KVM: MMU: prepopulate the shadow on invlpg

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>

1 files changed, 13 insertions, 12 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index cbac9e4b156f..863baf70506e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -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;
@@ -2467,15 +2468,17 @@ 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 (gfn == vcpu->arch.last_pt_write_gfn
-            && !last_updated_pte_accessed(vcpu)) {
-                ++vcpu->arch.last_pt_write_count;
-                if (vcpu->arch.last_pt_write_count >= 3)
-                        flooded = 1;
-        } else {
-                vcpu->arch.last_pt_write_gfn = gfn;
-                vcpu->arch.last_pt_write_count = 1;
-                vcpu->arch.last_pte_updated = NULL;
+        if (guest_initiated) {
+                if (gfn == vcpu->arch.last_pt_write_gfn
+                    && !last_updated_pte_accessed(vcpu)) {
+                        ++vcpu->arch.last_pt_write_count;
+                        if (vcpu->arch.last_pt_write_count >= 3)
+                                flooded = 1;
+                } else {
+                        vcpu->arch.last_pt_write_gfn = gfn;
+                        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];
@@ -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;
 }