Re: [Xen-devel] [PATCH 4/6] x86emul: reduce FPU handling code size

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 07/12/16 15:16, Jan Beulich wrote:
>>>> On 07.12.16 at 16:06, <andrew.cooper3@xxxxxxxxxx> wrote:
>> On 06/12/16 14:13, Jan Beulich wrote:
>>> @@ -3670,6 +3652,7 @@ x86_emulate(
>>>  
>>>      case 0xd8: /* FPU 0xd8 */
>>>          host_and_vcpu_must_have(fpu);
>>> +        get_fpu(X86EMUL_FPU_fpu, &fic);
>>>          switch ( modrm )
>>>          {
>>>          case 0xc0 ... 0xc7: /* fadd %stN,%st */
>>> @@ -3715,10 +3698,12 @@ x86_emulate(
>>>                  break;
>>>              }
>>>          }
>>> +        put_fpu(&fic);
>>>          break;
>> This repositioning does mean that we might skip the put_fpu() call,
>> although we still retain the catch-all _put_fpu().
>>
>> I think this is still safe as we only skip this put_fpu() in cases where
>> we didn't emulate an instruction, and there isn't the risk of missing a
>> pending FPU exception.
> Correct - the catch-all one is sufficient for all cases.

Ok.  Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

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