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From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>,
	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 17:27:01 +0100	[thread overview]
Message-ID: <20160218162701.GB6289@potion.brq.redhat.com> (raw)
In-Reply-To: <56C5E8E1.9060900@redhat.com>

2016-02-18 16:53+0100, Paolo Bonzini:
> Patch 9 is okay, but it is also necessary to clear IsRunning in
> kvm_arch_vcpu_blocking and set it in kvm_arch_vcpu_unblocking.  In
> addition, vcpu_put/vcpu_load should not modify IsRunning between
> kvm_arch_vcpu_blocking and kvm_arch_vcpu_unblocking.  Do you agree?

Yes.

I think we don't need to clear IsRunning on preemption, which would
simplify the protection.  (I haven't thought much about userspace exit,
so maybe we could skip that one as well, but we don't need to now.)

The reason for that is that KVM knows that the VCPU was scheduled out,
so it couldn't do much in the AVIC VMEXIT.
(KVM could force scheduler to pritioritize the VCPU, but our kick
 doesn't do that now and it seems like a bad idea.)

Does it seem reasonable?

  reply	other threads:[~2016-02-18 16:27 UTC|newest]

Thread overview: 51+ 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
2016-02-18  2:25               ` Suravee Suthikulpanit
2016-02-18 14:18                 ` Radim Krčmář
2016-02-18 14:51                   ` Paolo Bonzini
2016-02-18 15:43                     ` Radim Krčmář
2016-02-18 15:53                       ` Paolo Bonzini
2016-02-18 16:27                         ` Radim Krčmář [this message]
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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