Messages in this thread | | | Date | Wed, 29 Mar 2023 08:49:24 -0500 | Subject | Re: [RFC PATCH] x86/insn: support decode MOVSXD instruction for MMIO | From | Tom Lendacky <> |
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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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