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Re: [Xen-devel] Ping: [PATCH] x86/HVM: use single (atomic) MOV for aligned emulated writes



On Fri, Dec 27, 2019 at 11:09 AM Andrew Cooper
<andrew.cooper3@xxxxxxxxxx> wrote:
>
> On 20/12/2019 16:23, Jan Beulich wrote:
> > On 16.09.2019 11:40, Jan Beulich wrote:
> >> Using memcpy() may result in multiple individual byte accesses
> >> (dependening how memcpy() is implemented and how the resulting insns,
> >> e.g. REP MOVSB, get carried out in hardware), which isn't what we
> >> want/need for carrying out guest insns as correctly as possible. Fall
> >> back to memcpy() only for accesses not 2, 4, or 8 bytes in size.
> >>
> >> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> >> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Should xen/arch/x86/mm/shadow/hvm.c:hvm_emulate_write() be similarly changed?

Thanks,
Jason

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