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: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
arch/x86/kvm/paging_tmpl.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index e159a81..d34475e 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -949,6 +949,12 @@ 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 in lost after spte is zapped, see the
+ * comments in kvm_flush_remote_tlbs().
+ */
+ smp_wmb();
vcpu->kvm->tlbs_dirty++;
continue;
}
@@ -964,6 +970,11 @@ 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;
}
--
1.8.4.rc0.1.g8f6a3e5.dirty
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