From: Paolo Bonzini <pbonzini@redhat.com>
To: "Radim Krčmář" <rkrcmar@redhat.com>,
"Suravee Suthikulpanit" <Suravee.Suthikulpanit@amd.com>
Cc: joro@8bytes.org, alex.williamson@redhat.com, gleb@kernel.org,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
wei@redhat.com, sherry.hurwitz@amd.com
Subject: Re: [PART1 RFC 5/9] svm: Add VMEXIT handlers for AVIC
Date: Thu, 18 Feb 2016 15:51:14 +0100 [thread overview]
Message-ID: <56C5DA62.8080204@redhat.com> (raw)
In-Reply-To: <20160218141817.GA6289@potion.brq.redhat.com>
On 18/02/2016 15:18, Radim Krčmář wrote:
> KVM just has to make sure that targeted VCPUs notice the interrupt,
> which means to kick (wake up) VCPUs that don't have IsRunning set.
> There is no need to do anything with running VCPUs, because they
> - are in guest mode and noticed the doorbell
> - are in host mode, where they will
> 1) VMRUN as fast as they can because the VCPU didn't want to halt
> (and IRR is handled on VMRUN)
> 2) check IRR after unsetting IsRunning and goto (1) if there are
> pending interrupts. (RFC doesn't do this, which is another bug)
This is not necessary. IsRunning is only cleared at vcpu_put time. The
next KVM_RUN will look at IRR (kvm_arch_vcpu_runnable), if necessary set
the mp_state to KVM_MP_STATE_RUNNABLE, and do the VMRUN.
But I agree that this is what Suravee is missing.
> It's still possible that we misunderstood the spec. Does AVIC handle
> IPIs differently?
I don't think we misunderstood it. Well, I did, but that's fixed now. :)
Paolo
next prev parent reply other threads:[~2016-02-18 14:51 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-12 13:59 [PART1 RFC 0/9] KVM: x86: Introduce SVM AVIC support Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 1/9] KVM: x86: Misc LAPIC changes to exposes helper functions Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 2/9] svm: Introduce new AVIC VMCB registers Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 3/9] svm: clean up V_TPR, V_IRQ, V_INTR_PRIO, and V_INTR_MASKING Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 4/9] KVM: x86: Detect and Initialize AVIC support Suravee Suthikulpanit
2016-02-12 14:13 ` Borislav Petkov
2016-02-12 15:46 ` Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 5/9] svm: Add VMEXIT handlers for AVIC Suravee Suthikulpanit
2016-02-12 15:38 ` Paolo Bonzini
2016-02-15 19:22 ` Radim Krčmář
2016-02-16 6:29 ` Suravee Suthikulpanit
2016-02-16 12:15 ` Paolo Bonzini
2016-02-16 14:13 ` Radim Krčmář
2016-02-16 16:56 ` Paolo Bonzini
2016-02-16 18:06 ` Radim Krčmář
2016-02-16 18:06 ` Radim Krčmář
2016-02-18 2:25 ` Suravee Suthikulpanit
2016-02-18 14:18 ` Radim Krčmář
2016-02-18 14:51 ` Paolo Bonzini [this message]
2016-02-18 15:43 ` Radim Krčmář
2016-02-18 15:53 ` Paolo Bonzini
2016-02-18 16:27 ` Radim Krčmář
2016-02-18 17:18 ` Paolo Bonzini
2016-02-19 11:39 ` Suravee Suthikulpanit
2016-02-19 11:44 ` Paolo Bonzini
2016-02-19 11:59 ` Suravee Suthikulpanit
2016-03-03 10:42 ` Suravee Suthikulpanit
2016-03-03 10:50 ` Paolo Bonzini
2016-02-19 11:32 ` Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 6/9] svm: Add interrupt injection via AVIC Suravee Suthikulpanit
2016-02-12 14:16 ` Borislav Petkov
2016-02-12 15:54 ` Suravee Suthikulpanit
2016-02-12 17:14 ` Borislav Petkov
2016-02-12 18:21 ` Paolo Bonzini
2016-02-12 18:30 ` Borislav Petkov
2016-02-12 18:56 ` Paolo Bonzini
2016-02-12 19:33 ` Borislav Petkov
2016-02-16 7:50 ` Ingo Molnar
2016-02-16 8:39 ` [PATCH] x86/msr: Document msr-index.h rule for addition Borislav Petkov
2016-02-12 15:55 ` [PART1 RFC 6/9] svm: Add interrupt injection via AVIC Paolo Bonzini
2016-02-12 16:21 ` Suravee Suthikulpanit
2016-02-12 18:19 ` Paolo Bonzini
2016-02-12 19:36 ` Suravee Suthikulpanit
2016-02-19 11:57 ` Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 7/9] svm: Do not expose x2APIC when enable AVIC Suravee Suthikulpanit
2016-02-12 13:59 ` [PART1 RFC 8/9] svm: Do not intercept CR8 " Suravee Suthikulpanit
2016-02-12 15:48 ` Paolo Bonzini
2016-02-12 13:59 ` [PART1 RFC 9/9] svm: Manage vcpu load/unload " Suravee Suthikulpanit
2016-02-12 15:46 ` Paolo Bonzini
2016-02-12 18:13 ` [PART1 RFC 0/9] KVM: x86: Introduce SVM AVIC support Paolo Bonzini
2016-02-12 19:55 ` Suravee Suthikulpanit
2016-02-12 20:05 ` Paolo Bonzini
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