Re: [PATCH V10 04/14] xen/pvh: bootup and setup (E820) related changes.

From: Boris Ostrovsky
Date: Fri Dec 13 2013 - 12:56:48 EST

On 12/12/2013 09:10 PM, Konrad Rzeszutek Wilk wrote:
From: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>

In the bootup code for PVH we can trap cpuid via vmexit, so don't
need to use emulated prefix call. We also check for vector callback
early on, as it is a required feature. PVH also runs at default kernel
IOPL.

In setup.c which deals with E820, in xen_add_extra_mem() we can skip
updating P2M as it's managed by Xen. PVH maps the entire IO space,
but only RAM pages need to be repopulated.

Finally, pure PV settings are moved to a separate function that are
only called for pure PV, ie, pv with pvmmu.

Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
[ ijc -- rebase onto xen PVonHVM: use E820_Reserved area for
shared_info ]
[v2: Rebase on v3.9-rc1 with MMIO/Kexec reverted]

Conflicts:
arch/x86/xen/setup.c
[due to "xen: Support 64-bit PV guest receiving NMIs"]
---
arch/x86/xen/enlighten.c | 77 ++++++++++++++++++++++++++++++++++-----------
arch/x86/xen/setup.c | 63 ++++++++++++++++++++++++++++++-------
2 files changed, 109 insertions(+), 31 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index fa6ade7..500508d 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -46,6 +46,7 @@
#include <xen/hvm.h>
#include <xen/hvc-console.h>
#include <xen/acpi.h>
+#include <xen/features.h>
#include <asm/paravirt.h>
#include <asm/apic.h>
@@ -129,6 +130,9 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
__read_mostly int xen_have_vector_callback;
EXPORT_SYMBOL_GPL(xen_have_vector_callback);
+#define xen_pvh_domain() (xen_pv_domain() && \
+ xen_feature(XENFEAT_auto_translated_physmap) && \
+ xen_have_vector_callback)

Can this be used in earlier patches instead of checking for XENFEAT_auto_translated_physmap, when it's clear that we actually mean PVH?

/*
* Point at some empty memory to start with. We map the real shared_info
* page as soon as fixmap is up and running.
@@ -262,8 +266,9 @@ static void __init xen_banner(void)
struct xen_extraversion extra;
HYPERVISOR_xen_version(XENVER_extraversion, &extra);
- printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
- pv_info.name);
+ pr_info("Booting paravirtualized kernel %son %s\n",
+ xen_feature(XENFEAT_auto_translated_physmap) ?

... and here as well (and possibly elsewhere).

+ "with PVH extensions " : "", pv_info.name);
printk(KERN_INFO "Xen version: %d.%d%s%s\n",
version >> 16, version & 0xffff, extra.extraversion,
xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
@@ -331,12 +336,15 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
break;
}
- asm(XEN_EMULATE_PREFIX "cpuid"
- : "=a" (*ax),
- "=b" (*bx),
- "=c" (*cx),
- "=d" (*dx)
- : "0" (*ax), "2" (*cx));
+ if (xen_pvh_domain())
+ native_cpuid(ax, bx, cx, dx);
+ else
+ asm(XEN_EMULATE_PREFIX "cpuid"
+ : "=a" (*ax),
+ "=b" (*bx),
+ "=c" (*cx),
+ "=d" (*dx)
+ : "0" (*ax), "2" (*cx));
*bx &= maskebx;
*cx &= maskecx;
@@ -1125,6 +1133,10 @@ void xen_setup_shared_info(void)
HYPERVISOR_shared_info =
(struct shared_info *)__va(xen_start_info->shared_info);
+ /* PVH TBD/FIXME: vcpu info placement in phase 2 */
+ if (xen_pvh_domain())
+ return;
+
#ifndef CONFIG_SMP
/* In UP this is as good a place as any to set up shared info */
xen_setup_vcpu_info_placement();
@@ -1410,6 +1422,11 @@ static void __init xen_boot_params_init_edd(void)
*/
static void __init xen_setup_stackprotector(void)
{
+ /* PVH TBD/FIXME: investigate setup_stack_canary_segment */

setup_stack_canary_segment() is for 32-bit only and since PVH (which I assume is what this 'if' is about) is a 64-bit only binary this call is a nop.

+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ switch_to_new_gdt(0);
+ return;
+ }
pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
pv_cpu_ops.load_gdt = xen_load_gdt_boot;
@@ -1420,6 +1437,19 @@ static void __init xen_setup_stackprotector(void)
pv_cpu_ops.load_gdt = xen_load_gdt;
}
+static void __init xen_pvh_early_guest_init(void)
+{
+ if (xen_feature(XENFEAT_hvm_callback_vector))
+ xen_have_vector_callback = 1;
+
+#ifdef CONFIG_X86_32
+ if (xen_feature(XENFEAT_auto_translated_physmap)) {
+ xen_raw_printk("ERROR: 32bit PVH guests are not supported\n");
+ BUG();
+ }
+#endif
+}
+
/* First C function to be called on Xen boot */
asmlinkage void __init xen_start_kernel(void)
{
@@ -1431,13 +1461,18 @@ asmlinkage void __init xen_start_kernel(void)
xen_domain_type = XEN_PV_DOMAIN;
+ xen_setup_features();
+ xen_pvh_early_guest_init();
xen_setup_machphys_mapping();
/* Install Xen paravirt ops */
pv_info = xen_info;
pv_init_ops = xen_init_ops;
- pv_cpu_ops = xen_cpu_ops;
pv_apic_ops = xen_apic_ops;
+ if (xen_pvh_domain())
+ pv_cpu_ops.cpuid = xen_cpuid;
+ else
+ pv_cpu_ops = xen_cpu_ops;
x86_init.resources.memory_setup = xen_memory_setup;
x86_init.oem.arch_setup = xen_arch_setup;
@@ -1469,8 +1504,6 @@ asmlinkage void __init xen_start_kernel(void)
/* Work out if we support NX */
x86_configure_nx();
- xen_setup_features();
-
/* Get mfn list */
if (!xen_feature(XENFEAT_auto_translated_physmap))
xen_build_dynamic_phys_to_machine();
@@ -1548,14 +1581,18 @@ asmlinkage void __init xen_start_kernel(void)
/* set the limit of our address space */
xen_reserve_top();
- /* We used to do this in xen_arch_setup, but that is too late on AMD
- * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
- * which pokes 0xcf8 port.
- */
- set_iopl.iopl = 1;
- rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
- if (rc != 0)
- xen_raw_printk("physdev_op failed %d\n", rc);
+ /* PVH: runs at default kernel iopl of 0 */
+ if (!xen_pvh_domain()) {
+ /*
+ * We used to do this in xen_arch_setup, but that is too late
+ * on AMD were early_cpu_init (run before ->arch_setup()) calls
+ * early_amd_init which pokes 0xcf8 port.
+ */
+ set_iopl.iopl = 1;
+ rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+ if (rc != 0)
+ xen_raw_printk("physdev_op failed %d\n", rc);
+ }
#ifdef CONFIG_X86_32
/* set up basic CPUID stuff */
@@ -1625,6 +1662,8 @@ asmlinkage void __init xen_start_kernel(void)
}
void __ref xen_hvm_init_shared_info(void)
+/* Use a pfn in RAM, may move to MMIO before kexec.
+ * This function also called for PVH dom0 */
{
int cpu;
struct xen_add_to_physmap xatp;
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 68c054f..e3dcd8c 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -27,6 +27,7 @@
#include <xen/interface/memory.h>
#include <xen/interface/physdev.h>
#include <xen/features.h>
+#include "mmu.h"
#include "xen-ops.h"
#include "vdso.h"
@@ -81,6 +82,9 @@ static void __init xen_add_extra_mem(u64 start, u64 size)
memblock_reserve(start, size);
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
xen_max_p2m_pfn = PFN_DOWN(start + size);
for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
unsigned long mfn = pfn_to_mfn(pfn);
@@ -103,6 +107,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
.domid = DOMID_SELF
};
unsigned long len = 0;
+ int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);

This is inconsistent with other uses of xen_feature(XENFEAT_auto_translated_physmap), so far xen_feature() has always been used.

unsigned long pfn;
int ret;
@@ -116,7 +121,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
continue;
frame = mfn;
} else {
- if (mfn != INVALID_P2M_ENTRY)
+ if (!xlated_phys && mfn != INVALID_P2M_ENTRY)
continue;
frame = pfn;
}
@@ -239,6 +244,27 @@ static void __init xen_set_identity_and_release_chunk(
*identity += set_phys_range_identity(start_pfn, end_pfn);
}
+/* For PVH, the pfns [0..MAX] are mapped to mfn's in the EPT/NPT. The mfns
+ * are released as part of this 1:1 mapping hypercall back to the dom heap.
+ * Also, we map the entire IO space, ie, beyond max_pfn_mapped.
+ */
+static void __init xen_pvh_identity_map_chunk(unsigned long start_pfn,
+ unsigned long end_pfn, unsigned long *released,
+ unsigned long *identity, unsigned long max_pfn)
+{
+ unsigned long pfn;
+ int numpfns = 1, add_mapping = 1;

No need for these two variables;

+
+ for (pfn = start_pfn; pfn < end_pfn; pfn++)
+ xen_set_clr_mmio_pvh_pte(pfn, pfn, numpfns, add_mapping);
+
+ if (start_pfn <= max_pfn) {
+ unsigned long end = min(max_pfn_mapped, end_pfn);
+ *released += end - start_pfn;
+ }
+ *identity += end_pfn - start_pfn;
+}
+
static unsigned long __init xen_set_identity_and_release(
const struct e820entry *list, size_t map_size, unsigned long nr_pages)
{
@@ -247,6 +273,7 @@ static unsigned long __init xen_set_identity_and_release(
unsigned long identity = 0;
const struct e820entry *entry;
int i;
+ int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);

Again xlated_phys.


-boris

/*
* Combine non-RAM regions and gaps until a RAM region (or the
@@ -268,11 +295,17 @@ static unsigned long __init xen_set_identity_and_release(
if (entry->type == E820_RAM)
end_pfn = PFN_UP(entry->addr);
- if (start_pfn < end_pfn)
- xen_set_identity_and_release_chunk(
- start_pfn, end_pfn, nr_pages,
- &released, &identity);
-
+ if (start_pfn < end_pfn) {
+ if (xlated_phys) {
+ xen_pvh_identity_map_chunk(start_pfn,
+ end_pfn, &released, &identity,
+ nr_pages);
+ } else {
+ xen_set_identity_and_release_chunk(
+ start_pfn, end_pfn, nr_pages,
+ &released, &identity);
+ }
+ }
start = end;
}
}
@@ -563,16 +596,13 @@ void xen_enable_nmi(void)
BUG();
#endif
}
-void __init xen_arch_setup(void)
+void __init xen_pvmmu_arch_setup(void)
{
- xen_panic_handler_init();
-
HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
- if (!xen_feature(XENFEAT_auto_translated_physmap))
- HYPERVISOR_vm_assist(VMASST_CMD_enable,
- VMASST_TYPE_pae_extended_cr3);
+ HYPERVISOR_vm_assist(VMASST_CMD_enable,
+ VMASST_TYPE_pae_extended_cr3);
if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
@@ -581,6 +611,15 @@ void __init xen_arch_setup(void)
xen_enable_sysenter();
xen_enable_syscall();
xen_enable_nmi();
+}
+
+/* This function not called for HVM domain */
+void __init xen_arch_setup(void)
+{
+ xen_panic_handler_init();
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ xen_pvmmu_arch_setup();
#ifdef CONFIG_ACPI
if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
printk(KERN_INFO "ACPI in unprivileged domain disabled\n");

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