KVM: MMU: do not record gfn in kvm_mmu_pte_write

No need to record the gfn to verifier the pte has the same mode as
current vcpu, it's because we only speculatively update the pte only
if the pte and vcpu have the same mode

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index d5455b1b725f..91a194667432 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3228,7 +3228,6 @@ static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
                 kvm_release_pfn_clean(pfn);
                 return;
         }
-        vcpu->arch.update_pte.gfn = gfn;
         vcpu->arch.update_pte.pfn = pfn;
 }
 
@@ -3275,9 +3274,8 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 
         /*
          * Assume that the pte write on a page table of the same type
-         * as the current vcpu paging mode.  This is nearly always true
-         * (might be false while changing modes).  Note it is verified later
-         * by update_pte().
+         * as the current vcpu paging mode since we update the sptes only
+         * when they have the same mode.
          */
         if ((is_pae(vcpu) && bytes == 4) || !new) {
                 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */