We just need flush tlb if overwrite a writable spte with a read-only one
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 4b6d54c..1a93ab4 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2044,6 +2044,15 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if (pte_access & ACC_WRITE_MASK)
mark_page_dirty(vcpu->kvm, gfn);
+ /*
+ * If we overwrite a writable spte with a read-only one,
+ * flush remote TLBs. Otherwise rmap_write_protect will
+ * find a read-only spte, even though the writable spte
+ * might be cached on a CPU's TLB.
+ */
+ else if (is_writable_pte(*sptep))
+ ret = 1;
+
set_pte:
update_spte(sptep, spte);
done:
@@ -2084,16 +2093,6 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
spte_to_pfn(*sptep), pfn);
drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
kvm_flush_remote_tlbs(vcpu->kvm);
- /*
- * If we overwrite a writable spte with a read-only one,
- * drop it and flush remote TLBs. Otherwise rmap_write_protect
- * will find a read-only spte, even though the writable spte
- * might be cached on a CPU's TLB.
- */
- } else if (is_writable_pte(*sptep) &&
- (!(pte_access & ACC_WRITE_MASK) || !dirty)) {
- drop_spte(vcpu->kvm, sptep, shadow_trap_nonpresent_pte);
- kvm_flush_remote_tlbs(vcpu->kvm);
} else
was_rmapped = 1;
}
--
1.7.0.4
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