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Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip
From: |
Marcelo Tosatti |
Subject: |
Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip |
Date: |
Thu, 3 Feb 2011 08:04:07 -0200 |
User-agent: |
Mutt/1.5.20 (2009-08-17) |
On Thu, Feb 03, 2011 at 10:32:25AM +0100, Jan Kiszka wrote:
> On 2011-02-03 09:18, Avi Kivity wrote:
> > On 02/02/2011 05:52 PM, Jan Kiszka wrote:
> >>>>
> >>> If there is no problem in the logic of this commit (and I do not see
> >>> one yet) then we somewhere miss kicking vcpu when interrupt, that should
> >>> be
> >>> handled, arrives?
> >>
> >> I'm not yet confident about the logic of the kernel patch: mov to cr8 is
> >> serializing. If the guest raises the tpr and then signals this with a
> >> succeeding, non vm-exiting instruction to the other vcpus, one of those
> >> could inject an interrupt with a higher priority than the previous tpr,
> >> but a lower one than current tpr. QEMU user space would accept this
> >> interrupt - and would likely surprise the guest. Do I miss something?
> >
> > apic_get_interrupt() is only called from the vcpu thread, so it should
> > see a correct tpr.
> >
> > The only difference I can see with the patch is that we may issue a
> > spurious cpu_interrupt(). But that shouldn't do anything bad, should it?
>
> I tested this yesterday, and it doesn't confuse Windows. It actually
> receives quite a few spurious IRQs in normal operation, w/ or w/o the
> kernel's tpr optimization.
http://www.mail-archive.com/address@hidden/msg41681.html
tpr of a vcpu should always be inspected in vcpu context, instead of
iothread context?
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, (continued)
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Gleb Natapov, 2011/02/02
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/02
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Gleb Natapov, 2011/02/02
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/02
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Gleb Natapov, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Avi Kivity, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Avi Kivity, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip,
Marcelo Tosatti <=
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Gleb Natapov, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Jan Kiszka, 2011/02/03
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Avi Kivity, 2011/02/06
- Re: [Qemu-devel] KVM: Windows 64-bit troubles with user space irqchip, Gleb Natapov, 2011/02/06