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* [PATCH 0/2] kvm: fix spurious interrupt with irqfd
@ 2010-01-13 17:12 Michael S. Tsirkin
  2010-01-17 12:42 ` Avi Kivity
  0 siblings, 1 reply; 8+ messages in thread
From: Michael S. Tsirkin @ 2010-01-13 17:12 UTC (permalink / raw)
  To: Davide Libenzi, Michael S. Tsirkin, Avi Kivity, kvm,
	Linux Kernel Mailing List


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.

Michael S. Tsirkin (2):
  kvm: fix spurious interrupt with irqfd
  kvm: do not store wqh in irqfd

 virt/kvm/eventfd.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  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
  0 siblings, 1 reply; 8+ messages in thread
From: Avi Kivity @ 2010-01-17 12:42 UTC (permalink / raw)
  To: Michael S. Tsirkin; +Cc: Davide Libenzi, kvm, Linux Kernel Mailing List

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.

-- 
error compiling committee.c: too many arguments to function


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-17 12:42 ` Avi Kivity
@ 2010-01-19 14:52   ` Michael S. Tsirkin
  2010-01-20 14:10     ` Avi Kivity
  0 siblings, 1 reply; 8+ messages in thread
From: Michael S. Tsirkin @ 2010-01-19 14:52 UTC (permalink / raw)
  To: Avi Kivity, mtosatti; +Cc: Davide Libenzi, kvm, Linux Kernel Mailing List

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?

> -- 
> error compiling committee.c: too many arguments to function

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-19 14:52   ` Michael S. Tsirkin
@ 2010-01-20 14:10     ` Avi Kivity
  2010-01-20 14:58       ` Michael S. Tsirkin
  2010-01-20 17:19       ` Davide Libenzi
  0 siblings, 2 replies; 8+ messages in thread
From: Avi Kivity @ 2010-01-20 14:10 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: mtosatti, Davide Libenzi, kvm, Linux Kernel Mailing List

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?  It's not like they're unknown.

-- 
error compiling committee.c: too many arguments to function


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-20 14:10     ` Avi Kivity
@ 2010-01-20 14:58       ` Michael S. Tsirkin
  2010-01-20 15:09         ` Avi Kivity
  2010-01-20 17:19       ` Davide Libenzi
  1 sibling, 1 reply; 8+ messages in thread
From: Michael S. Tsirkin @ 2010-01-20 14:58 UTC (permalink / raw)
  To: Avi Kivity; +Cc: mtosatti, Davide Libenzi, kvm, Linux Kernel Mailing List

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

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-20 14:58       ` Michael S. Tsirkin
@ 2010-01-20 15:09         ` Avi Kivity
  2010-01-20 15:09           ` Michael S. Tsirkin
  0 siblings, 1 reply; 8+ messages in thread
From: Avi Kivity @ 2010-01-20 15:09 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: mtosatti, Davide Libenzi, kvm, Linux Kernel Mailing List

On 01/20/2010 04:58 PM, Michael S. Tsirkin wrote:
>
>> 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.
>
>    

I'd like confirmation on both of these before I push things to stable.

-- 
error compiling committee.c: too many arguments to function

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-20 15:09         ` Avi Kivity
@ 2010-01-20 15:09           ` Michael S. Tsirkin
  0 siblings, 0 replies; 8+ messages in thread
From: Michael S. Tsirkin @ 2010-01-20 15:09 UTC (permalink / raw)
  To: Avi Kivity; +Cc: mtosatti, Davide Libenzi, kvm, Linux Kernel Mailing List

On Wed, Jan 20, 2010 at 05:09:32PM +0200, Avi Kivity wrote:
> On 01/20/2010 04:58 PM, Michael S. Tsirkin wrote:
>>
>>> 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.
>>
>>    
>
> I'd like confirmation on both of these before I push things to stable.

I have observed the interrupt storm. We end up with interrupt being
disabled. Crash is a theoretical issue.

-- 
MST

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 0/2] kvm: fix spurious interrupt with irqfd
  2010-01-20 14:10     ` Avi Kivity
  2010-01-20 14:58       ` Michael S. Tsirkin
@ 2010-01-20 17:19       ` Davide Libenzi
  1 sibling, 0 replies; 8+ messages in thread
From: Davide Libenzi @ 2010-01-20 17:19 UTC (permalink / raw)
  To: Avi Kivity; +Cc: Michael S. Tsirkin, mtosatti, kvm, Linux Kernel Mailing List

On Wed, 20 Jan 2010, Avi Kivity wrote:

> 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?  It's not like they're unknown.

Better material for .33 instead of stable, I agree.


- Davide

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2010-01-20 17:19 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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
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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