Re: [PATCH v5 05/10] x86emul: support MOVDIR64B insn

[Jan Beulich <jbeulich@xxxxxxxx>]

On 03.04.2020 17:13, Andrew Cooper wrote:
> On 03/04/2020 08:57, Jan Beulich wrote:
>> On 03.04.2020 01:12, Andrew Cooper wrote:
>>> On 24/03/2020 12:34, Jan Beulich wrote:
>>>> Introduce a new blk() hook, paralleling the rmw() on in certain way, but
>>>> being intended for larger data sizes, and hence its HVM intermediate
>>>> handling function doesn't fall back to splitting the operation if the
>>>> requested virtual address can't be mapped.
>>>>
>>>> Note that SDM revision 071 doesn't specify exception behavior for
>>>> ModRM.mod == 0b11; assuming #UD here.
>>>>
>>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>> Thanks much, but I'm puzzled by you providing this, and hence
>> would like to double check: You specifically asked that I take
>> care of the cachability issue for MOVDIRI before you would ack
>> that change. How come you're not similarly concerned here?
> 
> This executes the MOVDIR64B instruction directly, so those properties
> are taken care of.  (I think?)
> 
> The MOVDIRI support just does a memcpy().

Oh, now I understand. I could make MOVDIRI follow suit and actually
use this insn to back emulation.

Jan