On 09/11/2017 03:02, Wanpeng Li wrote: > 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 Krčmář <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); This is not necessary. Instead, you can just OR the KVM_VCPU_PREEMPTED bit; record_steal_time will pick up the request and do the TLB flush later. Also, I think this is a case where you should prefer INVVPID to INVEP. That's because "execution of the INVEPT instruction invalidates guest-physical mappings and combined mappings" while "execution of the INVVPID instruction invalidates linear mappings and combined mappings". In this case, invalidating guest-physical mapping is unnecessary. So you could add a new bool argument to kvm_x86_ops->tlb_flush. In vmx.c, __vmx_flush_tlb can do invept if "enable_ept && (invalidate_gpa || !enable_vpid)". If !enable_ept && !enable_vpid, the feature cannot be made available. Thanks, Paolo > kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime, > &vcpu->arch.st.steal.preempted, >
