Re: [PATCH 1/2]KVM: x86_emulator: Decode the memory operand for 'mov'

Avi Kivity
2007-10-26T09:02:38Z

Yang, Sheng wrote:
> >From ebfc23b71051e5ab19d22fb3f9c3d57721566ea9 Mon Sep 17 00:00:00 2001
> From: Sheng Yang <sheng.yang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Date: Fri, 26 Oct 2007 13:41:28 +0800
> Subject: [PATCH] KVM: x86_emulator: Decode the memory operand for 'mov'
>
> For the following TPR patch, we must get gva for executing instructions.
> Most
> memory operands are decoded in ModR/M part, except some kinds of 'mov'.
> This
> patch decoded the memory operand for these 'mov' instructions, instead
> of using
> CR2.
>
> Signed-off-by: Sheng Yang <sheng.yang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> ---
> drivers/kvm/x86_emulate.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
> index f858c01..f75f75a 100644
> --- a/drivers/kvm/x86_emulate.c
> +++ b/drivers/kvm/x86_emulate.c
> @@ -837,6 +837,11 @@ modrm_done:
> && c->modrm_reg == 7)
> break;
> srcmem_common:
> + /* Decode memory operand for mov(0xa0 ... 0xa1)*/
> + if ((c->b == 0xa0) || (c->b == 0xa1)) {
> + ctxt->cr2 = insn_fetch(u32, c->src.bytes,
> c->eip);
> + c->eip -= c->src.bytes;
> + }
>

We're moving eip backwards here, then forwards in x86_emulate_insn()...
I'm getting dizzy.

How about add a MemAbs bitflag in decode it outside, similar to the
ModRM flag and decoding?

--
error compiling committee.c: too many arguments to function