KVM: MMU: avoid double write protected in sync page path

The sync page is already write protected in mmu_sync_children(), don't
write protected it again

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index aa98fca03ed7..ff333572be75 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1216,6 +1216,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,
                 if ((sp)->gfn != (gfn) || (sp)->role.direct ||          \
                         (sp)->role.invalid) {} else
 
+/* @sp->gfn should be write-protected at the call site */
 static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
                            struct list_head *invalid_list, bool clear_unsync)
 {
@@ -1224,11 +1225,8 @@ static int __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
                 return 1;
         }
 
-        if (clear_unsync) {
-                if (rmap_write_protect(vcpu->kvm, sp->gfn))
-                        kvm_flush_remote_tlbs(vcpu->kvm);
+        if (clear_unsync)
                 kvm_unlink_unsync_page(vcpu->kvm, sp);
-        }
 
         if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
                 kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list);