[PATCH non-atomic-injection] x86 emulator: Add cwd/cdq/cqo instruction (opcode 0x99)

[PATCH non-atomic-injection] x86 emulator: Add cwd/cdq/cqo instruction (opcode 0x99)

[Mohammed Gamal]

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
---
 arch/x86/kvm/emulate.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ee4bb69..fddf76d 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2421,7 +2421,7 @@ static struct opcode opcode_table[256] = {
 	/* 0x90 - 0x97 */
 	X8(D(SrcAcc | DstReg)),
 	/* 0x98 - 0x9F */
-	D(DstAcc | SrcNone), N, D(SrcImmFAddr | No64), N,
+	D(DstAcc | SrcNone), D(ImplicitOps), D(SrcImmFAddr | No64), N,
 	D(ImplicitOps | Stack), D(ImplicitOps | Stack), N, N,
 	/* 0xA0 - 0xA7 */
 	D(ByteOp | DstAcc | SrcMem | Mov | MemAbs), D(DstAcc | SrcMem | Mov | MemAbs),
@@ -3161,6 +3161,20 @@ special_insn:
 		case 8: c->dst.val = (s32)c->dst.val; break;
 		}
 		break;
+	case 0x99: /* cwd/cdq/cqo */ {
+		unsigned long rax = c->regs[VCPU_REGS_RAX];
+		unsigned long sign_bit = 1 << ((c->op_bytes * 8) - 1);
+
+		if (rax & sign_bit) {
+			switch (c->op_bytes) {
+			case 2: c->regs[VCPU_REGS_RDX] = 0xffff; break;
+			case 4: c->regs[VCPU_REGS_RDX] = 0xffffffff; break;
+			case 8: c->regs[VCPU_REGS_RDX] = 0xffffffffffffffff; break;
+			}
+		} else 
+			c->regs[VCPU_REGS_RDX] = 0;
+		}
+		break;
 	case 0x9c: /* pushf */
 		c->src.val =  (unsigned long) ctxt->eflags;
 		emulate_push(ctxt, ops);
-- 
1.7.0.4

Re: [PATCH non-atomic-injection] x86 emulator: Add cwd/cdq/cqo instruction (opcode 0x99)

[Avi Kivity]

  On 08/19/2010 05:25 PM, Mohammed Gamal wrote:
> Signed-off-by: Mohammed Gamal<m.gamal005@gmail.com>
> ---
>   arch/x86/kvm/emulate.c |   16 +++++++++++++++-
>   1 files changed, 15 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index ee4bb69..fddf76d 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -2421,7 +2421,7 @@ static struct opcode opcode_table[256] = {
>   	/* 0x90 - 0x97 */
>   	X8(D(SrcAcc | DstReg)),
>   	/* 0x98 - 0x9F */
> -	D(DstAcc | SrcNone), N, D(SrcImmFAddr | No64), N,
> +	D(DstAcc | SrcNone), D(ImplicitOps), D(SrcImmFAddr | No64), N,
>   	D(ImplicitOps | Stack), D(ImplicitOps | Stack), N, N,
>   	/* 0xA0 - 0xA7 */
>   	D(ByteOp | DstAcc | SrcMem | Mov | MemAbs), D(DstAcc | SrcMem | Mov | MemAbs),
> @@ -3161,6 +3161,20 @@ special_insn:
>   		case 8: c->dst.val = (s32)c->dst.val; break;
>   		}
>   		break;
> +	case 0x99: /* cwd/cdq/cqo */ {
> +		unsigned long rax = c->regs[VCPU_REGS_RAX];
> +		unsigned long sign_bit = 1<<  ((c->op_bytes * 8) - 1);
> +
> +		if (rax&  sign_bit) {
> +			switch (c->op_bytes) {
> +			case 2: c->regs[VCPU_REGS_RDX] = 0xffff; break;
> +			case 4: c->regs[VCPU_REGS_RDX] = 0xffffffff; break;
> +			case 8: c->regs[VCPU_REGS_RDX] = 0xffffffffffffffff; break;
> +			}
> +		} else
> +			c->regs[VCPU_REGS_RDX] = 0;
> +		}
> +		break;

Again I have something (a bit simpler) in my queue, will push it soon.  
I applied your test case.

We need to work out a way of not duplicating this work.

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