[PATCH 3/3] KVM: Add flush_on_enter before guest enter

[Wanpeng Li]

From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>

PV-Flush guest would indicate to flush on enter, flush the TLB before
entering and exiting the guest.

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1ea28a2..f295360 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2116,7 +2116,13 @@ static void record_steal_time(struct kvm_vcpu *vcpu)
 		&vcpu->arch.st.steal, sizeof(struct kvm_steal_time))))
 		return;
 
-	vcpu->arch.st.steal.preempted = KVM_VCPU_NOT_PREEMPTED;
+	if (xchg(&vcpu->arch.st.steal.preempted, KVM_VCPU_NOT_PREEMPTED) ==
+			(KVM_VCPU_SHOULD_FLUSH | KVM_VCPU_PREEMPTED))
+		/*
+		 * Do TLB_FLUSH before entering the guest, its passed
+		 * the stage of request checking
+		 */
+		kvm_x86_ops->tlb_flush(vcpu);
 
 	if (vcpu->arch.st.steal.version & 1)
 		vcpu->arch.st.steal.version += 1;  /* first time write, random junk */
@@ -2887,7 +2893,9 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
 	if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED))
 		return;
 
-	vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED;
+	if (xchg(&vcpu->arch.st.steal.preempted, KVM_VCPU_PREEMPTED) ==
+				KVM_VCPU_SHOULD_FLUSH)
+		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 
 	kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,
 			&vcpu->arch.st.steal.preempted,
-- 
2.7.4