
+{
+ return __xen_pgd_walk(mm, mm->pgd, func, limit);
+}
+
+/* If we're using split pte locks, then take the page's lock and
+ return a pointer to it. Otherwise return NULL. */
+static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
+{
+ spinlock_t *ptl = NULL;
+
+#if USE_SPLIT_PTE_PTLOCKS
+ ptl = ptlock_ptr(page);
+ spin_lock_nest_lock(ptl, &mm->page_table_lock);
+#endif
+
+ return ptl;
+}
+
+static void xen_pte_unlock(void *v)
+{
+ spinlock_t *ptl = v;
+ spin_unlock(ptl);
+}
+
+static void xen_do_pin(unsigned level, unsigned long pfn)
+{
+ struct mmuext_op op;
+
+ op.cmd = level;
+ op.arg1.mfn = pfn_to_mfn(pfn);
+
+ xen_extend_mmuext_op(&op);
+}
+
+static int xen_pin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ unsigned pgfl = TestSetPagePinned(page);
+ int flush;
+
+ if (pgfl)
+ flush = 0; /* already pinned */
+ else if (PageHighMem(page))
+ /* kmaps need flushing if we found an unpinned
+ highpage */
+ flush = 1;
+ else {
+ void *pt = lowmem_page_address(page);
+ unsigned long pfn = page_to_pfn(page);
+ struct multicall_space mcs = __xen_mc_entry(0);
+ spinlock_t *ptl;
+
+ flush = 0;
+
+ /*
+ * We need to hold the pagetable lock between the time
+ * we make the pagetable RO and when we actually pin
+ * it. If we don't, then other users may come in and
+ * attempt to update the pagetable by writing it,
+ * which will fail because the memory is RO but not
+ * pinned, so Xen won't do the trap'n'emulate.
+ *
+ * If we're using split pte locks, we can't hold the
+ * entire pagetable's worth of locks during the
+ * traverse, because we may wrap the preempt count (8
+ * bits). The solution is to mark RO and pin each PTE
+ * page while holding the lock. This means the number
+ * of locks we end up holding is never more than a
+ * batch size (~32 entries, at present).
+ *
+ * If we're not using split pte locks, we needn't pin
+ * the PTE pages independently, because we're
+ * protected by the overall pagetable lock.
+ */
+ ptl = NULL;
+ if (level == PT_PTE)
+ ptl = xen_pte_lock(page, mm);
+
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+ pfn_pte(pfn, PAGE_KERNEL_RO),
+ level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+ if (ptl) {
+ xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
+
+ /* Queue a deferred unlock for when this batch
+ is completed. */
+ xen_mc_callback(xen_pte_unlock, ptl);
+ }
+ }
+
+ return flush;
+}
+
+/* This is called just after a mm has been created, but it has not
+ been used yet. We need to make sure that its pagetable is all
+ read-only, and can be pinned. */
+static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
+{
+ trace_xen_mmu_pgd_pin(mm, pgd);
+
+ xen_mc_batch();
+
+ if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
+ /* re-enable interrupts for flushing */
+ xen_mc_issue(0);
+
+ kmap_flush_unused();
+
+ xen_mc_batch();
+ }
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
+
+ if (user_pgd) {
+ xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
+ xen_do_pin(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
+ }
+ }
+#else /* CONFIG_X86_32 */
+#ifdef CONFIG_X86_PAE
+ /* Need to make sure unshared kernel PMD is pinnable */
+ xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+ PT_PMD);
+#endif
+ xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
+#endif /* CONFIG_X86_64 */
+ xen_mc_issue(0);
+}
+
+static void xen_pgd_pin(struct mm_struct *mm)
+{
+ __xen_pgd_pin(mm, mm->pgd);
+}
+
+/*
+ * On save, we need to pin all pagetables to make sure they get their
+ * mfns turned into pfns. Search the list for any unpinned pgds and pin
+ * them (unpinned pgds are not currently in use, probably because the
+ * process is under construction or destruction).
+ *
+ * Expected to be called in stop_machine() ("equivalent to taking
+ * every spinlock in the system"), so the locking doesn't really
+ * matter all that much.
+ */
+void xen_mm_pin_all(void)
+{
+ struct page *page;
+
+ spin_lock(&pgd_lock);
+
+ list_for_each_entry(page, &pgd_list, lru) {
+ if (!PagePinned(page)) {
+ __xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
+ SetPageSavePinned(page);
+ }
+ }
+
+ spin_unlock(&pgd_lock);
+}
+
+/*
+ * The init_mm pagetable is really pinned as soon as its created, but
+ * that's before we have page structures to store the bits. So do all
+ * the book-keeping now.
+ */
+static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ SetPagePinned(page);
+ return 0;
+}
+
+static void __init xen_mark_init_mm_pinned(void)
+{
+ xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
+}
+
+static int xen_unpin_page(struct mm_struct *mm, struct page *page,
+ enum pt_level level)
+{
+ unsigned pgfl = TestClearPagePinned(page);
+
+ if (pgfl && !PageHighMem(page)) {
+ void *pt = lowmem_page_address(page);
+ unsigned long pfn = page_to_pfn(page);
+ spinlock_t *ptl = NULL;
+ struct multicall_space mcs;
+
+ /*
+ * Do the converse to pin_page. If we're using split
+ * pte locks, we must be holding the lock for while
+ * the pte page is unpinned but still RO to prevent
+ * concurrent updates from seeing it in this
+ * partially-pinned state.
+ */
+ if (level == PT_PTE) {
+ ptl = xen_pte_lock(page, mm);
+
+ if (ptl)
+ xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+ }
+
+ mcs = __xen_mc_entry(0);
+
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+ pfn_pte(pfn, PAGE_KERNEL),
+ level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+ if (ptl) {
+ /* unlock when batch completed */
+ xen_mc_callback(xen_pte_unlock, ptl);
+ }
+ }
+
+ return 0; /* never need to flush on unpin */
+}
+
+/* Release a pagetables pages back as normal RW */
+static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
+{
+ trace_xen_mmu_pgd_unpin(mm, pgd);
+
+ xen_mc_batch();
+
+ xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ if (user_pgd) {
+ xen_do_pin(MMUEXT_UNPIN_TABLE,
+ PFN_DOWN(__pa(user_pgd)));
+ xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
+ }
+ }
+#endif
+
+#ifdef CONFIG_X86_PAE
+ /* Need to make sure unshared kernel PMD is unpinned */
+ xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+ PT_PMD);
+#endif
+
+ __xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
+
+ xen_mc_issue(0);
+}
+
+static void xen_pgd_unpin(struct mm_struct *mm)
+{
+ __xen_pgd_unpin(mm, mm->pgd);
+}
+
+/*
+ * On resume, undo any pinning done at save, so that the rest of the
+ * kernel doesn't see any unexpected pinned pagetables.
+ */
+void xen_mm_unpin_all(void)
+{
+ struct page *page;
+
+ spin_lock(&pgd_lock);
+
+ list_for_each_entry(page, &pgd_list, lru) {
+ if (PageSavePinned(page)) {
+ BUG_ON(!PagePinned(page));
+ __xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
+ ClearPageSavePinned(page);
+ }
+ }
+
+ spin_unlock(&pgd_lock);
+}
+
+static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+ spin_lock(&next->page_table_lock);
+ xen_pgd_pin(next);
+ spin_unlock(&next->page_table_lock);
+}
+
+static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+ spin_lock(&mm->page_table_lock);
+ xen_pgd_pin(mm);
+ spin_unlock(&mm->page_table_lock);
+}
+
+
+#ifdef CONFIG_SMP
+/* Another cpu may still have their %cr3 pointing at the pagetable, so
+ we need to repoint it somewhere else before we can unpin it. */
+static void drop_other_mm_ref(void *info)
+{
+ struct mm_struct *mm = info;
+ struct mm_struct *active_mm;
+
+ active_mm = this_cpu_read(cpu_tlbstate.active_mm);
+
+ if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
+ leave_mm(smp_processor_id());
+
+ /* If this cpu still has a stale cr3 reference, then make sure
+ it has been flushed. */
+ if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
+ load_cr3(swapper_pg_dir);
+}
+
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+ cpumask_var_t mask;
+ unsigned cpu;
+
+ if (current->active_mm == mm) {
+ if (current->mm == mm)
+ load_cr3(swapper_pg_dir);
+ else
+ leave_mm(smp_processor_id());
+ }
+
+ /* Get the "official" set of cpus referring to our pagetable. */
+ if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
+ for_each_online_cpu(cpu) {
+ if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
+ && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
+ continue;
+ smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
+ }
+ return;
+ }
+ cpumask_copy(mask, mm_cpumask(mm));
+
+ /* It's possible that a vcpu may have a stale reference to our
+ cr3, because its in lazy mode, and it hasn't yet flushed
+ its set of pending hypercalls yet. In this case, we can
+ look at its actual current cr3 value, and force it to flush
+ if needed. */
+ for_each_online_cpu(cpu) {
+ if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
+ cpumask_set_cpu(cpu, mask);
+ }
+
+ if (!cpumask_empty(mask))
+ smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
+ free_cpumask_var(mask);
+}
+#else
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+ if (current->active_mm == mm)
+ load_cr3(swapper_pg_dir);
+}
+#endif
+
+/*
+ * While a process runs, Xen pins its pagetables, which means that the
+ * hypervisor forces it to be read-only, and it controls all updates
+ * to it. This means that all pagetable updates have to go via the
+ * hypervisor, which is moderately expensive.
+ *
+ * Since we're pulling the pagetable down, we switch to use init_mm,
+ * unpin old process pagetable and mark it all read-write, which
+ * allows further operations on it to be simple memory accesses.
+ *
+ * The only subtle point is that another CPU may be still using the
+ * pagetable because of lazy tlb flushing. This means we need need to
+ * switch all CPUs off this pagetable before we can unpin it.
+ */
+static void xen_exit_mmap(struct mm_struct *mm)
+{
+ get_cpu(); /* make sure we don't move around */
+ xen_drop_mm_ref(mm);
+ put_cpu();
+
+ spin_lock(&mm->page_table_lock);
+
+ /* pgd may not be pinned in the error exit path of execve */
+ if (xen_page_pinned(mm->pgd))
+ xen_pgd_unpin(mm);
+
+ spin_unlock(&mm->page_table_lock);
+}
+
+static void xen_post_allocator_init(void);
+
+static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+ struct mmuext_op op;
+
+ op.cmd = cmd;
+ op.arg1.mfn = pfn_to_mfn(pfn);
+ if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+ BUG();
+}
+
+#ifdef CONFIG_X86_64
+static void __init xen_cleanhighmap(unsigned long vaddr,
+ unsigned long vaddr_end)
+{
+ unsigned long kernel_end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1;
+ pmd_t *pmd = level2_kernel_pgt + pmd_index(vaddr);
+
+ /* NOTE: The loop is more greedy than the cleanup_highmap variant.
+ * We include the PMD passed in on _both_ boundaries. */
+ for (; vaddr <= vaddr_end && (pmd < (level2_kernel_pgt + PTRS_PER_PMD));
+ pmd++, vaddr += PMD_SIZE) {
+ if (pmd_none(*pmd))
+ continue;
+ if (vaddr < (unsigned long) _text || vaddr > kernel_end)
+ set_pmd(pmd, __pmd(0));
+ }
+ /* In case we did something silly, we should crash in this function
+ * instead of somewhere later and be confusing. */
+ xen_mc_flush();
+}
+
+/*
+ * Make a page range writeable and free it.
+ */
+static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
+{
+ void *vaddr = __va(paddr);
+ void *vaddr_end = vaddr + size;
+
+ for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
+ make_lowmem_page_readwrite(vaddr);
+
+ memblock_free(paddr, size);
+}
+
+static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
+{
+ unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
+
+ if (unpin)
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
+ ClearPagePinned(virt_to_page(__va(pa)));
+ xen_free_ro_pages(pa, PAGE_SIZE);
+}
+
+/*
+ * Since it is well isolated we can (and since it is perhaps large we should)
+ * also free the page tables mapping the initial P->M table.
+ */
+static void __init xen_cleanmfnmap(unsigned long vaddr)
+{
+ unsigned long va = vaddr & PMD_MASK;
+ unsigned long pa;
+ pgd_t *pgd = pgd_offset_k(va);
+ pud_t *pud_page = pud_offset(pgd, 0);
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+ unsigned int i;
+ bool unpin;
+
+ unpin = (vaddr == 2 * PGDIR_SIZE);
+ set_pgd(pgd, __pgd(0));
+ do {
+ pud = pud_page + pud_index(va);
+ if (pud_none(*pud)) {
+ va += PUD_SIZE;
+ } else if (pud_large(*pud)) {
+ pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
+ xen_free_ro_pages(pa, PUD_SIZE);
+ va += PUD_SIZE;
+ } else {
+ pmd = pmd_offset(pud, va);
+ if (pmd_large(*pmd)) {
+ pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
+ xen_free_ro_pages(pa, PMD_SIZE);
+ } else if (!pmd_none(*pmd)) {
+ pte = pte_offset_kernel(pmd, va);
+ set_pmd(pmd, __pmd(0));
+ for (i = 0; i < PTRS_PER_PTE; ++i) {
+ if (pte_none(pte[i]))
+ break;
+ pa = pte_pfn(pte[i]) << PAGE_SHIFT;
+ xen_free_ro_pages(pa, PAGE_SIZE);
+ }
+ xen_cleanmfnmap_free_pgtbl(pte, unpin);
+ }
+ va += PMD_SIZE;
+ if (pmd_index(va))
+ continue;
+ set_pud(pud, __pud(0));
+ xen_cleanmfnmap_free_pgtbl(pmd, unpin);
+ }
+
+ } while (pud_index(va) || pmd_index(va));
+ xen_cleanmfnmap_free_pgtbl(pud_page, unpin);
+}
+
+static void __init xen_pagetable_p2m_free(void)
+{
+ unsigned long size;
+ unsigned long addr;
+
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+
+ /* No memory or already called. */
+ if ((unsigned long)xen_p2m_addr == xen_start_info->mfn_list)
+ return;
+
+ /* using __ka address and sticking INVALID_P2M_ENTRY! */
+ memset((void *)xen_start_info->mfn_list, 0xff, size);
+
+ addr = xen_start_info->mfn_list;
+ /*
+ * We could be in __ka space.
+ * We roundup to the PMD, which means that if anybody at this stage is
+ * using the __ka address of xen_start_info or
+ * xen_start_info->shared_info they are in going to crash. Fortunatly
+ * we have already revectored in xen_setup_kernel_pagetable and in
+ * xen_setup_shared_info.
+ */
+ size = roundup(size, PMD_SIZE);
+
+ if (addr >= __START_KERNEL_map) {
+ xen_cleanhighmap(addr, addr + size);
+ size = PAGE_ALIGN(xen_start_info->nr_pages *
+ sizeof(unsigned long));
+ memblock_free(__pa(addr), size);
+ } else {
+ xen_cleanmfnmap(addr);
+ }
+}
+
+static void __init xen_pagetable_cleanhighmap(void)
+{
+ unsigned long size;
+ unsigned long addr;
+
+ /* At this stage, cleanup_highmap has already cleaned __ka space
+ * from _brk_limit way up to the max_pfn_mapped (which is the end of
+ * the ramdisk). We continue on, erasing PMD entries that point to page
+ * tables - do note that they are accessible at this stage via __va.
+ * For good measure we also round up to the PMD - which means that if
+ * anybody is using __ka address to the initial boot-stack - and try
+ * to use it - they are going to crash. The xen_start_info has been
+ * taken care of already in xen_setup_kernel_pagetable. */
+ addr = xen_start_info->pt_base;
+ size = roundup(xen_start_info->nr_pt_frames * PAGE_SIZE, PMD_SIZE);
+
+ xen_cleanhighmap(addr, addr + size);
+ xen_start_info->pt_base = (unsigned long)__va(__pa(xen_start_info->pt_base));
+#ifdef DEBUG
+ /* This is superfluous and is not necessary, but you know what
+ * lets do it. The MODULES_VADDR -> MODULES_END should be clear of
+ * anything at this stage. */
+ xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
+#endif
+}
+#endif
+
+static void __init xen_pagetable_p2m_setup(void)
+{
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ xen_vmalloc_p2m_tree();
+
+#ifdef CONFIG_X86_64
+ xen_pagetable_p2m_free();
+
+ xen_pagetable_cleanhighmap();
+#endif
+ /* And revector! Bye bye old array */
+ xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
+}
+
+static void __init xen_pagetable_init(void)
+{
+ paging_init();
+ xen_post_allocator_init();
+
+ xen_pagetable_p2m_setup();
+
+ /* Allocate and initialize top and mid mfn levels for p2m structure */
+ xen_build_mfn_list_list();
+
+ /* Remap memory freed due to conflicts with E820 map */
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ xen_remap_memory();
+
+ xen_setup_shared_info();
+}
+static void xen_write_cr2(unsigned long cr2)
+{
+ this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
+}
+
+static unsigned long xen_read_cr2(void)
+{
+ return this_cpu_read(xen_vcpu)->arch.cr2;
+}
+
+unsigned long xen_read_cr2_direct(void)
+{
+ return this_cpu_read(xen_vcpu_info.arch.cr2);
+}
+
+static void xen_flush_tlb(void)
+{
+ struct mmuext_op *op;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb(0);
+
+ preempt_disable();
+
+ mcs = xen_mc_entry(sizeof(*op));
+
+ op = mcs.args;
+ op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
+ MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_flush_tlb_single(unsigned long addr)
+{
+ struct mmuext_op *op;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb_single(addr);
+
+ preempt_disable();
+
+ mcs = xen_mc_entry(sizeof(*op));
+ op = mcs.args;
+ op->cmd = MMUEXT_INVLPG_LOCAL;
+ op->arg1.linear_addr = addr & PAGE_MASK;
+ MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+ preempt_enable();
+}
+
+static void xen_flush_tlb_others(const struct cpumask *cpus,
+ struct mm_struct *mm, unsigned long start,
+ unsigned long end)
+{
+ struct {
+ struct mmuext_op op;
+#ifdef CONFIG_SMP
+ DECLARE_BITMAP(mask, num_processors);
+#else
+ DECLARE_BITMAP(mask, NR_CPUS);
+#endif
+ } *args;
+ struct multicall_space mcs;
+
+ trace_xen_mmu_flush_tlb_others(cpus, mm, start, end);
+
+ if (cpumask_empty(cpus))
+ return; /* nothing to do */
+
+ mcs = xen_mc_entry(sizeof(*args));
+ args = mcs.args;
+ args->op.arg2.vcpumask = to_cpumask(args->mask);
+
+ /* Remove us, and any offline CPUS. */
+ cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
+ cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
+
+ args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
+ if (end != TLB_FLUSH_ALL && (end - start) <= PAGE_SIZE) {
+ args->op.cmd = MMUEXT_INVLPG_MULTI;
+ args->op.arg1.linear_addr = start;
+ }
+
+ MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static unsigned long xen_read_cr3(void)
+{
+ return this_cpu_read(xen_cr3);
+}
+
+static void set_current_cr3(void *v)
+{
+ this_cpu_write(xen_current_cr3, (unsigned long)v);
+}
+
+static void __xen_write_cr3(bool kernel, unsigned long cr3)
+{
+ struct mmuext_op op;
+ unsigned long mfn;
+
+ trace_xen_mmu_write_cr3(kernel, cr3);
+
+ if (cr3)
+ mfn = pfn_to_mfn(PFN_DOWN(cr3));
+ else
+ mfn = 0;
+
+ WARN_ON(mfn == 0 && kernel);
+
+ op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
+ op.arg1.mfn = mfn;
+
+ xen_extend_mmuext_op(&op);
+
+ if (kernel) {
+ this_cpu_write(xen_cr3, cr3);
+
+ /* Update xen_current_cr3 once the batch has actually
+ been submitted. */
+ xen_mc_callback(set_current_cr3, (void *)cr3);
+ }
+}
+static void xen_write_cr3(unsigned long cr3)
+{
+ BUG_ON(preemptible());
+
+ xen_mc_batch(); /* disables interrupts */
+
+ /* Update while interrupts are disabled, so its atomic with
+ respect to ipis */
+ this_cpu_write(xen_cr3, cr3);
+
+ __xen_write_cr3(true, cr3);
+
+#ifdef CONFIG_X86_64
+ {
+ pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
+ if (user_pgd)
+ __xen_write_cr3(false, __pa(user_pgd));
+ else
+ __xen_write_cr3(false, 0);
+ }
+#endif
+
+ xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
+}
+
+#ifdef CONFIG_X86_64
+/*
+ * At the start of the day - when Xen launches a guest, it has already
+ * built pagetables for the guest. We diligently look over them
+ * in xen_setup_kernel_pagetable and graft as appropriate them in the
+ * init_level4_pgt and its friends. Then when we are happy we load
+ * the new init_level4_pgt - and continue on.
+ *
+ * The generic code starts (start_kernel) and 'init_mem_mapping' sets
+ * up the rest of the pagetables. When it has completed it loads the cr3.
+ * N.B. that baremetal would start at 'start_kernel' (and the early
+ * #PF handler would create bootstrap pagetables) - so we are running
+ * with the same assumptions as what to do when write_cr3 is executed
+ * at this point.
+ *
+ * Since there are no user-page tables at all, we have two variants
+ * of xen_write_cr3 - the early bootup (this one), and the late one
+ * (xen_write_cr3). The reason we have to do that is that in 64-bit
+ * the Linux kernel and user-space are both in ring 3 while the
+ * hypervisor is in ring 0.
+ */
+static void __init xen_write_cr3_init(unsigned long cr3)
+{
+ BUG_ON(preemptible());
+
+ xen_mc_batch(); /* disables interrupts */
+
+ /* Update while interrupts are disabled, so its atomic with
+ respect to ipis */
+ this_cpu_write(xen_cr3, cr3);
+
+ __xen_write_cr3(true, cr3);
+
+ xen_mc_issue(PARAVIRT_LAZY_CPU); /* interrupts restored */
+}
+#endif
+
+static int xen_pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = mm->pgd;
+ int ret = 0;
+
+ BUG_ON(PagePinned(virt_to_page(pgd)));
+
+#ifdef CONFIG_X86_64
+ {
+ struct page *page = virt_to_page(pgd);
+ pgd_t *user_pgd;
+
+ BUG_ON(page->private != 0);
+
+ ret = -ENOMEM;
+
+ user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+ page->private = (unsigned long)user_pgd;
+
+ if (user_pgd != NULL) {
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
+ user_pgd[pgd_index(VSYSCALL_ADDR)] =
+ __pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
+#endif
+ ret = 0;
+ }
+
+ BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
+ }
+#endif
+
+ return ret;
+}
+
+static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+#ifdef CONFIG_X86_64
+ pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+ if (user_pgd)
+ free_page((unsigned long)user_pgd);
+#endif
+}
+
+/*
+ * Init-time set_pte while constructing initial pagetables, which
+ * doesn't allow RO page table pages to be remapped RW.
+ *
+ * If there is no MFN for this PFN then this page is initially
+ * ballooned out so clear the PTE (as in decrease_reservation() in
+ * drivers/xen/balloon.c).
+ *
+ * Many of these PTE updates are done on unpinned and writable pages
+ * and doing a hypercall for these is unnecessary and expensive. At
+ * this point it is not possible to tell if a page is pinned or not,
+ * so always write the PTE directly and rely on Xen trapping and
+ * emulating any updates as necessary.
+ */
+__visible pte_t xen_make_pte_init(pteval_t pte)
+{
+#ifdef CONFIG_X86_64
+ unsigned long pfn;
+
+ /*
+ * Pages belonging to the initial p2m list mapped outside the default
+ * address range must be mapped read-only. This region contains the
+ * page tables for mapping the p2m list, too, and page tables MUST be
+ * mapped read-only.
+ */
+ pfn = (pte & PTE_PFN_MASK) >> PAGE_SHIFT;
+ if (xen_start_info->mfn_list < __START_KERNEL_map &&
+ pfn >= xen_start_info->first_p2m_pfn &&
+ pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
+ pte &= ~_PAGE_RW;
+#endif
+ pte = pte_pfn_to_mfn(pte);
+ return native_make_pte(pte);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte_init);
+
+static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
+{
+#ifdef CONFIG_X86_32
+ /* If there's an existing pte, then don't allow _PAGE_RW to be set */
+ if (pte_mfn(pte) != INVALID_P2M_ENTRY
+ && pte_val_ma(*ptep) & _PAGE_PRESENT)
+ pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
+ pte_val_ma(pte));
+#endif
+ native_set_pte(ptep, pte);
+}
+
+/* Early in boot, while setting up the initial pagetable, assume
+ everything is pinned. */
+static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+ BUG_ON(mem_map); /* should only be used early */
+#endif
+ make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+ pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+}
+
+/* Used for pmd and pud */
+static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+ BUG_ON(mem_map); /* should only be used early */
+#endif
+ make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+/* Early release_pte assumes that all pts are pinned, since there's
+ only init_mm and anything attached to that is pinned. */
+static void __init xen_release_pte_init(unsigned long pfn)
+{
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+ make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static void __init xen_release_pmd_init(unsigned long pfn)
+{
+ make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+ struct multicall_space mcs;
+ struct mmuext_op *op;
+
+ mcs = __xen_mc_entry(sizeof(*op));
+ op = mcs.args;
+ op->cmd = cmd;
+ op->arg1.mfn = pfn_to_mfn(pfn);
+
+ MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+}
+
+static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
+{
+ struct multicall_space mcs;
+ unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
+
+ mcs = __xen_mc_entry(0);
+ MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
+ pfn_pte(pfn, prot), 0);
+}
+
+/* This needs to make sure the new pte page is pinned iff its being
+ attached to a pinned pagetable. */
+static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
+ unsigned level)
+{
+ bool pinned = PagePinned(virt_to_page(mm->pgd));
+
+ trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
+
+ if (pinned) {
+ struct page *page = pfn_to_page(pfn);
+
+ SetPagePinned(page);
+
+ if (!PageHighMem(page)) {
+ xen_mc_batch();
+
+ __set_pfn_prot(pfn, PAGE_KERNEL_RO);
+
+ if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+ } else {
+ /* make sure there are no stray mappings of
+ this page */
+ kmap_flush_unused();
+ }
+ }
+}
+
+static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PTE);
+}
+
+static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PMD);
+}
+
+/* This should never happen until we're OK to use struct page */
+static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
+{
+ struct page *page = pfn_to_page(pfn);
+ bool pinned = PagePinned(page);
+
+ trace_xen_mmu_release_ptpage(pfn, level, pinned);
+
+ if (pinned) {
+ if (!PageHighMem(page)) {
+ xen_mc_batch();
+
+ if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+
+ __set_pfn_prot(pfn, PAGE_KERNEL);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+ }
+ ClearPagePinned(page);
+ }
+}
+
+static void xen_release_pte(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PTE);
+}
+
+static void xen_release_pmd(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PMD);
+}
+
+#if CONFIG_PGTABLE_LEVELS == 4
+static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
+{
+ xen_alloc_ptpage(mm, pfn, PT_PUD);
+}
+
+static void xen_release_pud(unsigned long pfn)
+{
+ xen_release_ptpage(pfn, PT_PUD);
+}
+#endif
+
+void __init xen_reserve_top(void)
+{
+#ifdef CONFIG_X86_32
+ unsigned long top = HYPERVISOR_VIRT_START;
+ struct xen_platform_parameters pp;
+
+ if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
+ top = pp.virt_start;
+
+ reserve_top_address(-top);
+#endif /* CONFIG_X86_32 */
+}
+
+/*
+ * Like __va(), but returns address in the kernel mapping (which is
+ * all we have until the physical memory mapping has been set up.
+ */
+static void * __init __ka(phys_addr_t paddr)
+{
+#ifdef CONFIG_X86_64
+ return (void *)(paddr + __START_KERNEL_map);
+#else
+ return __va(paddr);
+#endif
+}
+
+/* Convert a machine address to physical address */
+static unsigned long __init m2p(phys_addr_t maddr)
+{
+ phys_addr_t paddr;
+
+ maddr &= PTE_PFN_MASK;
+ paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
+
+ return paddr;
+}
+
+/* Convert a machine address to kernel virtual */
+static void * __init m2v(phys_addr_t maddr)
+{
+ return __ka(m2p(maddr));
+}
+
+/* Set the page permissions on an identity-mapped pages */
+static void __init set_page_prot_flags(void *addr, pgprot_t prot,
+ unsigned long flags)
+{
+ unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
+ pte_t pte = pfn_pte(pfn, prot);
+
+ if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
+ BUG();
+}
+static void __init set_page_prot(void *addr, pgprot_t prot)
+{
+ return set_page_prot_flags(addr, prot, UVMF_NONE);
+}
+#ifdef CONFIG_X86_32
+static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
+{
+ unsigned pmdidx, pteidx;
+ unsigned ident_pte;
+ unsigned long pfn;
+
+ level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
+ PAGE_SIZE);
+
+ ident_pte = 0;
+ pfn = 0;
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
+ pte_t *pte_page;
+
+ /* Reuse or allocate a page of ptes */
+ if (pmd_present(pmd[pmdidx]))
+ pte_page = m2v(pmd[pmdidx].pmd);
+ else {
+ /* Check for free pte pages */
+ if (ident_pte == LEVEL1_IDENT_ENTRIES)
+ break;
+
+ pte_page = &level1_ident_pgt[ident_pte];
+ ident_pte += PTRS_PER_PTE;
+
+ pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
+ }
+
+ /* Install mappings */
+ for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
+ pte_t pte;
+
+ if (pfn > max_pfn_mapped)
+ max_pfn_mapped = pfn;
+
+ if (!pte_none(pte_page[pteidx]))
+ continue;
+
+ pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
+ pte_page[pteidx] = pte;
+ }
+ }
+
+ for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
+ set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
+
+ set_page_prot(pmd, PAGE_KERNEL_RO);
+}
+#endif
+void __init xen_setup_machphys_mapping(void)
+{
+ struct xen_machphys_mapping mapping;
+
+ if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
+ machine_to_phys_mapping = (unsigned long *)mapping.v_start;
+ machine_to_phys_nr = mapping.max_mfn + 1;
+ } else {
+ machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
+ }
+#ifdef CONFIG_X86_32
+ WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
+ < machine_to_phys_mapping);
+#endif
+}
+
+#ifdef CONFIG_X86_64
+static void __init convert_pfn_mfn(void *v)
+{
+ pte_t *pte = v;
+ int i;
+
+ /* All levels are converted the same way, so just treat them
+ as ptes. */
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ pte[i] = xen_make_pte(pte[i].pte);
+}
+static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
+ unsigned long addr)
+{
+ if (*pt_base == PFN_DOWN(__pa(addr))) {
+ set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
+ clear_page((void *)addr);
+ (*pt_base)++;
+ }
+ if (*pt_end == PFN_DOWN(__pa(addr))) {
+ set_page_prot_flags((void *)addr, PAGE_KERNEL, UVMF_INVLPG);
+ clear_page((void *)addr);
+ (*pt_end)--;
+ }
+}
+/*
+ * Set up the initial kernel pagetable.
+ *
+ * We can construct this by grafting the Xen provided pagetable into
+ * head_64.S's preconstructed pagetables. We copy the Xen L2's into
+ * level2_ident_pgt, and level2_kernel_pgt. This means that only the
+ * kernel has a physical mapping to start with - but that's enough to
+ * get __va working. We need to fill in the rest of the physical
+ * mapping once some sort of allocator has been set up.
+ */
+void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
+{
+ pud_t *l3;
+ pmd_t *l2;
+ unsigned long addr[3];
+ unsigned long pt_base, pt_end;
+ unsigned i;
+
+ /* max_pfn_mapped is the last pfn mapped in the initial memory
+ * mappings. Considering that on Xen after the kernel mappings we
+ * have the mappings of some pages that don't exist in pfn space, we
+ * set max_pfn_mapped to the last real pfn mapped. */
+ if (xen_start_info->mfn_list < __START_KERNEL_map)
+ max_pfn_mapped = xen_start_info->first_p2m_pfn;
+ else
+ max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+
+ pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
+ pt_end = pt_base + xen_start_info->nr_pt_frames;
+
+ /* Zap identity mapping */
+ init_level4_pgt[0] = __pgd(0);
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Pre-constructed entries are in pfn, so convert to mfn */
+ /* L4[272] -> level3_ident_pgt
+ * L4[511] -> level3_kernel_pgt */
+ convert_pfn_mfn(init_level4_pgt);
+
+ /* L3_i[0] -> level2_ident_pgt */
+ convert_pfn_mfn(level3_ident_pgt);
+ /* L3_k[510] -> level2_kernel_pgt
+ * L3_k[511] -> level2_fixmap_pgt */
+ convert_pfn_mfn(level3_kernel_pgt);
+
+ /* L3_k[511][506] -> level1_fixmap_pgt */
+ convert_pfn_mfn(level2_fixmap_pgt);
+ }
+ /* We get [511][511] and have Xen's version of level2_kernel_pgt */
+ l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
+ l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
+
+ addr[0] = (unsigned long)pgd;
+ addr[1] = (unsigned long)l3;
+ addr[2] = (unsigned long)l2;
+ /* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
+ * Both L4[272][0] and L4[511][510] have entries that point to the same
+ * L2 (PMD) tables. Meaning that if you modify it in __va space
+ * it will be also modified in the __ka space! (But if you just
+ * modify the PMD table to point to other PTE's or none, then you
+ * are OK - which is what cleanup_highmap does) */
+ copy_page(level2_ident_pgt, l2);
+ /* Graft it onto L4[511][510] */
+ copy_page(level2_kernel_pgt, l2);
+
+ /* Copy the initial P->M table mappings if necessary. */
+ i = pgd_index(xen_start_info->mfn_list);
+ if (i && i < pgd_index(__START_KERNEL_map))
+ init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Make pagetable pieces RO */
+ set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
+ set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
+ set_page_prot(level1_fixmap_pgt, PAGE_KERNEL_RO);
+
+ /* Pin down new L4 */
+ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa_symbol(init_level4_pgt)));
+
+ /* Unpin Xen-provided one */
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+ /*
+ * At this stage there can be no user pgd, and no page
+ * structure to attach it to, so make sure we just set kernel
+ * pgd.
+ */
+ xen_mc_batch();
+ __xen_write_cr3(true, __pa(init_level4_pgt));
+ xen_mc_issue(PARAVIRT_LAZY_CPU);
+ } else
+ native_write_cr3(__pa(init_level4_pgt));
+
+ /* We can't that easily rip out L3 and L2, as the Xen pagetables are
+ * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
+ * the initial domain. For guests using the toolstack, they are in:
+ * [L4], [L3], [L2], [L1], [L1], order .. So for dom0 we can only
+ * rip out the [L4] (pgd), but for guests we shave off three pages.
+ */
+ for (i = 0; i < ARRAY_SIZE(addr); i++)
+ check_pt_base(&pt_base, &pt_end, addr[i]);
+
+ /* Our (by three pages) smaller Xen pagetable that we are using */
+ xen_pt_base = PFN_PHYS(pt_base);
+ xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
+ memblock_reserve(xen_pt_base, xen_pt_size);
+
+ /* Revector the xen_start_info */
+ xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
+}
+
+/*
+ * Read a value from a physical address.
+ */
+static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
+{
+ unsigned long *vaddr;
+ unsigned long val;
+
+ vaddr = early_memremap_ro(addr, sizeof(val));
+ val = *vaddr;
+ early_memunmap(vaddr, sizeof(val));
+ return val;
+}
+
+/*
+ * Translate a virtual address to a physical one without relying on mapped
+ * page tables.
+ */
+static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
+{
+ phys_addr_t pa;
+ pgd_t pgd;
+ pud_t pud;
+ pmd_t pmd;
+ pte_t pte;
+
+ pa = read_cr3();
+ pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
+ sizeof(pgd)));
+ if (!pgd_present(pgd))
+ return 0;
+
+ pa = pgd_val(pgd) & PTE_PFN_MASK;
+ pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
+ sizeof(pud)));
+ if (!pud_present(pud))
+ return 0;
+ pa = pud_pfn(pud) << PAGE_SHIFT;
+ if (pud_large(pud))
+ return pa + (vaddr & ~PUD_MASK);
+
+ pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
+ sizeof(pmd)));
+ if (!pmd_present(pmd))
+ return 0;
+ pa = pmd_pfn(pmd) << PAGE_SHIFT;
+ if (pmd_large(pmd))
+ return pa + (vaddr & ~PMD_MASK);
+
+ pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
+ sizeof(pte)));
+ if (!pte_present(pte))
+ return 0;
+ pa = pte_pfn(pte) << PAGE_SHIFT;
+
+ return pa | (vaddr & ~PAGE_MASK);
+}
+
+/*
+ * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
+ * this area.
+ */
+void __init xen_relocate_p2m(void)
+{
+ phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
+ unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
+ int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
+ pte_t *pt;
+ pmd_t *pmd;
+ pud_t *pud;
+ pgd_t *pgd;
+ unsigned long *new_p2m;
+
+ size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+ n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
+ n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
+ n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
+ n_pud = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
+ n_frames = n_pte + n_pt + n_pmd + n_pud;
+
+ new_area = xen_find_free_area(PFN_PHYS(n_frames));
+ if (!new_area) {
+ xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
+ BUG();
+ }
+
+ /*
+ * Setup the page tables for addressing the new p2m list.
+ * We have asked the hypervisor to map the p2m list at the user address
+ * PUD_SIZE. It may have done so, or it may have used a kernel space
+ * address depending on the Xen version.
+ * To avoid any possible virtual address collision, just use
+ * 2 * PUD_SIZE for the new area.
+ */
+ pud_phys = new_area;
+ pmd_phys = pud_phys + PFN_PHYS(n_pud);
+ pt_phys = pmd_phys + PFN_PHYS(n_pmd);
+ p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
+
+ pgd = __va(read_cr3());
+ new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
+ for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
+ pud = early_memremap(pud_phys, PAGE_SIZE);
+ clear_page(pud);
+ for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
+ idx_pmd++) {
+ pmd = early_memremap(pmd_phys, PAGE_SIZE);
+ clear_page(pmd);
+ for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
+ idx_pt++) {
+ pt = early_memremap(pt_phys, PAGE_SIZE);
+ clear_page(pt);
+ for (idx_pte = 0;
+ idx_pte < min(n_pte, PTRS_PER_PTE);
+ idx_pte++) {
+ set_pte(pt + idx_pte,
+ pfn_pte(p2m_pfn, PAGE_KERNEL));
+ p2m_pfn++;
+ }
+ n_pte -= PTRS_PER_PTE;
+ early_memunmap(pt, PAGE_SIZE);
+ make_lowmem_page_readonly(__va(pt_phys));
+ pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
+ PFN_DOWN(pt_phys));
+ set_pmd(pmd + idx_pt,
+ __pmd(_PAGE_TABLE | pt_phys));
+ pt_phys += PAGE_SIZE;
+ }
+ n_pt -= PTRS_PER_PMD;
+ early_memunmap(pmd, PAGE_SIZE);
+ make_lowmem_page_readonly(__va(pmd_phys));
+ pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
+ PFN_DOWN(pmd_phys));
+ set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
+ pmd_phys += PAGE_SIZE;
+ }
+ n_pmd -= PTRS_PER_PUD;
+ early_memunmap(pud, PAGE_SIZE);
+ make_lowmem_page_readonly(__va(pud_phys));
+ pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
+ set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
+ pud_phys += PAGE_SIZE;
+ }
+
+ /* Now copy the old p2m info to the new area. */
+ memcpy(new_p2m, xen_p2m_addr, size);
+ xen_p2m_addr = new_p2m;
+
+ /* Release the old p2m list and set new list info. */
+ p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
+ BUG_ON(!p2m_pfn);
+ p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
+
+ if (xen_start_info->mfn_list < __START_KERNEL_map) {
+ pfn = xen_start_info->first_p2m_pfn;
+ pfn_end = xen_start_info->first_p2m_pfn +
+ xen_start_info->nr_p2m_frames;
+ set_pgd(pgd + 1, __pgd(0));
+ } else {
+ pfn = p2m_pfn;
+ pfn_end = p2m_pfn_end;
+ }
+
+ memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
+ while (pfn < pfn_end) {
+ if (pfn == p2m_pfn) {
+ pfn = p2m_pfn_end;
+ continue;
+ }
+ make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+ pfn++;
+ }
+
+ xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
+ xen_start_info->first_p2m_pfn = PFN_DOWN(new_area);
+ xen_start_info->nr_p2m_frames = n_frames;
+}
+
+#else /* !CONFIG_X86_64 */
+static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
+static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
+
+static void __init xen_write_cr3_init(unsigned long cr3)
+{
+ unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
+
+ BUG_ON(read_cr3() != __pa(initial_page_table));
+ BUG_ON(cr3 != __pa(swapper_pg_dir));
+
+ /*
+ * We are switching to swapper_pg_dir for the first time (from
+ * initial_page_table) and therefore need to mark that page
+ * read-only and then pin it.
+ *
+ * Xen disallows sharing of kernel PMDs for PAE
+ * guests. Therefore we must copy the kernel PMD from
+ * initial_page_table into a new kernel PMD to be used in
+ * swapper_pg_dir.
+ */
+ swapper_kernel_pmd =
+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+ copy_page(swapper_kernel_pmd, initial_kernel_pmd);
+ swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
+ __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
+ set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
+
+ set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
+ xen_write_cr3(cr3);
+ pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
+
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
+ PFN_DOWN(__pa(initial_page_table)));
+ set_page_prot(initial_page_table, PAGE_KERNEL);
+ set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
+
+ pv_mmu_ops.write_cr3 = &xen_write_cr3;
+}
+
+/*
+ * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
+ * not the first page table in the page table pool.
+ * Iterate through the initial page tables to find the real page table base.
+ */
+static phys_addr_t xen_find_pt_base(pmd_t *pmd)
+{
+ phys_addr_t pt_base, paddr;
+ unsigned pmdidx;
+
+ pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
+
+ for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
+ if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
+ paddr = m2p(pmd[pmdidx].pmd);
+ pt_base = min(pt_base, paddr);
+ }
+
+ return pt_base;
+}
+
+void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
+{
+ pmd_t *kernel_pmd;
+
+ kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
+
+ xen_pt_base = xen_find_pt_base(kernel_pmd);
+ xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
+
+ initial_kernel_pmd =
+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+
+ max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
+
+ copy_page(initial_kernel_pmd, kernel_pmd);
+
+ xen_map_identity_early(initial_kernel_pmd, max_pfn);
+
+ copy_page(initial_page_table, pgd);
+ initial_page_table[KERNEL_PGD_BOUNDARY] =
+ __pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
+
+ set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
+ set_page_prot(initial_page_table, PAGE_KERNEL_RO);
+ set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
+
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+ pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
+ PFN_DOWN(__pa(initial_page_table)));
+ xen_write_cr3(__pa(initial_page_table));
+
+ memblock_reserve(xen_pt_base, xen_pt_size);
+}
+#endif /* CONFIG_X86_64 */
+
+void __init xen_reserve_special_pages(void)
+{
+ phys_addr_t paddr;
+
+ memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
+ if (xen_start_info->store_mfn) {
+ paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
+ memblock_reserve(paddr, PAGE_SIZE);
+ }
+ if (!xen_initial_domain()) {
+ paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
+ memblock_reserve(paddr, PAGE_SIZE);
+ }
+}
+
+void __init xen_pt_check_e820(void)
+{
+ if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
+ xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
+ BUG();
+ }
+}
+
+static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
+
+static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
+{
+ pte_t pte;
+
+ phys >>= PAGE_SHIFT;
+
+ switch (idx) {
+ case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
+ case FIX_RO_IDT:
+#ifdef CONFIG_X86_32
+ case FIX_WP_TEST:
+# ifdef CONFIG_HIGHMEM
+ case FIX_KMAP_BEGIN ... FIX_KMAP_END:
+# endif
+#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
+ case VSYSCALL_PAGE:
+#endif
+ case FIX_TEXT_POKE0:
+ case FIX_TEXT_POKE1:
+ /* All local page mappings */
+ pte = pfn_pte(phys, prot);
+ break;
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ case FIX_APIC_BASE: /* maps dummy local APIC */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
+#ifdef CONFIG_X86_IO_APIC
+ case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
+ /*
+ * We just don't map the IO APIC - all access is via
+ * hypercalls. Keep the address in the pte for reference.
+ */
+ pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+ break;
+#endif
+
+ case FIX_PARAVIRT_BOOTMAP:
+ /* This is an MFN, but it isn't an IO mapping from the
+ IO domain */
+ pte = mfn_pte(phys, prot);
+ break;
+
+ default:
+ /* By default, set_fixmap is used for hardware mappings */
+ pte = mfn_pte(phys, prot);
+ break;
+ }
+
+ __native_set_fixmap(idx, pte);
+
+#ifdef CONFIG_X86_VSYSCALL_EMULATION
+ /* Replicate changes to map the vsyscall page into the user
+ pagetable vsyscall mapping. */
+ if (idx == VSYSCALL_PAGE) {
+ unsigned long vaddr = __fix_to_virt(idx);
+ set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
+ }
+#endif
+}
+
+static void __init xen_post_allocator_init(void)
+{
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ pv_mmu_ops.set_pte = xen_set_pte;
+ pv_mmu_ops.set_pmd = xen_set_pmd;
+ pv_mmu_ops.set_pud = xen_set_pud;
+#if CONFIG_PGTABLE_LEVELS == 4
+ pv_mmu_ops.set_pgd = xen_set_pgd;
+#endif
+
+ /* This will work as long as patching hasn't happened yet
+ (which it hasn't) */
+ pv_mmu_ops.alloc_pte = xen_alloc_pte;
+ pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
+ pv_mmu_ops.release_pte = xen_release_pte;
+ pv_mmu_ops.release_pmd = xen_release_pmd;
+#if CONFIG_PGTABLE_LEVELS == 4
+ pv_mmu_ops.alloc_pud = xen_alloc_pud;
+ pv_mmu_ops.release_pud = xen_release_pud;
+#endif
+ pv_mmu_ops.make_pte = PV_CALLEE_SAVE(xen_make_pte);
+
+#ifdef CONFIG_X86_64
+ pv_mmu_ops.write_cr3 = &xen_write_cr3;
+ SetPagePinned(virt_to_page(level3_user_vsyscall));
+#endif
+ xen_mark_init_mm_pinned();
+}
+
+static void xen_leave_lazy_mmu(void)
+{
+ preempt_disable();
+ xen_mc_flush();
+ paravirt_leave_lazy_mmu();
+ preempt_enable();
+}
+
+static const struct pv_mmu_ops xen_mmu_ops __initconst = {
+ .read_cr2 = xen_read_cr2,
+ .write_cr2 = xen_write_cr2,
+
+ .read_cr3 = xen_read_cr3,
+ .write_cr3 = xen_write_cr3_init,
+
+ .flush_tlb_user = xen_flush_tlb,
+ .flush_tlb_kernel = xen_flush_tlb,
+ .flush_tlb_single = xen_flush_tlb_single,
+ .flush_tlb_others = xen_flush_tlb_others,
+
+ .pte_update = paravirt_nop,
+
+ .pgd_alloc = xen_pgd_alloc,
+ .pgd_free = xen_pgd_free,
+
+ .alloc_pte = xen_alloc_pte_init,
+ .release_pte = xen_release_pte_init,
+ .alloc_pmd = xen_alloc_pmd_init,
+ .release_pmd = xen_release_pmd_init,
+
+ .set_pte = xen_set_pte_init,
+ .set_pte_at = xen_set_pte_at,
+ .set_pmd = xen_set_pmd_hyper,
+
+ .ptep_modify_prot_start = __ptep_modify_prot_start,
+ .ptep_modify_prot_commit = __ptep_modify_prot_commit,
+
+ .pte_val = PV_CALLEE_SAVE(xen_pte_val),
+ .pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
+
+ .make_pte = PV_CALLEE_SAVE(xen_make_pte_init),
+ .make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
+
+#ifdef CONFIG_X86_PAE
+ .set_pte_atomic = xen_set_pte_atomic,
+ .pte_clear = xen_pte_clear,
+ .pmd_clear = xen_pmd_clear,
+#endif /* CONFIG_X86_PAE */
+ .set_pud = xen_set_pud_hyper,
+
+ .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
+ .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
+
+#if CONFIG_PGTABLE_LEVELS == 4
+ .pud_val = PV_CALLEE_SAVE(xen_pud_val),
+ .make_pud = PV_CALLEE_SAVE(xen_make_pud),
+ .set_pgd = xen_set_pgd_hyper,
+
+ .alloc_pud = xen_alloc_pmd_init,
+ .release_pud = xen_release_pmd_init,
+#endif /* CONFIG_PGTABLE_LEVELS == 4 */
+
+ .activate_mm = xen_activate_mm,
+ .dup_mmap = xen_dup_mmap,
+ .exit_mmap = xen_exit_mmap,
+
+ .lazy_mode = {
+ .enter = paravirt_enter_lazy_mmu,
+ .leave = xen_leave_lazy_mmu,
+ .flush = paravirt_flush_lazy_mmu,
+ },
+
+ .set_fixmap = xen_set_fixmap,
+};
+
+void __init xen_init_mmu_ops(void)
+{
+ x86_init.paging.pagetable_init = xen_pagetable_init;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ pv_mmu_ops = xen_mmu_ops;
+
+ memset(dummy_mapping, 0xff, PAGE_SIZE);
+}
+
+/* Protected by xen_reservation_lock. */
+#define MAX_CONTIG_ORDER 9 /* 2MB */
+static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
+
+#define VOID_PTE (mfn_pte(0, __pgprot(0)))
+static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
+ unsigned long *in_frames,
+ unsigned long *out_frames)
+{
+ int i;
+ struct multicall_space mcs;
+
+ xen_mc_batch();
+ for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
+ mcs = __xen_mc_entry(0);
+
+ if (in_frames)
+ in_frames[i] = virt_to_mfn(vaddr);
+
+ MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
+ __set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
+
+ if (out_frames)
+ out_frames[i] = virt_to_pfn(vaddr);
+ }
+ xen_mc_issue(0);
+}
+
+/*
+ * Update the pfn-to-mfn mappings for a virtual address range, either to
+ * point to an array of mfns, or contiguously from a single starting
+ * mfn.
+ */
+static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
+ unsigned long *mfns,
+ unsigned long first_mfn)
+{
+ unsigned i, limit;
+ unsigned long mfn;
+
+ xen_mc_batch();
+
+ limit = 1u << order;
+ for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
+ struct multicall_space mcs;
+ unsigned flags;
+
+ mcs = __xen_mc_entry(0);
+ if (mfns)
+ mfn = mfns[i];
+ else
+ mfn = first_mfn + i;
+
+ if (i < (limit - 1))
+ flags = 0;
+ else {
+ if (order == 0)
+ flags = UVMF_INVLPG | UVMF_ALL;
+ else
+ flags = UVMF_TLB_FLUSH | UVMF_ALL;
+ }
+
+ MULTI_update_va_mapping(mcs.mc, vaddr,
+ mfn_pte(mfn, PAGE_KERNEL), flags);
+
+ set_phys_to_machine(virt_to_pfn(vaddr), mfn);
+ }
+
+ xen_mc_issue(0);
+}
+
+/*
+ * Perform the hypercall to exchange a region of our pfns to point to
+ * memory with the required contiguous alignment. Takes the pfns as
+ * input, and populates mfns as output.
+ *
+ * Returns a success code indicating whether the hypervisor was able to
+ * satisfy the request or not.
+ */
+static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
+ unsigned long *pfns_in,
+ unsigned long extents_out,
+ unsigned int order_out,
+ unsigned long *mfns_out,
+ unsigned int address_bits)
+{
+ long rc;
+ int success;
+
+ struct xen_memory_exchange exchange = {
+ .in = {
+ .nr_extents = extents_in,
+ .extent_order = order_in,
+ .extent_start = pfns_in,
+ .domid = DOMID_SELF
+ },
+ .out = {
+ .nr_extents = extents_out,
+ .extent_order = order_out,
+ .extent_start = mfns_out,
+ .address_bits = address_bits,
+ .domid = DOMID_SELF
+ }
+ };
+
+ BUG_ON(extents_in << order_in != extents_out << order_out);
+
+ rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
+ success = (exchange.nr_exchanged == extents_in);
+
+ BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
+ BUG_ON(success && (rc != 0));
+
+ return success;
+}
+
+int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
+ unsigned int address_bits,
+ dma_addr_t *dma_handle)
+{
+ unsigned long *in_frames = discontig_frames, out_frame;
+ unsigned long flags;
+ int success;
+ unsigned long vstart = (unsigned long)phys_to_virt(pstart);
+
+ /*
+ * Currently an auto-translated guest will not perform I/O, nor will
+ * it require PAE page directories below 4GB. Therefore any calls to
+ * this function are redundant and can be ignored.
+ */
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return 0;
+
+ if (unlikely(order > MAX_CONTIG_ORDER))
+ return -ENOMEM;
+
+ memset((void *) vstart, 0, PAGE_SIZE << order);
+
+ spin_lock_irqsave(&xen_reservation_lock, flags);
+
+ /* 1. Zap current PTEs, remembering MFNs. */
+ xen_zap_pfn_range(vstart, order, in_frames, NULL);
+
+ /* 2. Get a new contiguous memory extent. */
+ out_frame = virt_to_pfn(vstart);
+ success = xen_exchange_memory(1UL << order, 0, in_frames,
+ 1, order, &out_frame,
+ address_bits);
+
+ /* 3. Map the new extent in place of old pages. */
+ if (success)
+ xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
+ else
+ xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
+
+ spin_unlock_irqrestore(&xen_reservation_lock, flags);
+
+ *dma_handle = virt_to_machine(vstart).maddr;
+ return success ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+
+void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
+{
+ unsigned long *out_frames = discontig_frames, in_frame;
+ unsigned long flags;
+ int success;
+ unsigned long vstart;
+
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
+ if (unlikely(order > MAX_CONTIG_ORDER))
+ return;
+
+ vstart = (unsigned long)phys_to_virt(pstart);
+ memset((void *) vstart, 0, PAGE_SIZE << order);
+
+ spin_lock_irqsave(&xen_reservation_lock, flags);
+
+ /* 1. Find start MFN of contiguous extent. */
+ in_frame = virt_to_mfn(vstart);
+
+ /* 2. Zap current PTEs. */
+ xen_zap_pfn_range(vstart, order, NULL, out_frames);
+
+ /* 3. Do the exchange for non-contiguous MFNs. */
+ success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
+ 0, out_frames, 0);
+
+ /* 4. Map new pages in place of old pages. */
+ if (success)
+ xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
+ else
+ xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
+
+ spin_unlock_irqrestore(&xen_reservation_lock, flags);
+}
+EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
--
2.9.3

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