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Date: Fri, 11 Sep 2009 13:52:05 +0200
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: [Qemu-devel] Re: [COMMIT 733318e] don't call cpu_sychronize_state
 from reset handlers
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To: Glauber Costa <glommer@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>

Glauber Costa wrote:
> On Fri, Sep 11, 2009 at 01:15:49PM +0200, Jan Kiszka wrote:
>> Anthony Liguori wrote:
>>> From: Glauber Costa <glommer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>>
>>> Doing this will make the vcpu ioctl be issued from the I/O thread, instead
>>> of cpu thread. The correct behaviour is to call it from within the cpu thread,
>>> as soon as we are ready to go.
>> Note that in the good old days, this used to work properly (in qemu-kvm)
>> as registers write-back was routed through on_vcpu.
> 
> I believe we should avoid the use of those things, specially at initialization. They are
> totally racy and fragile. One way to do that, is to do all the reset functions inside the
> cpu thread.

As all this used to work fine in practice in upstream as well as in
qemu-kvm, I'm slightly unhappy about the current situation.

> 
> I already have something hacked up for this, will send as soon as I finish testing.

OK, looking forward.

BTW, what's the state of the fix for the guest-debug regression under KVM?

Jan

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