From: Peter Xu <peterx@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Alex Williamson <alex.williamson@redhat.com>,
Pei Zhang <pezhang@redhat.com>
Subject: Re: [patch 4/4] KVM: VMX: update vcpu posted-interrupt descriptor when assigning device
Date: Fri, 7 May 2021 15:29:05 -0400 [thread overview]
Message-ID: <YJWVAcIsvCaD7U0C@t490s> (raw)
In-Reply-To: <YJV3P4mFA7pITziM@google.com>
On Fri, May 07, 2021 at 05:22:07PM +0000, Sean Christopherson wrote:
> On Fri, May 07, 2021, Marcelo Tosatti wrote:
> > Index: kvm/arch/x86/kvm/vmx/posted_intr.c
> > ===================================================================
> > --- kvm.orig/arch/x86/kvm/vmx/posted_intr.c
> > +++ kvm/arch/x86/kvm/vmx/posted_intr.c
> > @@ -203,6 +203,25 @@ void pi_post_block(struct kvm_vcpu *vcpu
> > local_irq_enable();
> > }
> >
> > +int vmx_vcpu_check_block(struct kvm_vcpu *vcpu)
> > +{
> > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu);
> > +
> > + if (!irq_remapping_cap(IRQ_POSTING_CAP))
> > + return 0;
> > +
> > + if (!kvm_vcpu_apicv_active(vcpu))
> > + return 0;
> > +
> > + if (!kvm_arch_has_assigned_device(vcpu->kvm))
> > + return 0;
> > +
> > + if (pi_desc->nv == POSTED_INTR_WAKEUP_VECTOR)
> > + return 0;
> > +
> > + return 1;
>
> IIUC, the logic is to bail out of the block loop if the VM has an assigned
> device, but the blocking vCPU didn't reconfigure the PI.NV to the wakeup vector,
> i.e. the assigned device came along after the initial check in vcpu_block().
> That makes sense, but you can add a comment somewhere in/above this function?
Wondering whether we should add a pi_test_on() check in kvm_vcpu_has_events()
somehow, so that even without customized ->vcpu_check_block we should be able
to break the block loop (as kvm_arch_vcpu_runnable will return true properly)?
--
Peter Xu
next prev parent reply other threads:[~2021-05-07 19:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 13:06 [patch 0/4] VMX: configure posted interrupt descriptor when assigning device Marcelo Tosatti
2021-05-07 13:06 ` [patch 1/4] KVM: x86: add start_assignment hook to kvm_x86_ops Marcelo Tosatti
2021-05-07 19:16 ` Peter Xu
2021-05-10 17:53 ` Marcelo Tosatti
2021-05-07 13:06 ` [patch 2/4] KVM: add arch specific vcpu_check_block callback Marcelo Tosatti
2021-05-07 13:06 ` [patch 3/4] KVM: x86: implement kvm_arch_vcpu_check_block callback Marcelo Tosatti
2021-05-07 13:06 ` [patch 4/4] KVM: VMX: update vcpu posted-interrupt descriptor when assigning device Marcelo Tosatti
2021-05-07 17:22 ` Sean Christopherson
2021-05-07 19:29 ` Peter Xu [this message]
2021-05-07 22:08 ` Marcelo Tosatti
2021-05-11 14:39 ` Peter Xu
2021-05-11 14:51 ` Marcelo Tosatti
2021-05-11 16:19 ` Peter Xu
2021-05-11 17:18 ` Marcelo Tosatti
2021-05-11 21:35 ` Peter Xu
2021-05-11 23:51 ` Marcelo Tosatti
2021-05-12 0:02 ` Marcelo Tosatti
2021-05-12 0:38 ` Peter Xu
2021-05-12 11:10 ` Marcelo Tosatti
2021-05-12 14:41 ` Sean Christopherson
2021-05-12 15:34 ` Peter Xu
-- strict thread matches above, loose matches on Subject: below --
2021-05-10 17:26 [patch 0/4] VMX: configure posted interrupt descriptor when assigning device (v3) Marcelo Tosatti
2021-05-10 17:26 ` [patch 4/4] KVM: VMX: update vcpu posted-interrupt descriptor when assigning device Marcelo Tosatti
2021-05-24 15:55 ` Paolo Bonzini
2021-05-24 17:53 ` Marcelo Tosatti
2021-05-25 11:58 ` Paolo Bonzini
2021-05-11 23:57 [patch 0/4] VMX: configure posted interrupt descriptor when assigning device (v4) Marcelo Tosatti
2021-05-11 23:57 ` [patch 4/4] KVM: VMX: update vcpu posted-interrupt descriptor when assigning device Marcelo Tosatti
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