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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 2/4] x86emul: consolidate segment register handling
Use a single set of variables throughout the huge switch() statement,
allowing to funnel SLDT/STR into the mov-from-sreg code path.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
v2: s/store_seg/store_selector/g. Re-base.
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2505,7 +2505,8 @@ x86_emulate(
switch ( ctxt->opcode )
{
- struct segment_register cs;
+ enum x86_segment seg;
+ struct segment_register cs, sreg;
case 0x00 ... 0x05: add: /* add */
emulate_2op_SrcV("add", src, dst, _regs.eflags);
@@ -2541,22 +2542,20 @@ x86_emulate(
dst.type = OP_NONE;
break;
- case 0x06: /* push %%es */ {
- struct segment_register reg;
+ case 0x06: /* push %%es */
src.val = x86_seg_es;
push_seg:
generate_exception_if(mode_64bit() && !ext, EXC_UD, -1);
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(src.val, ®, ctxt)) != 0 )
+ if ( (rc = ops->read_segment(src.val, &sreg, ctxt)) != 0 )
goto done;
/* 64-bit mode: PUSH defaults to a 64-bit operand. */
if ( mode_64bit() && (op_bytes == 4) )
op_bytes = 8;
if ( (rc = ops->write(x86_seg_ss, sp_pre_dec(op_bytes),
- ®.sel, op_bytes, ctxt)) != 0 )
+ &sreg.sel, op_bytes, ctxt)) != 0 )
goto done;
break;
- }
case 0x07: /* pop %%es */
src.val = x86_seg_es;
@@ -2872,21 +2871,20 @@ x86_emulate(
dst.val = src.val;
break;
- case 0x8c: /* mov Sreg,r/m */ {
- struct segment_register reg;
- enum x86_segment seg = decode_segment(modrm_reg);
+ case 0x8c: /* mov Sreg,r/m */
+ seg = decode_segment(modrm_reg);
generate_exception_if(seg == decode_segment_failed, EXC_UD, -1);
+ store_selector:
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(seg, ®, ctxt)) != 0 )
+ if ( (rc = ops->read_segment(seg, &sreg, ctxt)) != 0 )
goto done;
- dst.val = reg.sel;
+ dst.val = sreg.sel;
if ( dst.type == OP_MEM )
dst.bytes = 2;
break;
- }
- case 0x8e: /* mov r/m,Sreg */ {
- enum x86_segment seg = decode_segment(modrm_reg);
+ case 0x8e: /* mov r/m,Sreg */
+ seg = decode_segment(modrm_reg);
generate_exception_if(seg == decode_segment_failed, EXC_UD, -1);
generate_exception_if(seg == x86_seg_cs, EXC_UD, -1);
if ( (rc = load_seg(seg, src.val, 0, NULL, ctxt, ops)) != 0 )
@@ -2895,7 +2893,6 @@ x86_emulate(
ctxt->retire.flags.mov_ss = 1;
dst.type = OP_NONE;
break;
- }
case 0x8d: /* lea */
generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
@@ -2952,17 +2949,15 @@ x86_emulate(
}
break;
- case 0x9a: /* call (far, absolute) */ {
- struct segment_register reg;
-
+ case 0x9a: /* call (far, absolute) */
ASSERT(!mode_64bit());
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(x86_seg_cs, ®, ctxt)) ||
+ if ( (rc = ops->read_segment(x86_seg_cs, &sreg, ctxt)) ||
(rc = load_seg(x86_seg_cs, imm2, 0, &cs, ctxt, ops)) ||
(validate_far_branch(&cs, imm1),
rc = ops->write(x86_seg_ss, sp_pre_dec(op_bytes),
- ®.sel, op_bytes, ctxt)) ||
+ &sreg.sel, op_bytes, ctxt)) ||
(rc = ops->write(x86_seg_ss, sp_pre_dec(op_bytes),
&_regs.eip, op_bytes, ctxt)) ||
(rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) )
@@ -2970,7 +2965,6 @@ x86_emulate(
_regs.eip = imm1;
break;
- }
case 0x9b: /* wait/fwait */
emulate_fpu_insn("fwait");
@@ -4179,13 +4173,12 @@ x86_emulate(
if ( (modrm_reg & 7) == 3 ) /* call */
{
- struct segment_register reg;
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(x86_seg_cs, ®, ctxt)) ||
+ if ( (rc = ops->read_segment(x86_seg_cs, &sreg, ctxt)) ||
(rc = load_seg(x86_seg_cs, sel, 0, &cs, ctxt, ops)) ||
(validate_far_branch(&cs, src.val),
rc = ops->write(x86_seg_ss, sp_pre_dec(op_bytes),
- ®.sel, op_bytes, ctxt)) ||
+ &sreg.sel, op_bytes, ctxt)) ||
(rc = ops->write(x86_seg_ss, sp_pre_dec(op_bytes),
&_regs.eip, op_bytes, ctxt)) ||
(rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) )
@@ -4207,23 +4200,13 @@ x86_emulate(
break;
case X86EMUL_OPC(0x0f, 0x00): /* Grp6 */
- {
- enum x86_segment seg = (modrm_reg & 1) ? x86_seg_tr : x86_seg_ldtr;
-
+ seg = (modrm_reg & 1) ? x86_seg_tr : x86_seg_ldtr;
generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
switch ( modrm_reg & 6 )
{
- struct segment_register sreg;
-
case 0: /* sldt / str */
generate_exception_if(umip_active(ctxt, ops), EXC_GP, 0);
- fail_if(!ops->read_segment);
- if ( (rc = ops->read_segment(seg, &sreg, ctxt)) != 0 )
- goto done;
- dst.val = sreg.sel;
- if ( dst.type == OP_MEM )
- dst.bytes = 2;
- break;
+ goto store_selector;
case 2: /* lldt / ltr */
generate_exception_if(!mode_ring0(), EXC_GP, 0);
if ( (rc = load_seg(seg, src.val, 0, NULL, ctxt, ops)) != 0 )
@@ -4234,10 +4217,8 @@ x86_emulate(
break;
}
break;
- }
case X86EMUL_OPC(0x0f, 0x01): /* Grp7 */ {
- struct segment_register reg;
unsigned long base, limit, cr0, cr0w;
switch( modrm )
@@ -4326,6 +4307,8 @@ x86_emulate(
}
}
+ seg = (modrm_reg & 1) ? x86_seg_idtr : x86_seg_gdtr;
+
switch ( modrm_reg & 7 )
{
case 0: /* sgdt */
@@ -4333,16 +4316,14 @@ x86_emulate(
generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
generate_exception_if(umip_active(ctxt, ops), EXC_GP, 0);
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment((modrm_reg & 1) ?
- x86_seg_idtr : x86_seg_gdtr,
- ®, ctxt)) )
+ if ( (rc = ops->read_segment(seg, &sreg, ctxt)) )
goto done;
if ( op_bytes == 2 )
- reg.base &= 0xffffff;
+ sreg.base &= 0xffffff;
if ( (rc = ops->write(ea.mem.seg, ea.mem.off+0,
- ®.limit, 2, ctxt)) ||
+ &sreg.limit, 2, ctxt)) ||
(rc = ops->write(ea.mem.seg, ea.mem.off+2,
- ®.base, mode_64bit() ? 8 : 4, ctxt)) )
+ &sreg.base, mode_64bit() ? 8 : 4, ctxt)) )
goto done;
break;
case 2: /* lgdt */
@@ -4350,19 +4331,17 @@ x86_emulate(
generate_exception_if(!mode_ring0(), EXC_GP, 0);
generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
fail_if(ops->write_segment == NULL);
- memset(®, 0, sizeof(reg));
+ memset(&sreg, 0, sizeof(sreg));
if ( (rc = read_ulong(ea.mem.seg, ea.mem.off+0,
&limit, 2, ctxt, ops)) ||
(rc = read_ulong(ea.mem.seg, ea.mem.off+2,
&base, mode_64bit() ? 8 : 4, ctxt, ops)) )
goto done;
- reg.base = base;
- reg.limit = limit;
+ sreg.base = base;
+ sreg.limit = limit;
if ( op_bytes == 2 )
- reg.base &= 0xffffff;
- if ( (rc = ops->write_segment((modrm_reg & 1) ?
- x86_seg_idtr : x86_seg_gdtr,
- ®, ctxt)) )
+ sreg.base &= 0xffffff;
+ if ( (rc = ops->write_segment(seg, &sreg, ctxt)) )
goto done;
break;
case 4: /* smsw */
@@ -4405,7 +4384,6 @@ x86_emulate(
case X86EMUL_OPC(0x0f, 0x05): /* syscall */ {
uint64_t msr_content;
- struct segment_register cs, ss;
generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
@@ -4419,11 +4397,11 @@ x86_emulate(
goto done;
cs.sel = (msr_content >> 32) & ~3; /* SELECTOR_RPL_MASK */
- ss.sel = cs.sel + 8;
+ sreg.sel = cs.sel + 8;
- cs.base = ss.base = 0; /* flat segment */
- cs.limit = ss.limit = ~0u; /* 4GB limit */
- ss.attr.bytes = 0xc93; /* G+DB+P+S+Data */
+ cs.base = sreg.base = 0; /* flat segment */
+ cs.limit = sreg.limit = ~0u; /* 4GB limit */
+ sreg.attr.bytes = 0xc93; /* G+DB+P+S+Data */
#ifdef __x86_64__
rc = in_longmode(ctxt, ops);
@@ -4457,7 +4435,7 @@ x86_emulate(
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) ||
- (rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) )
+ (rc = ops->write_segment(x86_seg_ss, &sreg, ctxt)) )
goto done;
break;
@@ -4676,7 +4654,6 @@ x86_emulate(
case X86EMUL_OPC(0x0f, 0x34): /* sysenter */ {
uint64_t msr_content;
- struct segment_register cs, ss;
int lm;
generate_exception_if(mode_ring0(), EXC_GP, 0);
@@ -4701,14 +4678,14 @@ x86_emulate(
cs.attr.bytes = lm ? 0xa9b /* L+DB+P+S+Code */
: 0xc9b; /* G+DB+P+S+Code */
- ss.sel = cs.sel + 8;
- ss.base = 0; /* flat segment */
- ss.limit = ~0u; /* 4GB limit */
- ss.attr.bytes = 0xc93; /* G+DB+P+S+Data */
+ sreg.sel = cs.sel + 8;
+ sreg.base = 0; /* flat segment */
+ sreg.limit = ~0u; /* 4GB limit */
+ sreg.attr.bytes = 0xc93; /* G+DB+P+S+Data */
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) != 0 ||
- (rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) != 0 )
+ (rc = ops->write_segment(x86_seg_ss, &sreg, ctxt)) != 0 )
goto done;
if ( (rc = ops->read_msr(MSR_SYSENTER_EIP, &msr_content, ctxt)) != 0 )
@@ -4724,7 +4701,6 @@ x86_emulate(
case X86EMUL_OPC(0x0f, 0x35): /* sysexit */ {
uint64_t msr_content;
- struct segment_register cs, ss;
bool_t user64 = !!(rex_prefix & REX_W);
generate_exception_if(!mode_ring0(), EXC_GP, 0);
@@ -4746,14 +4722,14 @@ x86_emulate(
cs.attr.bytes = user64 ? 0xafb /* L+DB+P+DPL3+S+Code */
: 0xcfb; /* G+DB+P+DPL3+S+Code */
- ss.sel = cs.sel + 8;
- ss.base = 0; /* flat segment */
- ss.limit = ~0u; /* 4GB limit */
- ss.attr.bytes = 0xcf3; /* G+DB+P+DPL3+S+Data */
+ sreg.sel = cs.sel + 8;
+ sreg.base = 0; /* flat segment */
+ sreg.limit = ~0u; /* 4GB limit */
+ sreg.attr.bytes = 0xcf3; /* G+DB+P+DPL3+S+Data */
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) != 0 ||
- (rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) != 0 )
+ (rc = ops->write_segment(x86_seg_ss, &sreg, ctxt)) != 0 )
goto done;
_regs.eip = user64 ? _regs.edx : (uint32_t)_regs.edx;
Attachment:
x86emul-consolidate-sreg.patch _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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