Re: [PATCH v3 3/4] xen/hvm: introduce a fpu_uninitialised field to the CPU save record

["Jan Beulich" <JBeulich@suse.com>]

>>> On 24.11.15 at 15:38, <roger.pau@citrix.com> wrote:
> El 24/11/15 a les 14.34, Jan Beulich ha escrit:
>>>>> On 24.11.15 at 14:10, <roger.pau@citrix.com> wrote:
>>> El 20/11/15 a les 16.49, Jan Beulich ha escrit:
>>>>>>> On 18.11.15 at 17:37, <roger.pau@citrix.com> wrote:
>>>>> @@ -157,6 +159,8 @@ struct hvm_hw_cpu {
>>>>>      };
>>>>>      /* error code for pending event */
>>>>>      uint32_t error_code;
>>>>> +    /* is fpu initialised? */
>>>>> +    uint32_t fpu_initialised;
>>>>
>>>> A whole uint32_t for just one bit? Didn't we talk about making this
>>>> new field a flags one, consuming just one bit from it?
>>>
>>> AFAIK we agreed on adding this field to the tail and making it a
>>> uint32_t so that when new fields are added they can be detected by
>>> looking at the size of the structure:
>>>
>>> http://marc.info/?l=xen-devel&m=144490321208291 
>> 
>> Admittedly it's a little implicit, but that mail has, in its quoting parts,
>> 
>> "... (and validate unused tail bits are zero, so they can be used for
>> something later on)"
>> 
>> going back to that intention of using just a single bit here afaict.
> 
> Ack. I have to admit I've misunderstood that part. Then I guess the
> field should also have a more generic name, like "flags", and
> fpu_initialised should be defined as (1U << 0).

Yes.

Jan