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SubjectRe: [RFC PATCH] x86/insn: support decode MOVSXD instruction for MMIO
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On 3/28/23 21:59, Wu Zongyong wrote:
> It seems MOVSXD which opcode is 0x63 is not handled, support
> to decode it in insn_decode_mmio().

Aren't there some caveats to worry about with this instruction based on
the presence of the REX prefix 64-bit operand size bit? Sometimes it can
be a sign extended and sometimes it can be a zero extended.

Thanks,
Tom

>
> Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
> ---
> arch/x86/lib/insn-eval.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
> index 558a605929db..db6f93bad219 100644
> --- a/arch/x86/lib/insn-eval.c
> +++ b/arch/x86/lib/insn-eval.c
> @@ -1607,6 +1607,10 @@ enum insn_mmio_type insn_decode_mmio(struct insn *insn, int *bytes)
> return INSN_MMIO_DECODE_FAILED;
>
> switch (insn->opcode.bytes[0]) {
> + case 0x63: /* MOVSXD r64, m32 */
> + *bytes = 4;
> + type = INSN_MMIO_READ_SIGN_EXTEND;
> + break;
> case 0x88: /* MOV m8,r8 */
> *bytes = 1;
> fallthrough;

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