From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Jan Kiszka <jan.kiszka@siemens.com>,
Nobuo Yoshida <yoshida.nb@ncos.nec.co.jp>
Subject: Re: [PATCH v2] KVM: x86: Inject pending interrupt even if pending nmi exist
Date: Wed, 23 Mar 2016 18:21:59 +0100 [thread overview]
Message-ID: <20160323172159.GA22164@potion.brq.redhat.com> (raw)
In-Reply-To: <56F297A7.1030309@redhat.com>
2016-03-23 14:18+0100, Paolo Bonzini:
> On 23/03/2016 06:08, Yuki Shibuya wrote:
>> + /* If nmi pending > 0 and injectable interrupts exist,
>> + * nmi pending counter is cleared to prevent skipping
>> + * injectable pending interrupts.
>> + */
>> + if (vcpu->arch.nmi_pending && kvm_cpu_has_injectable_intr(vcpu)
>> + && kvm_x86_ops->interrupt_allowed(vcpu))
>> + vcpu->arch.nmi_pending = 0;
>
> I am not sure I understand this. Why is it safe to drop nmi_pending?
NMIs are latched (queue length 1) and therefore cannot be pending after
an injection. I think we want to do it unconditionally.
> Can we instead do something like this in vcpu_enter_guest?
(We should, even if it doesn't fix the bug. Maskable interrupts can be
injected while NMIs are blocked.)
What the hell is 2.6.32 doing, though?
next prev parent reply other threads:[~2016-03-23 17:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 5:08 [PATCH v2] KVM: x86: Inject pending interrupt even if pending nmi exist Yuki Shibuya
2016-03-23 13:18 ` Paolo Bonzini
2016-03-23 17:21 ` Radim Krčmář [this message]
2016-03-23 18:22 ` Paolo Bonzini
2016-03-23 19:04 ` Radim Krčmář
2016-03-23 21:00 ` Paolo Bonzini
2016-03-23 21:06 ` Jan Kiszka
2016-03-23 21:11 ` Paolo Bonzini
2016-03-23 21:55 ` Radim Krčmář
2016-03-24 5:08 ` Yuki Shibuya
2016-03-24 11:09 ` Paolo Bonzini
2016-03-23 21:52 ` Radim Krčmář
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