Re: [Xen-devel] [PATCH] xen: arm: arm64: Adding VFP save/restore support.

[Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>]

Hi Ian/ Julien,

On 7 February 2014 11:01, Pranavkumar Sawargaonkar
<pranavkumar@xxxxxxxxxx> wrote:
> Hi Ian,
>
> On 6 February 2014 18:41, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
>> On Thu, 2014-02-06 at 13:08 +0000, Julien Grall wrote:
>>>
>>> On 06/02/14 12:57, Ian Campbell wrote:
>>> > On Thu, 2014-02-06 at 12:44 +0000, Julien Grall wrote:
>>> >>> +                 :: "r" ((char *)(&v->arch.vfp.fpregs)): "memory");
>>> >>
>>> >> I remember we had a discussion when I have implemented vfp context
>>> >> switch for arm32 for the memory constraints
>>> >> (http://lists.xen.org/archives/html/xen-devel/2013-06/msg00110.html).
>>> >>
>>> >> I think you should use "=Q" also here to avoid cloberring the whole 
>>> >> memory.
>>> >
>>> > Yes, I forgot to say: I think getting something in now is the priority,
>>> > which is why I committed it, but this should be tightened up, probably
>>> > for 4.5 unless the difference is benchmarkable.
>>>
>>> The fix is very simple (a matter of 2 lines changes). I would prefer to
>>> delay this patch for a couple of days and having a correct
>>> implementation from the beginning, so we will not forgot to change the
>>> code for Xen 4.5.
>>
>> And I would rather close this rather large hole right now and not wait
>> for two more days when we are looking at doing what might be the final
>> rc soon.
>>
>> I had already applied before you said anything, so the point is moot.
>>
>> Anyway, if someone wants to submit for 4.4 with a case for a release
>> exception then I'm sure George will consider it.
>>
>> Otherwise this thread is now in my QUEUE-4.5 folder so I'll get a
>> reminder shortly after the release when I go through that.
>>
>>> Moreover Pranav usually answer quickly :).
>>
>> If he's awake/at work, it's out of office hours for him now.
>
> : ) :) , sorry somehow I missed this yesterday.
>
> If "=Q"  is really critical i can quickly send you a new patch against
> your commit in staging branch
> (http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=712eb2e04da2cbcd9908f74ebd47c6df60d6d12f)

Posted a new patch with the desired fix -
"xen: arm: arm64: Fix memory cloberring issues during VFP save restore."

>>
>> Ian.
>>
> Thanks,
> Pranav
Thanks,
Pranav

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