Sheng Yang wrote:
> From 9cd9d5cde7341d5e9de41b1070cea7a98e7d8cc9 Mon Sep 17 00:00:00 2001
> From: Sheng Yang <[EMAIL PROTECTED]>
> Date: Thu, 15 Nov 2007 15:11:58 +0800
> Subject: [PATCH 2/2] KVM: x86 emulator: Discard CR2 in x86 emulator
>
> For CR2 is unreliable and unavailable in many condition, this patch
> completely decode memory operand instead of using CR2 in x86 emulator.
>
>
>
One of my innermost wishes...
> diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
> index aa6c3d8..85a0776 100644
> --- a/drivers/kvm/x86.c
> +++ b/drivers/kvm/x86.c
> @@ -1293,7 +1293,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
>
> vcpu->emulate_ctxt.vcpu = vcpu;
> vcpu->emulate_ctxt.eflags = kvm_x86_ops->get_rflags(vcpu);
> - vcpu->emulate_ctxt.cr2 = cr2;
> + vcpu->emulate_ctxt.memop = 0;
>
We have c->modrm_ea which can be used for the memory operand.
> diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
> index c020010..95536a8 100644
> --- a/drivers/kvm/x86_emulate.c
> +++ b/drivers/kvm/x86_emulate.c
> @@ -880,6 +880,8 @@ done_prefixes:
> break;
> }
> c->src.type = OP_MEM;
> + ctxt->memop = insn_fetch(u32, c->src.bytes, c->eip);
> + c->eip -= c->src.bytes; /* keep the page fault ip */
>
I don't understand this. In the cases where the memory operand address
is encoded in the instruction, we fetch it explicity. When it isn't,
this is broken.
> break;
> case SrcImm:
> c->src.type = OP_IMM;
> @@ -918,14 +920,18 @@ done_prefixes:
> c->twobyte && (c->b == 0xb6 || c->b == 0xb7));
> break;
> case DstMem:
> + c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
>
This seems unrelated; needs a separate patch. Please check that movzx
and movsx aren't affected by this.
> /*
> * For instructions with a ModR/M byte, switch to register
> * access if Mod = 3.
> */
> - if ((c->d & ModRM) && c->modrm_mod == 3)
> + if ((c->d & ModRM) && c->modrm_mod == 3) {
> c->dst.type = OP_REG;
> - else
> - c->dst.type = OP_MEM;
> + break;
> + }
> + c->dst.type = OP_MEM;
> + ctxt->memop = insn_fetch(u32, c->dst.bytes, c->eip);
> + c->eip -= c->dst.bytes; /* keep the page fault ip */
>
Ditto.
--
error compiling committee.c: too many arguments to function
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