Re: [KVM PATCH v9 0/5] irqfd fixes and enhancements

From: Gregory Haskins <ghaskins@novell.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	davidel@xmailserver.org
Subject: Re: [KVM PATCH v9 0/5] irqfd fixes and enhancements
Date: Mon, 06 Jul 2009 14:48:33 -0400	[thread overview]
Message-ID: <4A524701.3020808@novell.com> (raw)
In-Reply-To: <20090706164955.GE12399@redhat.com>

[-- Attachment #1: Type: text/plain, Size: 1262 bytes --]

Michael S. Tsirkin wrote:
> On Mon, Jul 06, 2009 at 12:41:59PM -0400, Gregory Haskins wrote:
>   
>> Michael S. Tsirkin wrote:
>>     
>>>>    
>>>>         
>>> wouldn't it be cleaner to error out in the for each loop if we don't
>>> find an entry to deactivate?  Might be helpful for apps to get an error
>>> if they didn't deassign anything.
>>>   
>>>       
>> Again, irqfds.init is somewhat orthogonal to whether the list is
>> populated or not.  This check is for sanity (how can you deassign if you
>> didnt assign, etc).  Normally this would be a simple BUG_ON() sanity
>> check, but I don't want a malicious/broken userspace to gain an easy
>> attack vector ;)
>>     
>
> what I'm saying is that deassign should return an error if it's passed
> and entry that is not on the list.

This isn't an unreasonable request, and I believe this is actually the
way the original deassign logic worked before we yanked the feature a
few weeks ago.  Its only slightly complicated by the fact that we may
match multiple irqfds, but I think we solved that before by returning
the number we matched.

If Avi answers the other mail stating he wants to still see the
on-demand work go in, lets use your suggestion.

Regards,
-Greg

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 266 bytes --]