Message-ID: <4A1FF6B9.9050502@siemens.com>
Date: Fri, 29 May 2009 16:52:41 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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References: <4A1F9B7C.4020201@siemens.com> <20090529130806.GB28542@redhat.com>
In-Reply-To: <20090529130806.GB28542@redhat.com>
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Subject: [Qemu-devel] Re: Lost interrupts with upstream KVM
To: Gleb Natapov <gleb@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>, kvm-devel <kvm@vger.kernel.org>

Gleb Natapov wrote:
> On Fri, May 29, 2009 at 10:23:24AM +0200, Jan Kiszka wrote:
>> Hi Gleb,
>>
>> with latest kernel modules, namely beginning with 6bc0a1a235 (Remove
>> irq_pending bitmap), I'm loosing interrupts with upstream's KVM support.
>> After some bisecting, hair-pulling and a bit meditation I added a
>> WARN_ON(kvm_cpu_has_interrupt(vcpu)) to kvm_vcpu_ioctl_interrupt, and it
>> actually triggered right before the guest got stuck.
>>
>> This didn't trigger with qemu-kvm (and -no-kvm-irqchip) yet but, on the
>> other hand, I currently do not see a potential bug in upstream's
>> kvm_arch_pre_run. Could you have a look if you can reproduce,
>> specifically if this isn't a KVM kernel issue in the end?
>>
> In kvm_cpu_exec() after calling kvm_arch_pre_run() env->exit_request is
> tested and function can exit without calling kvm_vcpu_ioctl(KVM_RUN).
> Can you check if this what happens in your case?

This path is executed quite frequently here. No obvious correlation with
the lost IRQ.

Jan

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