Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd

From: Michael S. Tsirkin
Date: Wed Jan 20 2010 - 10:01:35 EST

On Wed, Jan 20, 2010 at 04:10:37PM +0200, Avi Kivity wrote:
> On 01/19/2010 04:52 PM, Michael S. Tsirkin wrote:
>> On Sun, Jan 17, 2010 at 02:42:50PM +0200, Avi Kivity wrote:
>>> On 01/13/2010 07:12 PM, Michael S. Tsirkin wrote:
>>>> Deassigning irqfd and assigning back caused spurious interrupt. fix this
>>>> by clearing the counter on deassign. This is on top of davidel's patch
>>>> which makes clearing eventfd counter from modules possible.
>>> Applied both, thanks.
>> Hmm, I see this in kvm master. Avi/Marcelo, since this is a bugfix, can
>> you queue this patchset for 2.6.33 and 2.6.32 stable as well please?
> I'm uncomfortable with pushing Davide's patch into stable and possibly
> causing regressions with unrelated applications. Can't a guest live
> with a spurious interrupt?

Well guests mask/unmask vector on each interrupt, so this will trigger
an irq storm I think.

> It's not like they're unknown.

Depends on the device really.
In theory, if they trigger at an unfortunate time this could cause

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