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KVM: MMU: prepopulate the shadow on invlpg

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If the guest executes invlpg, peek into the pagetable and attempt to
prepopulate the shadow entry.

Also stop dirty fault updates from interfering with the fork detector.

2% improvement on RHEL3/AIM7.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Marcelo Tosatti 2008-12-01 22:32:05 -02:00 committed by Avi Kivity
parent 6cffe8ca4a
commit ad218f85e3
4 changed files with 40 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/include/asm/kvm_host.h
View File

@ -602,7 +602,8 @@ unsigned long segment_base(u16 selector);
void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu);
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes);
const u8 *new, int bytes,
bool guest_initiated);
int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva);
void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu);
int kvm_mmu_load(struct kvm_vcpu *vcpu);

7
arch/x86/kvm/mmu.c
View File

@ -2441,7 +2441,8 @@ static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
}
void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
const u8 *new, int bytes)
const u8 *new, int bytes,
bool guest_initiated)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
struct kvm_mmu_page *sp;
@ -2467,6 +2468,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
kvm_mmu_free_some_pages(vcpu);
++vcpu->kvm->stat.mmu_pte_write;
kvm_mmu_audit(vcpu, "pre pte write");
if (guest_initiated) {
if (gfn == vcpu->arch.last_pt_write_gfn
&& !last_updated_pte_accessed(vcpu)) {
++vcpu->arch.last_pt_write_count;
@ -2477,6 +2479,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
vcpu->arch.last_pt_write_count = 1;
vcpu->arch.last_pte_updated = NULL;
}
}
index = kvm_page_table_hashfn(gfn);
bucket = &vcpu->kvm->arch.mmu_page_hash[index];
hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
@ -2615,9 +2618,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
spin_lock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.invlpg(vcpu, gva);
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_mmu_flush_tlb(vcpu);
++vcpu->stat.invlpg;
}

25
arch/x86/kvm/paging_tmpl.h
View File

@ -82,6 +82,7 @@ struct shadow_walker {
int *ptwrite;
pfn_t pfn;
u64 *sptep;
gpa_t pte_gpa;
};
static gfn_t gpte_to_gfn(pt_element_t gpte)
@ -222,7 +223,7 @@ walk:
if (ret)
goto walk;
pte |= PT_DIRTY_MASK;
kvm_mmu_pte_write(vcpu, pte_gpa, (u8 *)&pte, sizeof(pte));
kvm_mmu_pte_write(vcpu, pte_gpa, (u8 *)&pte, sizeof(pte), 0);
walker->ptes[walker->level - 1] = pte;
}
@ -468,8 +469,15 @@ static int FNAME(shadow_invlpg_entry)(struct kvm_shadow_walk *_sw,
struct kvm_vcpu *vcpu, u64 addr,
u64 *sptep, int level)
{
struct shadow_walker *sw =
container_of(_sw, struct shadow_walker, walker);
if (level == PT_PAGE_TABLE_LEVEL) {
struct kvm_mmu_page *sp = page_header(__pa(sptep));
sw->pte_gpa = (sp->gfn << PAGE_SHIFT);
sw->pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
if (is_shadow_present_pte(*sptep))
rmap_remove(vcpu->kvm, sptep);
set_shadow_pte(sptep, shadow_trap_nonpresent_pte);
@ -482,11 +490,26 @@ static int FNAME(shadow_invlpg_entry)(struct kvm_shadow_walk *_sw,
static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
{
pt_element_t gpte;
struct shadow_walker walker = {
.walker = { .entry = FNAME(shadow_invlpg_entry), },
.pte_gpa = -1,
};
spin_lock(&vcpu->kvm->mmu_lock);
walk_shadow(&walker.walker, vcpu, gva);
spin_unlock(&vcpu->kvm->mmu_lock);
if (walker.pte_gpa == -1)
return;
if (kvm_read_guest_atomic(vcpu->kvm, walker.pte_gpa, &gpte,
sizeof(pt_element_t)))
return;
if (is_present_pte(gpte) && (gpte & PT_ACCESSED_MASK)) {
if (mmu_topup_memory_caches(vcpu))
return;
kvm_mmu_pte_write(vcpu, walker.pte_gpa, (const u8 *)&gpte,
sizeof(pt_element_t), 0);
}
}
static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr)

2
arch/x86/kvm/x86.c
View File

@ -2046,7 +2046,7 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
ret = kvm_write_guest(vcpu->kvm, gpa, val, bytes);
if (ret < 0)
return 0;
kvm_mmu_pte_write(vcpu, gpa, val, bytes);
kvm_mmu_pte_write(vcpu, gpa, val, bytes, 1);
return 1;
}