Re: [Xen-devel] [PATCH] x86emul: don't read mask register on AVX512F-incapable platforms

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 28.03.19 at 19:03, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 28/03/2019 17:44, George Dunlap wrote:
>> On 3/28/19 5:03 PM, Jan Beulich wrote:
>>> Reported-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>> That seems to fix all the ones related to the crashes I was seeing:
>>
>> Tested-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>>
>>> ---
>>> This is surely a stable tree candidate, unless it could still make it
>>> into 4.12 before the release.
>>>
>>> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
>>> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
>>> @@ -3511,7 +3511,7 @@ x86_emulate(
>>>      }
>>>  
>>>      /* With a memory operand, fetch the mask register in use (if any). */
>>> -    if ( ea.type == OP_MEM && evex.opmsk )
>>> +    if ( ea.type == OP_MEM && cpu_has_avx512f && evex.opmsk )
> 
> So, this certainly will fix the crash as reported, you need an %xcr0
> check, to prevent other ways of this stub faulting.

Oh, of course. Let me see how to best fit this in.

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel