* [PATCH v2] x86emul: fold SReg PUSH/POP cases
@ 2016-12-08 11:40 Jan Beulich
2016-12-08 11:48 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2016-12-08 11:40 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper
[-- Attachment #1: Type: text/plain, Size: 3878 bytes --]
Now that segment registers are numbered naturally this can be easily
done to achieve some code size reduction.
Also consistently use X86EMUL_OKAY in the code being touched.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Set retire.mov_ss for "pop %ss" instead of "pop %es".
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2731,51 +2731,40 @@ x86_emulate(
break;
case 0x06: /* push %%es */
- src.val = x86_seg_es;
- push_seg:
- generate_exception_if(mode_64bit() && !ext, EXC_UD);
+ case 0x0e: /* push %%cs */
+ case 0x16: /* push %%ss */
+ case 0x1e: /* push %%ds */
+ generate_exception_if(mode_64bit(), EXC_UD);
+ /* fall through */
+ case X86EMUL_OPC(0x0f, 0xa0): /* push %%fs */
+ case X86EMUL_OPC(0x0f, 0xa8): /* push %%gs */
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(src.val, &sreg, ctxt)) != 0 )
+ if ( (rc = ops->read_segment((b >> 3) & 7, &sreg,
+ ctxt)) != X86EMUL_OKAY )
goto done;
src.val = sreg.sel;
goto push;
case 0x07: /* pop %%es */
- src.val = x86_seg_es;
- pop_seg:
- generate_exception_if(mode_64bit() && !ext, EXC_UD);
+ case 0x17: /* pop %%ss */
+ case 0x1f: /* pop %%ds */
+ generate_exception_if(mode_64bit(), EXC_UD);
+ /* fall through */
+ case X86EMUL_OPC(0x0f, 0xa1): /* pop %%fs */
+ case X86EMUL_OPC(0x0f, 0xa9): /* pop %%gs */
fail_if(ops->write_segment == NULL);
/* 64-bit mode: POP defaults to a 64-bit operand. */
if ( mode_64bit() && (op_bytes == 4) )
op_bytes = 8;
- if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(op_bytes),
- &dst.val, op_bytes, ctxt, ops)) != 0 ||
- (rc = load_seg(src.val, dst.val, 0, NULL, ctxt, ops)) != 0 )
+ seg = (b >> 3) & 7;
+ if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(op_bytes), &dst.val,
+ op_bytes, ctxt, ops)) != X86EMUL_OKAY ||
+ (rc = load_seg(seg, dst.val, 0, NULL, ctxt, ops)) != X86EMUL_OKAY )
goto done;
- if ( src.val == x86_seg_ss )
+ if ( seg == x86_seg_ss )
ctxt->retire.mov_ss = true;
break;
- case 0x0e: /* push %%cs */
- src.val = x86_seg_cs;
- goto push_seg;
-
- case 0x16: /* push %%ss */
- src.val = x86_seg_ss;
- goto push_seg;
-
- case 0x17: /* pop %%ss */
- src.val = x86_seg_ss;
- goto pop_seg;
-
- case 0x1e: /* push %%ds */
- src.val = x86_seg_ds;
- goto push_seg;
-
- case 0x1f: /* pop %%ds */
- src.val = x86_seg_ds;
- goto pop_seg;
-
case 0x27: /* daa */
case 0x2f: /* das */ {
uint8_t al = _regs.eax;
@@ -5137,14 +5126,6 @@ x86_emulate(
dst.val = test_cc(b, _regs.eflags);
break;
- case X86EMUL_OPC(0x0f, 0xa0): /* push %%fs */
- src.val = x86_seg_fs;
- goto push_seg;
-
- case X86EMUL_OPC(0x0f, 0xa1): /* pop %%fs */
- src.val = x86_seg_fs;
- goto pop_seg;
-
case X86EMUL_OPC(0x0f, 0xa2): /* cpuid */ {
unsigned int eax = _regs.eax, ebx = _regs.ebx;
unsigned int ecx = _regs.ecx, edx = _regs.edx;
@@ -5202,14 +5183,6 @@ x86_emulate(
break;
}
- case X86EMUL_OPC(0x0f, 0xa8): /* push %%gs */
- src.val = x86_seg_gs;
- goto push_seg;
-
- case X86EMUL_OPC(0x0f, 0xa9): /* pop %%gs */
- src.val = x86_seg_gs;
- goto pop_seg;
-
case X86EMUL_OPC(0x0f, 0xab): bts: /* bts */
emulate_2op_SrcV_nobyte("bts", src, dst, _regs.eflags);
break;
[-- Attachment #2: x86emul-fold-SReg-push-pop.patch --]
[-- Type: text/plain, Size: 3909 bytes --]
x86emul: fold SReg PUSH/POP cases
Now that segment registers are numbered naturally this can be easily
done to achieve some code size reduction.
Also consistently use X86EMUL_OKAY in the code being touched.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
v2: Set retire.mov_ss for "pop %ss" instead of "pop %es".
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2731,51 +2731,40 @@ x86_emulate(
break;
case 0x06: /* push %%es */
- src.val = x86_seg_es;
- push_seg:
- generate_exception_if(mode_64bit() && !ext, EXC_UD);
+ case 0x0e: /* push %%cs */
+ case 0x16: /* push %%ss */
+ case 0x1e: /* push %%ds */
+ generate_exception_if(mode_64bit(), EXC_UD);
+ /* fall through */
+ case X86EMUL_OPC(0x0f, 0xa0): /* push %%fs */
+ case X86EMUL_OPC(0x0f, 0xa8): /* push %%gs */
fail_if(ops->read_segment == NULL);
- if ( (rc = ops->read_segment(src.val, &sreg, ctxt)) != 0 )
+ if ( (rc = ops->read_segment((b >> 3) & 7, &sreg,
+ ctxt)) != X86EMUL_OKAY )
goto done;
src.val = sreg.sel;
goto push;
case 0x07: /* pop %%es */
- src.val = x86_seg_es;
- pop_seg:
- generate_exception_if(mode_64bit() && !ext, EXC_UD);
+ case 0x17: /* pop %%ss */
+ case 0x1f: /* pop %%ds */
+ generate_exception_if(mode_64bit(), EXC_UD);
+ /* fall through */
+ case X86EMUL_OPC(0x0f, 0xa1): /* pop %%fs */
+ case X86EMUL_OPC(0x0f, 0xa9): /* pop %%gs */
fail_if(ops->write_segment == NULL);
/* 64-bit mode: POP defaults to a 64-bit operand. */
if ( mode_64bit() && (op_bytes == 4) )
op_bytes = 8;
- if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(op_bytes),
- &dst.val, op_bytes, ctxt, ops)) != 0 ||
- (rc = load_seg(src.val, dst.val, 0, NULL, ctxt, ops)) != 0 )
+ seg = (b >> 3) & 7;
+ if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(op_bytes), &dst.val,
+ op_bytes, ctxt, ops)) != X86EMUL_OKAY ||
+ (rc = load_seg(seg, dst.val, 0, NULL, ctxt, ops)) != X86EMUL_OKAY )
goto done;
- if ( src.val == x86_seg_ss )
+ if ( seg == x86_seg_ss )
ctxt->retire.mov_ss = true;
break;
- case 0x0e: /* push %%cs */
- src.val = x86_seg_cs;
- goto push_seg;
-
- case 0x16: /* push %%ss */
- src.val = x86_seg_ss;
- goto push_seg;
-
- case 0x17: /* pop %%ss */
- src.val = x86_seg_ss;
- goto pop_seg;
-
- case 0x1e: /* push %%ds */
- src.val = x86_seg_ds;
- goto push_seg;
-
- case 0x1f: /* pop %%ds */
- src.val = x86_seg_ds;
- goto pop_seg;
-
case 0x27: /* daa */
case 0x2f: /* das */ {
uint8_t al = _regs.eax;
@@ -5137,14 +5126,6 @@ x86_emulate(
dst.val = test_cc(b, _regs.eflags);
break;
- case X86EMUL_OPC(0x0f, 0xa0): /* push %%fs */
- src.val = x86_seg_fs;
- goto push_seg;
-
- case X86EMUL_OPC(0x0f, 0xa1): /* pop %%fs */
- src.val = x86_seg_fs;
- goto pop_seg;
-
case X86EMUL_OPC(0x0f, 0xa2): /* cpuid */ {
unsigned int eax = _regs.eax, ebx = _regs.ebx;
unsigned int ecx = _regs.ecx, edx = _regs.edx;
@@ -5202,14 +5183,6 @@ x86_emulate(
break;
}
- case X86EMUL_OPC(0x0f, 0xa8): /* push %%gs */
- src.val = x86_seg_gs;
- goto push_seg;
-
- case X86EMUL_OPC(0x0f, 0xa9): /* pop %%gs */
- src.val = x86_seg_gs;
- goto pop_seg;
-
case X86EMUL_OPC(0x0f, 0xab): bts: /* bts */
emulate_2op_SrcV_nobyte("bts", src, dst, _regs.eflags);
break;
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