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authorLan Tianyu <tianyu.lan@intel.com>2016-03-13 11:10:27 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2016-03-22 16:38:32 +0100
commit7bfdf2177812c30928bea3fc8bc86b9dea236f65 (patch)
treee223ff4e6069fa945c19c3e0be5d5393abf2376c
parenta30a0509165d9bc5a3107894338e6adf4be7b60f (diff)
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: Lan Tianyu <tianyu.lan@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/paging_tmpl.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index e0c225421157..1d971c7553c3 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -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;
}