[PATCH 3/5] KVM: x86: MMU: Merge mapping_level_dirty_bitmap() into mapping_level()

Takuya Yoshikawa
2015-10-16T07:53:07Z

This is necessary to eliminate an extra memory slot search later.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
---
arch/x86/kvm/mmu.c | 29 ++++++++++++++---------------
arch/x86/kvm/paging_tmpl.h | 6 +++---
2 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2262728..890cd69 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -870,10 +870,16 @@ static bool mapping_level_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t large_gfn)
return !gfn_to_memslot_dirty_bitmap(vcpu, large_gfn, true);
}

-static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
+static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn,
+ bool *force_pt_level)
{
int host_level, level, max_level;

+ if (likely(!*force_pt_level))
+ *force_pt_level = mapping_level_dirty_bitmap(vcpu, large_gfn);
+ if (unlikely(*force_pt_level))
+ return PT_PAGE_TABLE_LEVEL;
+
host_level = host_mapping_level(vcpu->kvm, large_gfn);

if (host_level == PT_PAGE_TABLE_LEVEL)
@@ -2962,14 +2968,13 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
{
int r;
int level;
- bool force_pt_level;
+ bool force_pt_level = false;
pfn_t pfn;
unsigned long mmu_seq;
bool map_writable, write = error_code & PFERR_WRITE_MASK;

- force_pt_level = mapping_level_dirty_bitmap(vcpu, gfn);
+ level = mapping_level(vcpu, gfn, &force_pt_level);
if (likely(!force_pt_level)) {
- level = mapping_level(vcpu, gfn);
/*
* This path builds a PAE pagetable - so we can map
* 2mb pages at maximum. Therefore check if the level
@@ -2979,8 +2984,7 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
level = PT_DIRECTORY_LEVEL;

gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
- } else
- level = PT_PAGE_TABLE_LEVEL;
+ }

if (fast_page_fault(vcpu, v, level, error_code))
return 0;
@@ -3495,20 +3499,15 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
if (r)
return r;

- if (mapping_level_dirty_bitmap(vcpu, gfn) ||
- !check_hugepage_cache_consistency(vcpu, gfn, PT_DIRECTORY_LEVEL))
- force_pt_level = true;
- else
- force_pt_level = false;
-
+ force_pt_level = !check_hugepage_cache_consistency(vcpu, gfn,
+ PT_DIRECTORY_LEVEL);
+ level = mapping_level(vcpu, gfn, &force_pt_level);
if (likely(!force_pt_level)) {
- level = mapping_level(vcpu, gfn);
if (level > PT_DIRECTORY_LEVEL &&
!check_hugepage_cache_consistency(vcpu, gfn, level))
level = PT_DIRECTORY_LEVEL;
gfn &= ~(KVM_PAGES_PER_HPAGE(level) - 1);
- } else
- level = PT_PAGE_TABLE_LEVEL;
+ }

if (fast_page_fault(vcpu, gpa, level, error_code))
return 0;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 8ebc3a5..bf39d0f 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -744,9 +744,9 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
&walker, user_fault, &vcpu->arch.write_fault_to_shadow_pgtable);

if (walker.level >= PT_DIRECTORY_LEVEL && !is_self_change_mapping) {
- force_pt_level = mapping_level_dirty_bitmap(vcpu, walker.gfn);
- if (!force_pt_level) {
- level = min(walker.level, mapping_level(vcpu, walker.gfn));
+ level = mapping_level(vcpu, walker.gfn, &force_pt_level);
+ if (likely(!force_pt_level)) {
+ level = min(walker.level, level);
walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
}
} else
--
2.1.0