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Commit 7bfdf217 authored by Lan Tianyu's avatar Lan Tianyu Committed by Paolo Bonzini
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KVM/x86: Call smp_wmb() before increasing tlbs_dirty 



Update spte before increasing tlbs_dirty to make sure no tlb flush
in lost after spte is zapped. This pairs with the barrier in the
kvm_flush_remote_tlbs().

Signed-off-by: default avatarLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a30a0509

arch/x86/kvm/paging_tmpl.h

+11 −0
Original line number Diff line number Diff line
@@ -960,6 +960,12 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) 
			return 0;



		if (FNAME(prefetch_invalid_gpte)(vcpu, sp, &sp->spt[i], gpte)) {

			/*

			 * Update spte before increasing tlbs_dirty to make

			 * sure no tlb flush is lost after spte is zapped; see

			 * the comments in kvm_flush_remote_tlbs().

			 */

			smp_wmb();

			vcpu->kvm->tlbs_dirty++;

			continue;

		}
@@ -975,6 +981,11 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) 


		if (gfn != sp->gfns[i]) {

			drop_spte(vcpu->kvm, &sp->spt[i]);

			/*

			 * The same as above where we are doing

			 * prefetch_invalid_gpte().

			 */

			smp_wmb();

			vcpu->kvm->tlbs_dirty++;

			continue;

		}