[PATCH 1/2] KVM: x86 emulator: Add decoding of 16bit second in memory argument

[PATCH 1/2] KVM: x86 emulator: Add decoding of 16bit second in memory argument

[Gleb Natapov]

Add decoding of Ep type of argument used by callf/jmpf.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/kvm/emulate.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c9f604b..d288107 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -85,6 +85,7 @@
 #define Src2ImmByte (2<<29)
 #define Src2One     (3<<29)
 #define Src2Imm16   (4<<29)
+#define Src2Mem16   (5<<29)
 #define Src2Mask    (7<<29)
 
 enum {
@@ -1163,6 +1164,10 @@ done_prefixes:
 		c->src2.bytes = 1;
 		c->src2.val = 1;
 		break;
+	case Src2Mem16:
+		c->src2.bytes = 2;
+		c->src2.type = OP_MEM;
+		break;
 	}
 
 	/* Decode and fetch the destination operand: register or memory. */
@@ -1881,6 +1886,17 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		c->src.orig_val = c->src.val;
 	}
 
+	if (c->src2.type == OP_MEM) {
+		c->src2.ptr = (unsigned long *)(memop + c->src.bytes);
+		c->src2.val = 0;
+		rc = ops->read_emulated((unsigned long)c->src2.ptr,
+					&c->src2.val,
+					c->src2.bytes,
+					ctxt->vcpu);
+		if (rc != X86EMUL_CONTINUE)
+			goto done;
+	}
+
 	if ((c->d & DstMask) == ImplicitOps)
 		goto special_insn;
 
-- 
1.6.5

Re: [PATCH 1/2] KVM: x86 emulator: Add decoding of 16bit second in memory argument

[Avi Kivity]

On 02/24/2010 12:28 PM, Gleb Natapov wrote:
> Add decoding of Ep type of argument used by callf/jmpf.
>
> Signed-off-by: Gleb Natapov<gleb@redhat.com>
> ---
>   arch/x86/kvm/emulate.c |   16 ++++++++++++++++
>   1 files changed, 16 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index c9f604b..d288107 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -85,6 +85,7 @@
>   #define Src2ImmByte (2<<29)
>   #define Src2One     (3<<29)
>   #define Src2Imm16   (4<<29)
> +#define Src2Mem16   (5<<29)
>   #define Src2Mask    (7<<29)
>
>   enum {
> @@ -1163,6 +1164,10 @@ done_prefixes:
>   		c->src2.bytes = 1;
>   		c->src2.val = 1;
>   		break;
> +	case Src2Mem16:
> +		c->src2.bytes = 2;
> +		c->src2.type = OP_MEM;
> +		break;
>   	}
>
>   	/* Decode and fetch the destination operand: register or memory. */
> @@ -1881,6 +1886,17 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
>   		c->src.orig_val = c->src.val;
>   	}
>
> +	if (c->src2.type == OP_MEM) {
> +		c->src2.ptr = (unsigned long *)(memop + c->src.bytes);
> +		c->src2.val = 0;
> +		rc = ops->read_emulated((unsigned long)c->src2.ptr,
> +					&c->src2.val,
> +					c->src2.bytes,
> +					ctxt->vcpu);
> +		if (rc != X86EMUL_CONTINUE)
> +			goto done;
> +	}
> +
>    

This introduces a dependency between src and src2.  The alternative is 
to have an offset+segment operand type, but that introduces all types of 
complications, so I guess the dependency is worth it.  But at least 
document it when you define Src2Mem16.

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

[PATCH 1/2] KVM: x86 emulator: Add decoding of 16bit second in memory argument

[Gleb Natapov]

Add decoding of Ep type of argument used by callf/jmpf.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/kvm/emulate.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c9f604b..97a7403 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -85,6 +85,9 @@
 #define Src2ImmByte (2<<29)
 #define Src2One     (3<<29)
 #define Src2Imm16   (4<<29)
+#define Src2Mem16   (5<<29) /* Used for Ep encoding. First argument has to be
+			       in memory and second argument is located
+			       immediately after the first one in memory. */
 #define Src2Mask    (7<<29)
 
 enum {
@@ -1163,6 +1166,10 @@ done_prefixes:
 		c->src2.bytes = 1;
 		c->src2.val = 1;
 		break;
+	case Src2Mem16:
+		c->src2.bytes = 2;
+		c->src2.type = OP_MEM;
+		break;
 	}
 
 	/* Decode and fetch the destination operand: register or memory. */
@@ -1881,6 +1888,17 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		c->src.orig_val = c->src.val;
 	}
 
+	if (c->src2.type == OP_MEM) {
+		c->src2.ptr = (unsigned long *)(memop + c->src.bytes);
+		c->src2.val = 0;
+		rc = ops->read_emulated((unsigned long)c->src2.ptr,
+					&c->src2.val,
+					c->src2.bytes,
+					ctxt->vcpu);
+		if (rc != X86EMUL_CONTINUE)
+			goto done;
+	}
+
 	if ((c->d & DstMask) == ImplicitOps)
 		goto special_insn;
 
-- 
1.6.5

[PATCH 2/2] KVM: x86 emulator: Implement jmp far opcode ff/5

[Gleb Natapov]

Implement jmp far opcode ff/5. It is used by multiboot loader.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
---
 arch/x86/kvm/emulate.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 97a7403..5b6794a 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -346,7 +346,8 @@ static u32 group_table[] = {
 	[Group5*8] =
 	DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM,
 	SrcMem | ModRM | Stack, 0,
-	SrcMem | ModRM | Stack, 0, SrcMem | ModRM | Stack, 0,
+	SrcMem | ModRM | Stack, SrcMem | ModRM | Src2Mem16 | ImplicitOps,
+	SrcMem | ModRM | Stack, 0,
 	[Group7*8] =
 	0, 0, ModRM | SrcMem | Priv, ModRM | SrcMem | Priv,
 	SrcNone | ModRM | DstMem | Mov, 0,
@@ -2322,6 +2323,7 @@ special_insn:
 	case 0xe9: /* jmp rel */
 		goto jmp;
 	case 0xea: /* jmp far */
+	jump_far:
 		if (kvm_load_segment_descriptor(ctxt->vcpu, c->src2.val,
 						VCPU_SREG_CS))
 			goto done;
@@ -2397,11 +2399,16 @@ special_insn:
 		ctxt->eflags |= EFLG_DF;
 		c->dst.type = OP_NONE;	/* Disable writeback. */
 		break;
-	case 0xfe ... 0xff:	/* Grp4/Grp5 */
+	case 0xfe: /* Grp4 */
+	grp45:
 		rc = emulate_grp45(ctxt, ops);
 		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		break;
+	case 0xff: /* Grp5 */
+		if (c->modrm_reg == 5)
+			goto jump_far;
+		goto grp45;
 	}
 
 writeback:
-- 
1.6.5

Re: [PATCH 1/2] KVM: x86 emulator: Add decoding of 16bit second in memory argument

[Avi Kivity]

On 02/25/2010 04:36 PM, Gleb Natapov wrote:
> Add decoding of Ep type of argument used by callf/jmpf.
>
>    

Applied both, thanks.

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