KVM: MMU: Reinstate pte prefetch on invlpg

[safe/jmp/linux-2.6] / arch / x86 / kvm / mmu.c

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 91f8b17..064c3ef 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2613,20 +2613,11 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
        int flooded = 0;
        int npte;
        int r;
+       int invlpg_counter;
 
        pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
 
-       switch (bytes) {
-       case 4:
-               gentry = *(const u32 *)new;
-               break;
-       case 8:
-               gentry = *(const u64 *)new;
-               break;
-       default:
-               gentry = 0;
-               break;
-       }
+       invlpg_counter = atomic_read(&vcpu->kvm->arch.invlpg_counter);
 
        /*
         * Assume that the pte write on a page table of the same type
@@ -2634,16 +2625,34 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
         * (might be false while changing modes).  Note it is verified later
         * by update_pte().
         */
-       if (is_pae(vcpu) && bytes == 4) {
+       if ((is_pae(vcpu) && bytes == 4) || !new) {
                /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
-               gpa &= ~(gpa_t)7;
-               r = kvm_read_guest(vcpu->kvm, gpa, &gentry, 8);
+               if (is_pae(vcpu)) {
+                       gpa &= ~(gpa_t)7;
+                       bytes = 8;
+               }
+               r = kvm_read_guest(vcpu->kvm, gpa, &gentry, min(bytes, 8));
                if (r)
                        gentry = 0;
+               new = (const u8 *)&gentry;
+       }
+
+       switch (bytes) {
+       case 4:
+               gentry = *(const u32 *)new;
+               break;
+       case 8:
+               gentry = *(const u64 *)new;
+               break;
+       default:
+               gentry = 0;
+               break;
        }
 
        mmu_guess_page_from_pte_write(vcpu, gpa, gentry);
        spin_lock(&vcpu->kvm->mmu_lock);
+       if (atomic_read(&vcpu->kvm->arch.invlpg_counter) != invlpg_counter)
+               gentry = 0;
        kvm_mmu_access_page(vcpu, gfn);
        kvm_mmu_free_some_pages(vcpu);
        ++vcpu->kvm->stat.mmu_pte_write;