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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 16/17] x86emul: make all FPU emulation use the stub
While this means quite some reduction of (source) code, the main
purpose is to no longer have exceptions raised from other than stubs.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -1261,28 +1261,25 @@ static inline bool fpu_check_write(void)
return !(fsw & FSW_ES);
}
-#define emulate_fpu_insn(_op) \
- asm volatile ( \
- "movb $2f-1f,%0 \n" \
- "1: " _op " \n" \
- "2: \n" \
- : "=m" (fic.insn_bytes) : : "memory" )
-
-#define emulate_fpu_insn_memdst(_op, _arg) \
- asm volatile ( \
- "movb $2f-1f,%0 \n" \
- "1: " _op " %1 \n" \
- "2: \n" \
- : "=m" (fic.insn_bytes), "=m" (_arg) \
- : : "memory" )
-
-#define emulate_fpu_insn_memsrc(_op, _arg) \
- asm volatile ( \
- "movb $2f-1f,%0 \n" \
- "1: " _op " %1 \n" \
- "2: \n" \
- : "=m" (fic.insn_bytes) \
- : "m" (_arg) : "memory" )
+#define emulate_fpu_insn_memdst(opc, ext, arg) \
+do { \
+ /* ModRM: mod=0, reg=ext, rm=0, i.e. a (%rax) operand */ \
+ fic.insn_bytes = 2; \
+ memcpy(get_stub(stub), \
+ ((uint8_t[]){ opc, ((ext) & 7) << 3, 0xc3 }), 3); \
+ invoke_stub("", "", "+m" (fic), "+m" (arg) : "a" (&(arg))); \
+ put_stub(stub); \
+} while (0)
+
+#define emulate_fpu_insn_memsrc(opc, ext, arg) \
+do { \
+ /* ModRM: mod=0, reg=ext, rm=0, i.e. a (%rax) operand */ \
+ fic.insn_bytes = 2; \
+ memcpy(get_stub(stub), \
+ ((uint8_t[]){ opc, ((ext) & 7) << 3, 0xc3 }), 3); \
+ invoke_stub("", "", "+m" (fic) : "m" (arg), "a" (&(arg))); \
+ put_stub(stub); \
+} while (0)
#define emulate_fpu_insn_stub(bytes...) \
do { \
@@ -3834,8 +3831,7 @@ x86_emulate(
case 0x9b: /* wait/fwait */
host_and_vcpu_must_have(fpu);
get_fpu(X86EMUL_FPU_wait, &fic);
- fic.insn_bytes = 1;
- asm volatile ( "fwait" ::: "memory" );
+ emulate_fpu_insn_stub(b);
check_fpu_exn(&fic);
break;
@@ -4253,37 +4249,13 @@ x86_emulate(
emulate_fpu_insn_stub(0xd8, modrm);
break;
default:
+ fpu_memsrc32:
ASSERT(ea.type == OP_MEM);
if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
4, ctxt)) != X86EMUL_OKAY )
goto done;
- switch ( modrm_reg & 7 )
- {
- case 0: /* fadd */
- emulate_fpu_insn_memsrc("fadds", src.val);
- break;
- case 1: /* fmul */
- emulate_fpu_insn_memsrc("fmuls", src.val);
- break;
- case 2: /* fcom */
- emulate_fpu_insn_memsrc("fcoms", src.val);
- break;
- case 3: /* fcomp */
- emulate_fpu_insn_memsrc("fcomps", src.val);
- break;
- case 4: /* fsub */
- emulate_fpu_insn_memsrc("fsubs", src.val);
- break;
- case 5: /* fsubr */
- emulate_fpu_insn_memsrc("fsubrs", src.val);
- break;
- case 6: /* fdiv */
- emulate_fpu_insn_memsrc("fdivs", src.val);
- break;
- case 7: /* fdivr */
- emulate_fpu_insn_memsrc("fdivrs", src.val);
- break;
- }
+ emulate_fpu_insn_memsrc(b, modrm_reg, src.val);
+ break;
}
check_fpu_exn(&fic);
break;
@@ -4330,52 +4302,46 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- dst = ea;
switch ( modrm_reg & 7 )
{
case 0: /* fld m32fp */
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 4, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("flds", src.val);
- dst.type = OP_NONE;
- break;
+ goto fpu_memsrc32;
case 2: /* fst m32fp */
- emulate_fpu_insn_memdst("fsts", dst.val);
- dst.bytes = 4;
- break;
case 3: /* fstp m32fp */
- emulate_fpu_insn_memdst("fstps", dst.val);
+ fpu_memdst32:
+ dst = ea;
dst.bytes = 4;
+ emulate_fpu_insn_memdst(b, modrm_reg, dst.val);
break;
case 4: /* fldenv - TODO */
state->fpu_ctrl = true;
goto cannot_emulate;
case 5: /* fldcw m2byte */
state->fpu_ctrl = true;
+ fpu_memsrc16:
if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
2, ctxt)) != X86EMUL_OKAY )
goto done;
- emulate_fpu_insn_memsrc("fldcw", src.val);
- dst.type = OP_NONE;
+ emulate_fpu_insn_memsrc(b, modrm_reg, src.val);
break;
case 6: /* fnstenv - TODO */
state->fpu_ctrl = true;
goto cannot_emulate;
case 7: /* fnstcw m2byte */
state->fpu_ctrl = true;
- emulate_fpu_insn_memdst("fnstcw", dst.val);
+ fpu_memdst16:
+ dst = ea;
dst.bytes = 2;
+ emulate_fpu_insn_memdst(b, modrm_reg, dst.val);
break;
default:
generate_exception(EXC_UD);
}
/*
* Control instructions can't raise FPU exceptions, so we need
- * to consider suppressing writes only for non-control ones. All
- * of them in this group have data width 4.
+ * to consider suppressing writes only for non-control ones.
*/
- if ( dst.type == OP_MEM && dst.bytes == 4 && !fpu_check_write() )
+ if ( dst.type == OP_MEM && !state->fpu_ctrl && !fpu_check_write() )
dst.type = OP_NONE;
}
check_fpu_exn(&fic);
@@ -4398,36 +4364,7 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 4, ctxt)) != X86EMUL_OKAY )
- goto done;
- switch ( modrm_reg & 7 )
- {
- case 0: /* fiadd m32i */
- emulate_fpu_insn_memsrc("fiaddl", src.val);
- break;
- case 1: /* fimul m32i */
- emulate_fpu_insn_memsrc("fimull", src.val);
- break;
- case 2: /* ficom m32i */
- emulate_fpu_insn_memsrc("ficoml", src.val);
- break;
- case 3: /* ficomp m32i */
- emulate_fpu_insn_memsrc("ficompl", src.val);
- break;
- case 4: /* fisub m32i */
- emulate_fpu_insn_memsrc("fisubl", src.val);
- break;
- case 5: /* fisubr m32i */
- emulate_fpu_insn_memsrc("fisubrl", src.val);
- break;
- case 6: /* fidiv m32i */
- emulate_fpu_insn_memsrc("fidivl", src.val);
- break;
- case 7: /* fidivr m32i */
- emulate_fpu_insn_memsrc("fidivrl", src.val);
- break;
- }
+ goto fpu_memsrc32;
}
check_fpu_exn(&fic);
break;
@@ -4457,50 +4394,35 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- dst = ea;
switch ( modrm_reg & 7 )
{
case 0: /* fild m32i */
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 4, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("fildl", src.val);
- dst.type = OP_NONE;
- break;
+ goto fpu_memsrc32;
case 1: /* fisttp m32i */
host_and_vcpu_must_have(sse3);
- emulate_fpu_insn_memdst("fisttpl", dst.val);
- dst.bytes = 4;
- break;
+ /* fall through */
case 2: /* fist m32i */
- emulate_fpu_insn_memdst("fistl", dst.val);
- dst.bytes = 4;
- break;
case 3: /* fistp m32i */
- emulate_fpu_insn_memdst("fistpl", dst.val);
- dst.bytes = 4;
- break;
+ goto fpu_memdst32;
case 5: /* fld m80fp */
+ fpu_memsrc80:
if ( (rc = ops->read(ea.mem.seg, ea.mem.off, mmvalp,
10, ctxt)) != X86EMUL_OKAY )
goto done;
- emulate_fpu_insn_memsrc("fldt", *mmvalp);
- dst.type = OP_NONE;
+ emulate_fpu_insn_memsrc(b, modrm_reg, *mmvalp);
break;
case 7: /* fstp m80fp */
+ fpu_memdst80:
fail_if(!ops->write);
- emulate_fpu_insn_memdst("fstpt", *mmvalp);
+ emulate_fpu_insn_memdst(b, modrm_reg, *mmvalp);
if ( fpu_check_write() &&
(rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
10, ctxt)) != X86EMUL_OKAY )
goto done;
- dst.type = OP_NONE;
break;
default:
generate_exception(EXC_UD);
}
- if ( dst.type == OP_MEM && !fpu_check_write() )
- dst.type = OP_NONE;
}
check_fpu_exn(&fic);
break;
@@ -4521,37 +4443,13 @@ x86_emulate(
emulate_fpu_insn_stub(0xdc, modrm);
break;
default:
+ fpu_memsrc64:
ASSERT(ea.type == OP_MEM);
if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
8, ctxt)) != X86EMUL_OKAY )
goto done;
- switch ( modrm_reg & 7 )
- {
- case 0: /* fadd m64fp */
- emulate_fpu_insn_memsrc("faddl", src.val);
- break;
- case 1: /* fmul m64fp */
- emulate_fpu_insn_memsrc("fmull", src.val);
- break;
- case 2: /* fcom m64fp */
- emulate_fpu_insn_memsrc("fcoml", src.val);
- break;
- case 3: /* fcomp m64fp */
- emulate_fpu_insn_memsrc("fcompl", src.val);
- break;
- case 4: /* fsub m64fp */
- emulate_fpu_insn_memsrc("fsubl", src.val);
- break;
- case 5: /* fsubr m64fp */
- emulate_fpu_insn_memsrc("fsubrl", src.val);
- break;
- case 6: /* fdiv m64fp */
- emulate_fpu_insn_memsrc("fdivl", src.val);
- break;
- case 7: /* fdivr m64fp */
- emulate_fpu_insn_memsrc("fdivrl", src.val);
- break;
- }
+ emulate_fpu_insn_memsrc(b, modrm_reg, src.val);
+ break;
}
check_fpu_exn(&fic);
break;
@@ -4571,28 +4469,19 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- dst = ea;
switch ( modrm_reg & 7 )
{
case 0: /* fld m64fp */;
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 8, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("fldl", src.val);
- dst.type = OP_NONE;
- break;
+ goto fpu_memsrc64;
case 1: /* fisttp m64i */
host_and_vcpu_must_have(sse3);
- emulate_fpu_insn_memdst("fisttpll", dst.val);
- dst.bytes = 8;
- break;
+ /* fall through */
case 2: /* fst m64fp */
- emulate_fpu_insn_memdst("fstl", dst.val);
- dst.bytes = 8;
- break;
case 3: /* fstp m64fp */
- emulate_fpu_insn_memdst("fstpl", dst.val);
+ fpu_memdst64:
+ dst = ea;
dst.bytes = 8;
+ emulate_fpu_insn_memdst(b, modrm_reg, dst.val);
break;
case 4: /* frstor - TODO */
case 6: /* fnsave - TODO */
@@ -4600,18 +4489,15 @@ x86_emulate(
goto cannot_emulate;
case 7: /* fnstsw m2byte */
state->fpu_ctrl = true;
- emulate_fpu_insn_memdst("fnstsw", dst.val);
- dst.bytes = 2;
- break;
+ goto fpu_memdst16;
default:
generate_exception(EXC_UD);
}
/*
* Control instructions can't raise FPU exceptions, so we need
- * to consider suppressing writes only for non-control ones. All
- * of them in this group have data width 8.
+ * to consider suppressing writes only for non-control ones.
*/
- if ( dst.type == OP_MEM && dst.bytes == 8 && !fpu_check_write() )
+ if ( dst.type == OP_MEM && !state->fpu_ctrl && !fpu_check_write() )
dst.type = OP_NONE;
}
check_fpu_exn(&fic);
@@ -4634,33 +4520,8 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- switch ( modrm_reg & 7 )
- {
- case 0: /* fiadd m16i */
- emulate_fpu_insn_memsrc("fiadds", src.val);
- break;
- case 1: /* fimul m16i */
- emulate_fpu_insn_memsrc("fimuls", src.val);
- break;
- case 2: /* ficom m16i */
- emulate_fpu_insn_memsrc("ficoms", src.val);
- break;
- case 3: /* ficomp m16i */
- emulate_fpu_insn_memsrc("ficomps", src.val);
- break;
- case 4: /* fisub m16i */
- emulate_fpu_insn_memsrc("fisubs", src.val);
- break;
- case 5: /* fisubr m16i */
- emulate_fpu_insn_memsrc("fisubrs", src.val);
- break;
- case 6: /* fidiv m16i */
- emulate_fpu_insn_memsrc("fidivs", src.val);
- break;
- case 7: /* fidivr m16i */
- emulate_fpu_insn_memsrc("fidivrs", src.val);
- break;
- }
+ emulate_fpu_insn_memsrc(b, modrm_reg, src.val);
+ break;
}
check_fpu_exn(&fic);
break;
@@ -4676,7 +4537,7 @@ x86_emulate(
dst.bytes = 2;
dst.type = OP_REG;
dst.reg = (void *)&_regs.ax;
- emulate_fpu_insn_memdst("fnstsw", dst.val);
+ emulate_fpu_insn_memdst(b, modrm_reg, dst.val);
break;
case 0xe8 ... 0xef: /* fucomip %stN */
case 0xf0 ... 0xf7: /* fcomip %stN */
@@ -4691,59 +4552,26 @@ x86_emulate(
break;
default:
generate_exception_if(ea.type != OP_MEM, EXC_UD);
- dst = ea;
switch ( modrm_reg & 7 )
{
case 0: /* fild m16i */
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 2, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("filds", src.val);
- dst.type = OP_NONE;
- break;
+ goto fpu_memsrc16;
case 1: /* fisttp m16i */
host_and_vcpu_must_have(sse3);
- emulate_fpu_insn_memdst("fisttps", dst.val);
- dst.bytes = 2;
- break;
+ /* fall through */
case 2: /* fist m16i */
- emulate_fpu_insn_memdst("fists", dst.val);
- dst.bytes = 2;
- break;
case 3: /* fistp m16i */
- emulate_fpu_insn_memdst("fistps", dst.val);
- dst.bytes = 2;
- break;
+ goto fpu_memdst16;
case 4: /* fbld m80dec */
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, mmvalp,
- 10, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("fbld", *mmvalp);
- dst.type = OP_NONE;
- break;
+ goto fpu_memsrc80;
case 5: /* fild m64i */
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &src.val,
- 8, ctxt)) != X86EMUL_OKAY )
- goto done;
- emulate_fpu_insn_memsrc("fildll", src.val);
dst.type = OP_NONE;
- break;
+ goto fpu_memsrc64;
case 6: /* fbstp packed bcd */
- fail_if(!ops->write);
- emulate_fpu_insn_memdst("fbstp", *mmvalp);
- if ( fpu_check_write() &&
- (rc = ops->write(ea.mem.seg, ea.mem.off, mmvalp,
- 10, ctxt)) != X86EMUL_OKAY )
- goto done;
- dst.type = OP_NONE;
- break;
+ goto fpu_memdst80;
case 7: /* fistp m64i */
- emulate_fpu_insn_memdst("fistpll", dst.val);
- dst.bytes = 8;
- break;
+ goto fpu_memdst64;
}
- if ( dst.type == OP_MEM && !fpu_check_write() )
- dst.type = OP_NONE;
}
check_fpu_exn(&fic);
break;
Attachment:
x86emul-FPU-use-stub.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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