[PATCH 2/6] kvm/mmu: rename is_largepage_backed to mapping_level

From: Joerg Roedel
Date: Tue Jul 07 2009 - 12:43:13 EST

With the new name and the corresponding backend changes this function
can now support multiple hugepage sizes.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
arch/x86/kvm/mmu.c | 100 +++++++++++++++++++++++++++++--------------
arch/x86/kvm/paging_tmpl.h | 4 +-
2 files changed, 69 insertions(+), 35 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0434990..7de9f41 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -393,37 +393,52 @@ static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
* Return the pointer to the largepage write count for a given
* gfn, handling slots that are not large page aligned.
*/
-static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
+static int *slot_largepage_idx(gfn_t gfn,
+ struct kvm_memory_slot *slot,
+ int level)
{
unsigned long idx;

- idx = (gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL)) -
- (slot->base_gfn / KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL));
- return &slot->lpage_info[0][idx].write_count;
+ idx = (gfn / KVM_PAGES_PER_HPAGE(level)) -
+ (slot->base_gfn / KVM_PAGES_PER_HPAGE(level));
+ return &slot->lpage_info[level - 2][idx].write_count;
}

static void account_shadowed(struct kvm *kvm, gfn_t gfn)
{
+ struct kvm_memory_slot *slot;
int *write_count;
+ int i;

gfn = unalias_gfn(kvm, gfn);
- write_count = slot_largepage_idx(gfn,
- gfn_to_memslot_unaliased(kvm, gfn));
- *write_count += 1;
+
+ slot = gfn_to_memslot_unaliased(kvm, gfn);
+ for (i = PT_DIRECTORY_LEVEL;
+ i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
+ write_count = slot_largepage_idx(gfn, slot, i);
+ *write_count += 1;
+ }
}

static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
{
+ struct kvm_memory_slot *slot;
int *write_count;
+ int i;

gfn = unalias_gfn(kvm, gfn);
- write_count = slot_largepage_idx(gfn,
- gfn_to_memslot_unaliased(kvm, gfn));
- *write_count -= 1;
- WARN_ON(*write_count < 0);
+ for (i = PT_DIRECTORY_LEVEL;
+ i < PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES; ++i) {
+ slot = gfn_to_memslot_unaliased(kvm, gfn);
+ write_count = slot_largepage_idx(gfn, slot, i);
+ *write_count -= 1;
+ WARN_ON(*write_count < 0);
+ }
}

-static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
+static int has_wrprotected_page(struct kvm *kvm,
+ gfn_t gfn,
+ int level)
{
struct kvm_memory_slot *slot;
int *largepage_idx;
@@ -431,47 +446,67 @@ static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
gfn = unalias_gfn(kvm, gfn);
slot = gfn_to_memslot_unaliased(kvm, gfn);
if (slot) {
- largepage_idx = slot_largepage_idx(gfn, slot);
+ largepage_idx = slot_largepage_idx(gfn, slot, level);
return *largepage_idx;
}

return 1;
}

-static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
+static int host_mapping_level(struct kvm *kvm, gfn_t gfn)
{
+ unsigned long page_size = PAGE_SIZE;
struct vm_area_struct *vma;
unsigned long addr;
- int ret = 0;
+ int i, ret = 0;

addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr))
- return ret;
+ return page_size;

down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, addr);
- if (vma && is_vm_hugetlb_page(vma))
- ret = 1;
+ if (!vma)
+ goto out;
+
+ page_size = vma_kernel_pagesize(vma);
+
+out:
up_read(&current->mm->mmap_sem);

+ for (i = PT_PAGE_TABLE_LEVEL;
+ i < (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES); ++i) {
+ if (page_size >= KVM_HPAGE_SIZE(i))
+ ret = i;
+ else
+ break;
+ }
+
return ret;
}

-static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
+static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
{
struct kvm_memory_slot *slot;
-
- if (has_wrprotected_page(vcpu->kvm, large_gfn))
- return 0;
-
- if (!host_largepage_backed(vcpu->kvm, large_gfn))
- return 0;
+ int host_level;
+ int level = PT_PAGE_TABLE_LEVEL;

slot = gfn_to_memslot(vcpu->kvm, large_gfn);
if (slot && slot->dirty_bitmap)
- return 0;
+ return PT_PAGE_TABLE_LEVEL;

- return 1;
+ host_level = host_mapping_level(vcpu->kvm, large_gfn);
+
+ if (host_level == PT_PAGE_TABLE_LEVEL)
+ return host_level;
+
+ for (level = PT_DIRECTORY_LEVEL; level <= host_level; ++level) {
+
+ if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
+ break;
+ }
+
+ return level - 1;
}

/*
@@ -1712,7 +1747,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if ((pte_access & ACC_WRITE_MASK)
|| (write_fault && !is_write_protection(vcpu) && !user_fault)) {

- if (largepage && has_wrprotected_page(vcpu->kvm, gfn)) {
+ if (largepage && has_wrprotected_page(vcpu->kvm, gfn, 1)) {
ret = 1;
spte = shadow_trap_nonpresent_pte;
goto set_pte;
@@ -1860,8 +1895,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
pfn_t pfn;
unsigned long mmu_seq;

- if (is_largepage_backed(vcpu, gfn &
- ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1))) {
+ if (mapping_level(vcpu, gfn) == PT_DIRECTORY_LEVEL) {
gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
largepage = 1;
}
@@ -2067,8 +2101,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
if (r)
return r;

- if (is_largepage_backed(vcpu, gfn &
- ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1))) {
+ if (mapping_level(vcpu, gfn) == PT_DIRECTORY_LEVEL) {
gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
largepage = 1;
}
@@ -2470,7 +2503,8 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
return;
gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;

- if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
+ if (is_large_pte(gpte) &&
+ (mapping_level(vcpu, gfn) == PT_DIRECTORY_LEVEL)) {
gfn &= ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
vcpu->arch.update_pte.largepage = 1;
}
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 36ac6d7..44f0346 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -407,8 +407,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
if (walker.level == PT_DIRECTORY_LEVEL) {
gfn_t large_gfn;
large_gfn = walker.gfn &
- ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
- if (is_largepage_backed(vcpu, large_gfn)) {
+ ~(KVM_PAGES_PER_HPAGE(PT_DIRECTORY_LEVEL) - 1);
+ if (mapping_level(vcpu, large_gfn) == PT_DIRECTORY_LEVEL) {
walker.gfn = large_gfn;
largepage = 1;
}
--
1.6.3.3


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