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Subject[PATCH 06/42] KVM: x86 emulator: Introduce No64 decode option
Date
From: Mohammed Gamal <m.gamal005@gmail.com>

Introduces a new decode option "No64", which is used for instructions that are
invalid in long mode.

Signed-off-by: Mohammed Gamal <m.gamal005@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/emulate.c | 42 ++++++++++++++----------------------------
1 files changed, 14 insertions(+), 28 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 1cdfec5..1f0ff4a 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -75,6 +75,8 @@
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
#define GroupMask 0xff /* Group number stored in bits 0:7 */
+/* Misc flags */
+#define No64 (1<<28)
/* Source 2 operand type */
#define Src2None (0<<29)
#define Src2CL (1<<29)
@@ -93,21 +95,21 @@ static u32 opcode_table[256] = {
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
- ImplicitOps | Stack, ImplicitOps | Stack,
+ ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
/* 0x08 - 0x0F */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
- 0, 0, ImplicitOps | Stack, 0,
+ 0, 0, ImplicitOps | Stack | No64, 0,
/* 0x10 - 0x17 */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
- ImplicitOps | Stack, ImplicitOps | Stack,
+ ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
/* 0x18 - 0x1F */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,
- ImplicitOps | Stack, ImplicitOps | Stack,
+ ImplicitOps | Stack | No64, ImplicitOps | Stack | No64,
/* 0x20 - 0x27 */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
@@ -161,7 +163,7 @@ static u32 opcode_table[256] = {
/* 0x90 - 0x97 */
DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg, DstReg,
/* 0x98 - 0x9F */
- 0, 0, SrcImm | Src2Imm16, 0,
+ 0, 0, SrcImm | Src2Imm16 | No64, 0,
ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
/* 0xA0 - 0xA7 */
ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
@@ -188,7 +190,7 @@ static u32 opcode_table[256] = {
ByteOp | DstMem | SrcImm | ModRM | Mov, DstMem | SrcImm | ModRM | Mov,
/* 0xC8 - 0xCF */
0, 0, 0, ImplicitOps | Stack,
- ImplicitOps, SrcImmByte, ImplicitOps, ImplicitOps,
+ ImplicitOps, SrcImmByte, ImplicitOps | No64, ImplicitOps,
/* 0xD0 - 0xD7 */
ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
ByteOp | DstMem | SrcImplicit | ModRM, DstMem | SrcImplicit | ModRM,
@@ -201,7 +203,7 @@ static u32 opcode_table[256] = {
ByteOp | SrcImmUByte, SrcImmUByte,
/* 0xE8 - 0xEF */
SrcImm | Stack, SrcImm | ImplicitOps,
- SrcImmU | Src2Imm16, SrcImmByte | ImplicitOps,
+ SrcImmU | Src2Imm16 | No64, SrcImmByte | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
/* 0xF0 - 0xF7 */
@@ -967,6 +969,11 @@ done_prefixes:
}
}

+ if (mode == X86EMUL_MODE_PROT64 && (c->d & No64)) {
+ kvm_report_emulation_failure(ctxt->vcpu, "invalid x86/64 instruction");;
+ return -1;
+ }
+
if (c->d & Group) {
group = c->d & GroupMask;
c->modrm = insn_fetch(u8, 1, c->eip);
@@ -1739,15 +1746,9 @@ special_insn:
emulate_2op_SrcV("add", c->src, c->dst, ctxt->eflags);
break;
case 0x06: /* push es */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
emulate_push_sreg(ctxt, VCPU_SREG_ES);
break;
case 0x07: /* pop es */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_ES);
if (rc != 0)
goto done;
@@ -1757,9 +1758,6 @@ special_insn:
emulate_2op_SrcV("or", c->src, c->dst, ctxt->eflags);
break;
case 0x0e: /* push cs */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
emulate_push_sreg(ctxt, VCPU_SREG_CS);
break;
case 0x10 ... 0x15:
@@ -1767,15 +1765,9 @@ special_insn:
emulate_2op_SrcV("adc", c->src, c->dst, ctxt->eflags);
break;
case 0x16: /* push ss */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
emulate_push_sreg(ctxt, VCPU_SREG_SS);
break;
case 0x17: /* pop ss */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_SS);
if (rc != 0)
goto done;
@@ -1785,15 +1777,9 @@ special_insn:
emulate_2op_SrcV("sbb", c->src, c->dst, ctxt->eflags);
break;
case 0x1e: /* push ds */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
emulate_push_sreg(ctxt, VCPU_SREG_DS);
break;
case 0x1f: /* pop ds */
- if (ctxt->mode == X86EMUL_MODE_PROT64)
- goto cannot_emulate;
-
rc = emulate_pop_sreg(ctxt, ops, VCPU_SREG_DS);
if (rc != 0)
goto done;
--
1.6.5.2


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