Message ID | 1360402311-19904-7-git-send-email-avi.kivity@gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On Sat, Feb 09, 2013 at 11:31:49AM +0200, Avi Kivity wrote: > Since DIV and IDIV can generate exceptions, we need an additional output > parameter indicating whether an execption has occured. To avoid increasing > register pressure on i386, we use %rsi, which is already allocated for > the fastop code pointer. > > Signed-off-by: Avi Kivity <avi.kivity@gmail.com> > --- > arch/x86/kvm/emulate.c | 51 +++++++++++++++++++++++++------------------------- > 1 file changed, 26 insertions(+), 25 deletions(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 0f0c15e..89f56bb 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -180,6 +180,7 @@ > * src: rdx (in/out) > * src2: rcx (in) > * flags: rflags (in/out) > + * ex: rsi (in:nonzero, out:zero if exception) in:fastop pointer, or "code pointer" may be? > * > * Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for > * different operand sizes can be reached by calculation, rather than a jump > @@ -467,7 +468,10 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); > #define FOPNOP() FOP_ALIGN FOP_RET > > #define FOP1E(op, dst) \ > - FOP_ALIGN #op " %" #dst " \n\t" FOP_RET > + FOP_ALIGN "10: " #op " %" #dst " \n\t" FOP_RET > + > +#define FOP1EEX(op, dst) \ > + FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception) > > #define FASTOP1(op) \ > FOP_START(op) \ > @@ -486,6 +490,15 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); > ON64(FOP1E(op, rcx)) \ > FOP_END > > +/* 1-operand, using src2 (for MUL/DIV r/m), with exceptions */ > +#define FASTOP1SRC2EX(op, name) \ > + FOP_START(name) \ > + FOP1EEX(op, cl) \ > + FOP1EEX(op, cx) \ > + FOP1EEX(op, ecx) \ > + ON64(FOP1EEX(op, rcx)) \ > + FOP_END > + > #define FOP2E(op, dst, src) \ > FOP_ALIGN #op " %" #src ", %" #dst " \n\t" FOP_RET > > @@ -530,6 +543,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); > /* Special case for SETcc - 1 instruction per cc */ > #define FOP_SETCC(op) ".align 4; " #op " %al; ret \n\t" > > +asm(".global kvm_fastop_exception \n" > + "kvm_fastop_exception: xor %esi, %esi; ret"); > + > FOP_START(setcc) > FOP_SETCC(seto) > FOP_SETCC(setno) > @@ -1001,6 +1017,8 @@ FASTOP2(test); > > FASTOP1SRC2(mul, mul_ex); > FASTOP1SRC2(imul, imul_ex); > +FASTOP1SRC2EX(div, div_ex); > +FASTOP1SRC2EX(idiv, idiv_ex); > > FASTOP3WCL(shld); > FASTOP3WCL(shrd); > @@ -2116,26 +2134,6 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt) > return X86EMUL_CONTINUE; > } > > -static int em_div_ex(struct x86_emulate_ctxt *ctxt) > -{ > - u8 de = 0; > - > - emulate_1op_rax_rdx(ctxt, "div", de); > - if (de) > - return emulate_de(ctxt); > - return X86EMUL_CONTINUE; > -} > - > -static int em_idiv_ex(struct x86_emulate_ctxt *ctxt) > -{ > - u8 de = 0; > - > - emulate_1op_rax_rdx(ctxt, "idiv", de); > - if (de) > - return emulate_de(ctxt); > - return X86EMUL_CONTINUE; > -} > - > static int em_grp45(struct x86_emulate_ctxt *ctxt) > { > int rc = X86EMUL_CONTINUE; > @@ -3700,8 +3698,8 @@ static const struct opcode group3[] = { > F(DstMem | SrcNone | Lock, em_neg), > F(DstXacc | Src2Mem, em_mul_ex), > F(DstXacc | Src2Mem, em_imul_ex), > - I(DstXacc | Src2Mem, em_div_ex), > - I(DstXacc | Src2Mem, em_idiv_ex), > + F(DstXacc | Src2Mem, em_div_ex), > + F(DstXacc | Src2Mem, em_idiv_ex), > }; > > static const struct opcode group4[] = { > @@ -4518,9 +4516,12 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) > if (!(ctxt->d & ByteOp)) > fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; > asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" > - : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags) > - : "c"(ctxt->src2.val), [fastop]"S"(fop)); > + : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags), > + [fastop]"+S"(fop) > + : "c"(ctxt->src2.val)); > ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); > + if (!fop) Looks like this magic deserves at least a short comment :) > + return emulate_de(ctxt); > return X86EMUL_CONTINUE; > } > > -- > 1.8.1.2 -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 0f0c15e..89f56bb 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -180,6 +180,7 @@ * src: rdx (in/out) * src2: rcx (in) * flags: rflags (in/out) + * ex: rsi (in:nonzero, out:zero if exception) * * Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for * different operand sizes can be reached by calculation, rather than a jump @@ -467,7 +468,10 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); #define FOPNOP() FOP_ALIGN FOP_RET #define FOP1E(op, dst) \ - FOP_ALIGN #op " %" #dst " \n\t" FOP_RET + FOP_ALIGN "10: " #op " %" #dst " \n\t" FOP_RET + +#define FOP1EEX(op, dst) \ + FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception) #define FASTOP1(op) \ FOP_START(op) \ @@ -486,6 +490,15 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); ON64(FOP1E(op, rcx)) \ FOP_END +/* 1-operand, using src2 (for MUL/DIV r/m), with exceptions */ +#define FASTOP1SRC2EX(op, name) \ + FOP_START(name) \ + FOP1EEX(op, cl) \ + FOP1EEX(op, cx) \ + FOP1EEX(op, ecx) \ + ON64(FOP1EEX(op, rcx)) \ + FOP_END + #define FOP2E(op, dst, src) \ FOP_ALIGN #op " %" #src ", %" #dst " \n\t" FOP_RET @@ -530,6 +543,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)); /* Special case for SETcc - 1 instruction per cc */ #define FOP_SETCC(op) ".align 4; " #op " %al; ret \n\t" +asm(".global kvm_fastop_exception \n" + "kvm_fastop_exception: xor %esi, %esi; ret"); + FOP_START(setcc) FOP_SETCC(seto) FOP_SETCC(setno) @@ -1001,6 +1017,8 @@ FASTOP2(test); FASTOP1SRC2(mul, mul_ex); FASTOP1SRC2(imul, imul_ex); +FASTOP1SRC2EX(div, div_ex); +FASTOP1SRC2EX(idiv, idiv_ex); FASTOP3WCL(shld); FASTOP3WCL(shrd); @@ -2116,26 +2134,6 @@ static int em_jmp_far(struct x86_emulate_ctxt *ctxt) return X86EMUL_CONTINUE; } -static int em_div_ex(struct x86_emulate_ctxt *ctxt) -{ - u8 de = 0; - - emulate_1op_rax_rdx(ctxt, "div", de); - if (de) - return emulate_de(ctxt); - return X86EMUL_CONTINUE; -} - -static int em_idiv_ex(struct x86_emulate_ctxt *ctxt) -{ - u8 de = 0; - - emulate_1op_rax_rdx(ctxt, "idiv", de); - if (de) - return emulate_de(ctxt); - return X86EMUL_CONTINUE; -} - static int em_grp45(struct x86_emulate_ctxt *ctxt) { int rc = X86EMUL_CONTINUE; @@ -3700,8 +3698,8 @@ static const struct opcode group3[] = { F(DstMem | SrcNone | Lock, em_neg), F(DstXacc | Src2Mem, em_mul_ex), F(DstXacc | Src2Mem, em_imul_ex), - I(DstXacc | Src2Mem, em_div_ex), - I(DstXacc | Src2Mem, em_idiv_ex), + F(DstXacc | Src2Mem, em_div_ex), + F(DstXacc | Src2Mem, em_idiv_ex), }; static const struct opcode group4[] = { @@ -4518,9 +4516,12 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) if (!(ctxt->d & ByteOp)) fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" - : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags) - : "c"(ctxt->src2.val), [fastop]"S"(fop)); + : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags), + [fastop]"+S"(fop) + : "c"(ctxt->src2.val)); ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); + if (!fop) + return emulate_de(ctxt); return X86EMUL_CONTINUE; }
Since DIV and IDIV can generate exceptions, we need an additional output parameter indicating whether an execption has occured. To avoid increasing register pressure on i386, we use %rsi, which is already allocated for the fastop code pointer. Signed-off-by: Avi Kivity <avi.kivity@gmail.com> --- arch/x86/kvm/emulate.c | 51 +++++++++++++++++++++++++------------------------- 1 file changed, 26 insertions(+), 25 deletions(-)