From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liran Alon Subject: Re: [PATCH v2] x86/kvm/vmx: Don't halt vcpu when L1 is injecting events to L2 Date: Fri, 9 Feb 2018 16:31:22 -0800 (PST) Message-ID: <806c274d-5d9a-432a-bf04-f154be89cb7f@default> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: , , , , , , , To: Return-path: Received: from aserp2130.oracle.com ([141.146.126.79]:47786 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753300AbeBJAbl (ORCPT ); Fri, 9 Feb 2018 19:31:41 -0500 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: ----- chao.gao@intel.com wrote: > Although L2 is in halt state, it will be in the active state after > VM entry if the VM entry is vectoring according to SDM 26.6.2 > Activity > State. Halting the vcpu here means the event won't be injected to L2 > and this decision isn't reported to L1. Thus L0 drops an event that > should be injected to L2. >=20 > Cc: Liran Alon > Signed-off-by: Chao Gao > --- > Changes in v2: > - Remove VID stuff. Only handle event injection in this patch. > --- > arch/x86/kvm/vmx.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) >=20 > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index bb5b488..42f39d9 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -10985,7 +10985,12 @@ static int nested_vmx_run(struct kvm_vcpu > *vcpu, bool launch) > =09if (ret) > =09=09return ret; > =20 > -=09if (vmcs12->guest_activity_state =3D=3D GUEST_ACTIVITY_HLT) > +=09/* > +=09 * If we're entering a halted L2 vcpu and the L2 vcpu won't be > woken > +=09 * by event injection, halt vcpu for optimization. I would remove the "for optimization." from the comment. > +=09 */ > +=09if ((vmcs12->guest_activity_state =3D=3D GUEST_ACTIVITY_HLT) && > +=09 !(vmcs12->vm_entry_intr_info_field & > VECTORING_INFO_VALID_MASK)) VECTORING_INFO_VALID_MASK is used in KVM code against vmcs12->idt_vectoring= _info_field. I think you should use INTR_INFO_VALID_MASK to be consistent with rest of c= ode. > =09=09return kvm_vcpu_halt(vcpu); > =20 > =09vmx->nested.nested_run_pending =3D 1; > --=20 > 1.9.1 In addition, commit title should be written in format of: "KVM: VMX: Don't halt vcpu when L1 is injecting events to L2" (Makes it easier to grep in git log). Other than that, seems good to me. :) Reviewed-by: Liran Alon Thanks, -Liran