Re: [PATCH] Intel/vpmu: Use Intel VPMU quirk on all family 6 processors

[George Dunlap <george.dunlap@eu.citrix.com>]

On 05/30/2013 05:33 PM, Boris Ostrovsky wrote:
> On 05/16/2013 08:30 AM, Jan Beulich wrote:
>>>>> On 10.05.13 at 11:46, George Dunlap <George.Dunlap@eu.citrix.com>
>>>>> wrote:
>>> On Thu, May 9, 2013 at 9:45 PM, Boris Ostrovsky
>>> <boris.ostrovsky@oracle.com> wrote:
>>>> On 05/09/2013 04:34 PM, Boris Ostrovsky wrote:
>>>>> Currently only a few Intel models have VPMU workaround turned on. It
>>>>> appears, however, that this issue exists on more models than what is
>>>>> covered by check_pmc_quirk(). Since we don't know exactly which cpus
>>>>> are affected we should turn this workaround on for all family 6
>>>>> processors.
>>>>
>>>> Haitao,
>>>>
>>>> A few weeks ago we had an email thread about this issue
>>>> (http://lists.xen.org/archives/html/xen-devel/2013-03/msg02618.html)
>>>> Did you have a chance to clarify with your HW folks what this is?
>>>>
>>>> We kept hitting this on various models which is why I am suggesting
>>>> this
>>>> patch (and I think it should be considered for 4.3).
>>> In principle it's a bug fix, and fine for 4.3.  But it would be good
>>> to get some feedback from someone at Intel.
>> Intel, anyone???
>>
>> Thanks, Jan
>>
>
> I haven't seen any responses from Intel folks about this issue.
>
> Do we wait for post-4.3?

Our goals at this point:
- Bug-free release
- Awesome release
- On-time release

I take it that the main risk here is that vcpu for some models which 
would have otherwise worked will not work anymore?

But at his point you *know* many models which don't work without it; so 
on the whole I'm inclined to say that it's an "accept" on the 
cost/benefits analysis.

  -George