On Fri, Aug 04, 2023 at 07:58:21AM +0200, Jan Beulich wrote:
> In an entirely different context I came across Linux commit 428e3d08574b
> ("KVM: x86: Fix zero iterations REP-string"), which points out that
> we're still doing things wrong: For one, there's no zero-extension at
> all on AMD. And then while RCX is zero-extended from 32 bits uniformly
> for all string instructions on newer hardware, RSI/RDI are only for MOVS
> and STOS on the systems I have access to. (On an old family 0xf system
> I've further found that for REP LODS even RCX is not zero-extended.)
>
> Fixes: 79e996a89f69 ("x86emul: correct 64-bit mode repeated string insn
> handling with zero count")
> Signed-off-by: Jan Beulich <[email protected]>
Acked-by: Roger Pau Monné <[email protected]>
> ---
> Partly RFC for none of this being documented anywhere (and it partly
> being model specific); inquiry pending.
Did you get any reply on this?
Thanks, Roger.
