From c191a7a0f4d3b17cc6cee1d3f721dfe23fc7d6c6 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 13 Sep 2011 10:45:49 +0300 Subject: [PATCH] KVM: x86 emulator: streamline decode of segment registers The opcodes push %seg pop %seg l%seg, %mem, %reg (e.g. lds/les/lss/lfs/lgs) all have an segment register encoded in the instruction. To allow reuse, decode the segment number into src2 during the decode stage instead of the execution stage. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/emulate.c | 99 ++++++++++++++++++++++++------------------ 1 file changed, 57 insertions(+), 42 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 1c95935fe1b7..ab48611b79cf 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -51,6 +51,12 @@ #define OpImmFAddr 17ull /* Immediate far address */ #define OpMemFAddr 18ull /* Far address in memory */ #define OpImmU16 19ull /* Immediate operand, 16 bits, zero extended */ +#define OpES 20ull /* ES */ +#define OpCS 21ull /* CS */ +#define OpSS 22ull /* SS */ +#define OpDS 23ull /* DS */ +#define OpFS 24ull /* FS */ +#define OpGS 25ull /* GS */ #define OpBits 5 /* Width of operand field */ #define OpMask ((1ull << OpBits) - 1) @@ -126,6 +132,12 @@ #define Src2ImmByte (OpImmByte << Src2Shift) #define Src2One (OpOne << Src2Shift) #define Src2Imm (OpImm << Src2Shift) +#define Src2ES (OpES << Src2Shift) +#define Src2CS (OpCS << Src2Shift) +#define Src2SS (OpSS << Src2Shift) +#define Src2DS (OpDS << Src2Shift) +#define Src2FS (OpFS << Src2Shift) +#define Src2GS (OpGS << Src2Shift) #define Src2Mask (OpMask << Src2Shift) #define X2(x...) x, x @@ -3101,16 +3113,19 @@ static struct gprefix pfx_0f_6f_0f_7f = { static struct opcode opcode_table[256] = { /* 0x00 - 0x07 */ I6ALU(Lock, em_add), - D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64), + D(ImplicitOps | Stack | No64 | Src2ES), + D(ImplicitOps | Stack | No64 | Src2ES), /* 0x08 - 0x0F */ I6ALU(Lock, em_or), - D(ImplicitOps | Stack | No64), N, + D(ImplicitOps | Stack | No64 | Src2CS), N, /* 0x10 - 0x17 */ I6ALU(Lock, em_adc), - D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64), + D(ImplicitOps | Stack | No64 | Src2SS), + D(ImplicitOps | Stack | No64 | Src2SS), /* 0x18 - 0x1F */ I6ALU(Lock, em_sbb), - D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64), + D(ImplicitOps | Stack | No64 | Src2DS), + D(ImplicitOps | Stack | No64 | Src2DS), /* 0x20 - 0x27 */ I6ALU(Lock, em_and), N, N, /* 0x28 - 0x2F */ @@ -3178,7 +3193,8 @@ static struct opcode opcode_table[256] = { D2bv(DstMem | SrcImmByte | ModRM), I(ImplicitOps | Stack | SrcImmU16, em_ret_near_imm), I(ImplicitOps | Stack, em_ret), - D(DstReg | SrcMemFAddr | ModRM | No64), D(DstReg | SrcMemFAddr | ModRM | No64), + D(DstReg | SrcMemFAddr | ModRM | No64 | Src2ES), + D(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS), G(ByteOp, group11), G(0, group11), /* 0xC8 - 0xCF */ N, N, N, I(ImplicitOps | Stack, em_ret_far), @@ -3253,20 +3269,22 @@ static struct opcode twobyte_table[256] = { /* 0x90 - 0x9F */ X16(D(ByteOp | DstMem | SrcNone | ModRM| Mov)), /* 0xA0 - 0xA7 */ - D(ImplicitOps | Stack), D(ImplicitOps | Stack), + D(Stack | Src2FS), D(Stack | Src2FS), DI(ImplicitOps, cpuid), D(DstMem | SrcReg | ModRM | BitOp), D(DstMem | SrcReg | Src2ImmByte | ModRM), D(DstMem | SrcReg | Src2CL | ModRM), N, N, /* 0xA8 - 0xAF */ - D(ImplicitOps | Stack), D(ImplicitOps | Stack), + D(Stack | Src2GS), D(Stack | Src2GS), DI(ImplicitOps, rsm), D(DstMem | SrcReg | ModRM | BitOp | Lock), D(DstMem | SrcReg | Src2ImmByte | ModRM), D(DstMem | SrcReg | Src2CL | ModRM), D(ModRM), I(DstReg | SrcMem | ModRM, em_imul), /* 0xB0 - 0xB7 */ D2bv(DstMem | SrcReg | ModRM | Lock), - D(DstReg | SrcMemFAddr | ModRM), D(DstMem | SrcReg | ModRM | BitOp | Lock), - D(DstReg | SrcMemFAddr | ModRM), D(DstReg | SrcMemFAddr | ModRM), + D(DstReg | SrcMemFAddr | ModRM | Src2SS), + D(DstMem | SrcReg | ModRM | BitOp | Lock), + D(DstReg | SrcMemFAddr | ModRM | Src2FS), + D(DstReg | SrcMemFAddr | ModRM | Src2GS), D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov), /* 0xB8 - 0xBF */ N, N, @@ -3436,6 +3454,24 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op, case OpMemFAddr: ctxt->memop.bytes = ctxt->op_bytes + 2; goto mem_common; + case OpES: + op->val = VCPU_SREG_ES; + break; + case OpCS: + op->val = VCPU_SREG_CS; + break; + case OpSS: + op->val = VCPU_SREG_SS; + break; + case OpDS: + op->val = VCPU_SREG_DS; + break; + case OpFS: + op->val = VCPU_SREG_FS; + break; + case OpGS: + op->val = VCPU_SREG_GS; + break; case OpImplicit: /* Special instructions do their own operand decoding. */ default: @@ -3803,26 +3839,15 @@ special_insn: switch (ctxt->b) { case 0x06: /* push es */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_ES); - break; - case 0x07: /* pop es */ - rc = emulate_pop_sreg(ctxt, VCPU_SREG_ES); - break; case 0x0e: /* push cs */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_CS); - break; case 0x16: /* push ss */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_SS); - break; - case 0x17: /* pop ss */ - rc = emulate_pop_sreg(ctxt, VCPU_SREG_SS); - break; case 0x1e: /* push ds */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_DS); + rc = emulate_push_sreg(ctxt, ctxt->src2.val); break; + case 0x07: /* pop es */ + case 0x17: /* pop ss */ case 0x1f: /* pop ds */ - rc = emulate_pop_sreg(ctxt, VCPU_SREG_DS); - break; + rc = emulate_pop_sreg(ctxt, ctxt->src2.val); case 0x40 ... 0x47: /* inc r16/r32 */ emulate_1op(ctxt, "inc"); break; @@ -3869,10 +3894,8 @@ special_insn: rc = em_grp2(ctxt); break; case 0xc4: /* les */ - rc = emulate_load_segment(ctxt, VCPU_SREG_ES); - break; case 0xc5: /* lds */ - rc = emulate_load_segment(ctxt, VCPU_SREG_DS); + rc = emulate_load_segment(ctxt, ctxt->src2.val); break; case 0xcc: /* int3 */ rc = emulate_int(ctxt, 3); @@ -4078,10 +4101,12 @@ twobyte_insn: ctxt->dst.val = test_cc(ctxt->b, ctxt->eflags); break; case 0xa0: /* push fs */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_FS); + case 0xa8: /* push gs */ + rc = emulate_push_sreg(ctxt, ctxt->src2.val); break; case 0xa1: /* pop fs */ - rc = emulate_pop_sreg(ctxt, VCPU_SREG_FS); + case 0xa9: /* pop gs */ + rc = emulate_pop_sreg(ctxt, ctxt->src2.val); break; case 0xa3: bt: /* bt */ @@ -4094,12 +4119,6 @@ twobyte_insn: case 0xa5: /* shld cl, r, r/m */ emulate_2op_cl(ctxt, "shld"); break; - case 0xa8: /* push gs */ - rc = emulate_push_sreg(ctxt, VCPU_SREG_GS); - break; - case 0xa9: /* pop gs */ - rc = emulate_pop_sreg(ctxt, VCPU_SREG_GS); - break; case 0xab: bts: /* bts */ emulate_2op_SrcV_nobyte(ctxt, "bts"); @@ -4128,18 +4147,14 @@ twobyte_insn: } break; case 0xb2: /* lss */ - rc = emulate_load_segment(ctxt, VCPU_SREG_SS); + case 0xb4: /* lfs */ + case 0xb5: /* lgs */ + rc = emulate_load_segment(ctxt, ctxt->src2.val); break; case 0xb3: btr: /* btr */ emulate_2op_SrcV_nobyte(ctxt, "btr"); break; - case 0xb4: /* lfs */ - rc = emulate_load_segment(ctxt, VCPU_SREG_FS); - break; - case 0xb5: /* lgs */ - rc = emulate_load_segment(ctxt, VCPU_SREG_GS); - break; case 0xb6 ... 0xb7: /* movzx */ ctxt->dst.bytes = ctxt->op_bytes; ctxt->dst.val = (ctxt->d & ByteOp) ? (u8) ctxt->src.val -- 2.39.5