x86 emulator: Add 'push/pop sreg' instructions
PATCH 1/1 x86 emulator: Add 'push/pop sreg' instructions
Signed-off-by Mohammed Gamal <[email protected]>
--- arch/x86/kvm/emulate.c | 99 +++++++++++++++++++++++++++++++++++++++++++++--- 1 files changed, 93 insertions(+), 6 deletions(-)
arch/x86/kvm/emulate.c +93 -6
@@ -92,19 +92,22 @@ static u32 opcode_table[256] = {/* 0x00 - 0x07 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, - ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,0 ,0 , + ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, + ImplicitOps | Stack, ImplicitOps | Stack,/* 0x08 - 0x0F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, -0 ,0 ,0 ,0 , +0 ,0 , ImplicitOps | Stack,0 ,/* 0x10 - 0x17 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, - ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,0 ,0 , + ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, + ImplicitOps | Stack, ImplicitOps | Stack,/* 0x18 - 0x1F */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM, - ByteOp | DstAcc | SrcImm, DstAcc | SrcImm,0 ,0 , + ByteOp | DstAcc | SrcImm, DstAcc | SrcImm, + ImplicitOps | Stack, ImplicitOps | Stack,/* 0x20 - 0x27 */ ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, ByteOp | DstReg | SrcMem | ModRM, DstReg | SrcMem | ModRM,
@@ -244,11 +247,13 @@ static u32 twobyte_table[256] = {/* 0x90 - 0x9F */ 0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,0 ,/* 0xA0 - 0xA7 */ -0 ,0 ,0 , DstMem | SrcReg | ModRM | BitOp, + ImplicitOps | Stack, ImplicitOps | Stack, +0 , DstMem | SrcReg | ModRM | BitOp, DstMem | SrcReg | Src2ImmByte | ModRM, DstMem | SrcReg | Src2CL | ModRM,0 ,0 ,/* 0xA8 - 0xAF */ -0 ,0 ,0 , DstMem | SrcReg | ModRM | BitOp, + ImplicitOps | Stack, ImplicitOps | Stack, +0 , DstMem | SrcReg | ModRM | BitOp, DstMem | SrcReg | Src2ImmByte | ModRM, DstMem | SrcReg | Src2CL | ModRM, ModRM, 0,
@@ -1186,6 +1191,45 @@ static int emulate_pop(struct x86_emulate_ctxt *ctxt,return rc; } +static void emulate_push_sreg (struct x86_emulate_ctxt *ctxt,int seg) +{ +struct decode_cache *c = &ctxt->decode; +struct kvm_segment segment; + +if (ctxt->mode ==X86EMUL_MODE_PROT64 && (seg !=VCPU_SREG_FS || + seg !=VCPU_SREG_GS )) { +kvm_queue_exception (ctxt->vcpu,UD_VECTOR ); +return ; + } + + kvm_x86_ops->get_segment (ctxt->vcpu, &segment, seg); + + c->src.val = segment.selector; +emulate_push (ctxt); +} + +static int emulate_pop_sreg (struct x86_emulate_ctxt *ctxt, +struct x86_emulate_ops *ops,int seg) +{ +struct decode_cache *c = &ctxt->decode; +struct kvm_segment segment; +int rc; + +if (ctxt->mode ==X86EMUL_MODE_PROT64 && (seg !=VCPU_SREG_FS || + seg !=VCPU_SREG_GS )) { +kvm_queue_exception (ctxt->vcpu,UD_VECTOR ); +return -1 ; + } + + kvm_x86_ops->get_segment (ctxt->vcpu, &segment, seg); + rc =emulate_pop (ctxt, ops, &segment.selector, c->op_bytes); +if (rc !=0 ) +return rc; + + rc =kvm_load_segment_descriptor (ctxt->vcpu, segment.selector,1 , seg); +return rc; +} +static inline int emulate_grp1a (struct x86_emulate_ctxt *ctxt,struct x86_emulate_ops *ops) {
@@ -1707,18 +1751,45 @@ special_insn: add:/* add */ emulate_2op_SrcV ("add" , c->src, c->dst, ctxt->eflags);break ; +case 0x06 :/* push es */ +emulate_push_sreg (ctxt,VCPU_SREG_ES ); +break ; +case 0x07 :/* pop es */ + rc =emulate_pop_sreg (ctxt, ops,VCPU_SREG_ES ); +if (rc !=0 ) + goto done; +break ; case 0x08 ... 0x0d: or:/* or */ emulate_2op_SrcV ("or" , c->src, c->dst, ctxt->eflags);break ; +case 0x0e :/* push cs */ +emulate_push_sreg (ctxt,VCPU_SREG_CS ); +break ; case 0x10 ... 0x15: adc:/* adc */ emulate_2op_SrcV ("adc" , c->src, c->dst, ctxt->eflags);break ; +case 0x16 :/* push ss */ +emulate_push_sreg (ctxt,VCPU_SREG_SS ); +break ; +case 0x17 :/* pop ss */ + rc =emulate_pop_sreg (ctxt, ops,VCPU_SREG_SS ); +if (rc !=0 ) + goto done; +break ; case 0x18 ... 0x1d: sbb:/* sbb */ emulate_2op_SrcV ("sbb" , c->src, c->dst, ctxt->eflags);break ; +case 0x1e :/* push ds */ +emulate_push_sreg (ctxt,VCPU_SREG_DS ); +break ; +case 0x1f :/* pop ds */ + rc =emulate_pop_sreg (ctxt, ops,VCPU_SREG_DS ); +if (rc !=0 ) + goto done; +break ; case 0x20 ... 0x25: and:/* and */ emulate_2op_SrcV ("and" , c->src, c->dst, ctxt->eflags);
@@ -2297,6 +2368,14 @@ twobyte_insn:jmp_rel (c, c->src.val); c->dst.type =OP_NONE ;break ; +case 0xa0 :/* push fs */ +emulate_push_sreg (ctxt,VCPU_SREG_FS ); +break ; +case 0xa1 :/* pop fs */ + rc =emulate_pop_sreg (ctxt, ops,VCPU_SREG_FS ); +if (rc !=0 ) + goto done; +break ;case 0xa3 : bt:/* bt */ c->dst.type =OP_NONE ;
@@ -2308,6 +2387,14 @@ twobyte_insn:case 0xa5 :/* shld cl, r, r/m */ emulate_2op_cl ("shld" , c->src2, c->src, c->dst, ctxt->eflags);break ; +case 0xa8 :/* push gs */ +emulate_push_sreg (ctxt,VCPU_SREG_GS ); +break ; +case 0xa9 :/* pop gs */ + rc =emulate_pop_sreg (ctxt, ops,VCPU_SREG_GS ); +if (rc !=0 ) + goto done; +break ;case 0xab : bts:/* bts */ /* only subword offset */
Signature · 1 line
1.6.0.4
arch/x86/kvm/emulate.c static int emulate_pop(struct x86_emulate_ctxt *ctxt, · line 1203
Quoted 12 lines · Mohammed Gamal
arch/x86/kvm/emulate.c +10
-0+static void emulate_push_sreg (struct x86_emulate_ctxt *ctxt,int seg) +{ +struct decode_cache *c =&ctxt->decode; +struct kvm_segment segment; + +if (ctxt->mode ==X86EMUL_MODE_PROT64 && (seg !=VCPU_SREG_FS || + seg !=VCPU_SREG_GS )) { +kvm_queue_exception (ctxt->vcpu,UD_VECTOR ); +return ; + }
It's better to check at the callsite, in case the opcode is ever reused for a new instruction. Or even better, add a new decode flag No64 so we can do this during the decode stage.
Quoted 13 lines
arch/x86/kvm/emulate.c +12
-0+ +static int emulate_pop_sreg (struct x86_emulate_ctxt *ctxt, +struct x86_emulate_ops *ops,int seg) +{ +struct decode_cache *c =&ctxt->decode; +struct kvm_segment segment; +int rc; + +if (ctxt->mode ==X86EMUL_MODE_PROT64 && (seg !=VCPU_SREG_FS || + seg !=VCPU_SREG_GS )) { +kvm_queue_exception (ctxt->vcpu,UD_VECTOR ); +return -1 ;
arch/x86/kvm/emulate.c static int emulate_pop(struct x86_emulate_ctxt *ctxt, · line 1231
Quoted 10 lines
arch/x86/kvm/emulate.c +10
-0+ } + + kvm_x86_ops->get_segment (ctxt->vcpu,&segment, seg); + rc =emulate_pop (ctxt, ops,&segment.selector, c->op_bytes); +if (rc !=0 ) +return rc; + + rc =kvm_load_segment_descriptor (ctxt->vcpu, segment.selector,1 , seg); +return rc; +}
Why do the ->get_segment() at all? pop into a temporary variable, and call kvm_load_segment_descriptor() with that.
Signature · 1 line
error compiling committee.c: too many arguments to function
Quoted 17 lines · Avi Kivity
arch/x86/kvm/emulate.c static int emulate_pop(struct x86_emulate_ctxt *ctxt, · line 1203
Quoted 12 lines · Mohammed Gamal
arch/x86/kvm/emulate.c +10
-0+static void emulate_push_sreg (struct x86_emulate_ctxt *ctxt,int seg) +{ + struct decode_cache *c =&ctxt->decode; + struct kvm_segment segment; + + if (ctxt->mode == X86EMUL_MODE_PROT64&& (seg != VCPU_SREG_FS || + seg != VCPU_SREG_GS)) { + kvm_queue_exception(ctxt->vcpu, UD_VECTOR); + return; + }It's better to check at the callsite, in case the opcode is ever reused for a new instruction. Or even better, add a new decode flag No64 so we can do this during the decode stage.
Good idea, but I believe it'd be better to introduce it in a separate patch so that we can update all instructions incompatible with long mode in one go. I'll move the checks to the call site for the time being.
Quoted 35 lines
Quoted 22 lines
arch/x86/kvm/emulate.c +10
-0+ +static int emulate_pop_sreg (struct x86_emulate_ctxt *ctxt, + struct x86_emulate_ops *ops, int seg) +{ + struct decode_cache *c =&ctxt->decode; + struct kvm_segment segment; + int rc; + + if (ctxt->mode == X86EMUL_MODE_PROT64&& (seg != VCPU_SREG_FS || + seg != VCPU_SREG_GS)){
+kvm_queue_exception(ctxt->vcpu, UD_VECTOR);
+ return -1;
+ }arch/x86/kvm/emulate.c +7
-0+ + kvm_x86_ops->get_segment(ctxt->vcpu,&segment, seg); + rc = emulate_pop(ctxt, ops,&segment.selector, c->op_bytes); + if (rc != 0) + return rc; + + rc = kvm_load_segment_descriptor(ctxt->vcpu, segment.selector, 1,Quoted 4 lines
seg);
+ return rc;
+}Why do the ->get_segment() at all? pop into a temporary variable, and call
kvm_load_segment_descriptor()with that.--
error compilingcommittee.c: too many arguments to function
Quoted 17 lines · Mohammed Gamal
Quoted 17 lines
arch/x86/kvm/emulate.c static int emulate_pop(struct x86_emulate_ctxt *ctxt, · line 1203
Quoted 13 lines
arch/x86/kvm/emulate.c +10
-0+static void emulate_push_sreg (struct x86_emulate_ctxt *ctxt,int seg) +{ +struct decode_cache *c =&ctxt->decode; +struct kvm_segment segment; + +if (ctxt->mode ==X86EMUL_MODE_PROT64 && (seg !=VCPU_SREG_FS || + seg !=VCPU_SREG_GS )) { +kvm_queue_exception (ctxt->vcpu,UD_VECTOR ); +return ; + }It's better to check at the callsite, in case the opcode is ever reused for a new instruction. Or even better, add a new decode flag No64 so we can do this during the decode stage.
Quoted 5 lines
Good idea, but I believe it'd be better to introduce it in a separate patch so that we can update all instructions incompatible with long mode in one go. I'll move the checks to the call site for the time being.
Sure. Or do the No64 patch first.
Signature · 1 line
error compiling committee.c: too many arguments to function