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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: mtosatti@redhat.com, Davide Libenzi <davidel@xmailserver.org>,
	kvm@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
Date: Wed, 20 Jan 2010 16:58:22 +0200	[thread overview]
Message-ID: <20100120145822.GB3434@redhat.com> (raw)
In-Reply-To: <4B570EDD.6000808@redhat.com>

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
crashes.



-- 
MST

  reply	other threads:[~2010-01-20 15:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-13 17:12 [PATCH 0/2] kvm: fix spurious interrupt with irqfd Michael S. Tsirkin
2010-01-17 12:42 ` Avi Kivity
2010-01-19 14:52   ` Michael S. Tsirkin
2010-01-20 14:10     ` Avi Kivity
2010-01-20 14:58       ` Michael S. Tsirkin [this message]
2010-01-20 15:09         ` Avi Kivity
2010-01-20 15:09           ` Michael S. Tsirkin
2010-01-20 17:19       ` Davide Libenzi

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