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[Qemu-devel] Re: Lost interrupts with upstream KVM
From: |
Gleb Natapov |
Subject: |
[Qemu-devel] Re: Lost interrupts with upstream KVM |
Date: |
Fri, 29 May 2009 19:20:16 +0300 |
On Fri, May 29, 2009 at 04:52:41PM +0200, Jan Kiszka wrote:
> 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.
>
If kvm_arch_pre_run() injected interrupt kvm_vcpu_ioctl(KVM_RUN) have to
be executed before injecting another interrupt, so if on the fist call
of kvm_cpu_exec() kvm_arch_pre_run() injected interrupt, but
kvm_vcpu_ioctl(KVM_RUN) was not executed because of env->exit_request
and on the next kvm_cpu_exec() other interrupt is injected the previous
one will be lost.
--
Gleb.
- [Qemu-devel] Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Gleb Natapov, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Gleb Natapov, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM,
Gleb Natapov <=
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Gleb Natapov, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Gleb Natapov, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Gleb Natapov, 2009/05/29
- [Qemu-devel] Re: Lost interrupts with upstream KVM, Jan Kiszka, 2009/05/29