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Date: Wed, 14 Aug 2013 11:05:29 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: Re: [Qemu-devel] Using aio_poll for timer carrier threads
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To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel <qemu-devel@nongnu.org>, liu ping fan <qemulist@gmail.com>, Alex Bligh <alex@alex.org.uk>, Paolo Bonzini <pbonzini@redhat.com>, MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>, Richard Henderson <rth@twiddle.net>

On 2013-08-14 10:52, Stefan Hajnoczi wrote:
> On Tue, Aug 13, 2013 at 04:13:03PM +0200, Jan Kiszka wrote:
>> On 2013-08-13 15:45, Stefan Hajnoczi wrote:
>>> On Tue, Aug 13, 2013 at 09:56:17AM +0200, Jan Kiszka wrote:
>>> The details depend on your device, do you have a git repo I can look at
>>> to understand your device model?
>>
>> Pushed my hacks here:
>>
>> git://git.kiszka.org/qemu.git queues/rt.new3
> 
> Excellent, thanks!  Are you calling qemu_raise_irq() outside the global
> mutex and how is it protected?

By luck and via many exceptions, specifically by disabling of HPET
support (to avoid that it is involved in IRQ routing - or even used in
legacy mode) and by relying on the direct delivery to the kernel in KVM
mode. Yes, IRQ delivery is still a huge construction site for BQL-free
device models.

Jan

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