* [PATCH] x86emul: CMOVcc always writes its destination
@ 2016-11-23 11:24 Jan Beulich
2016-11-25 10:31 ` Andrew Cooper
0 siblings, 1 reply; 3+ messages in thread
From: Jan Beulich @ 2016-11-23 11:24 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Wei Liu
[-- Attachment #1: Type: text/plain, Size: 1516 bytes --]
This would be benign if there wasn't the zero-extending side effect of
32-bit operations in 64-bit mode.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/tools/tests/x86_emulator/test_x86_emulator.c
+++ b/tools/tests/x86_emulator/test_x86_emulator.c
@@ -653,6 +653,21 @@ int main(int argc, char **argv)
printf("okay\n");
#else
printf("skipped\n");
+
+ printf("%-40s", "Testing cmovz %ecx,%eax...");
+ instr[0] = 0x0f; instr[1] = 0x44; instr[2] = 0xc1;
+ regs.eflags = 0x200;
+ regs.eip = (unsigned long)&instr[0];
+ regs.rax = 0x1111111122222222;
+ regs.rcx = 0x3333333344444444;
+ rc = x86_emulate(&ctxt, &emulops);
+ if ( (rc != X86EMUL_OKAY) ||
+ (regs.rax != 0x0000000022222222) ||
+ (regs.rcx != 0x3333333344444444) ||
+ (regs.eflags != 0x200) ||
+ (regs.eip != (unsigned long)&instr[3]) )
+ goto fail;
+ printf("okay\n");
#endif
printf("%-40s", "Testing movbe (%%ecx),%%eax...");
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -4784,9 +4784,8 @@ x86_emulate(
case X86EMUL_OPC(0x0f, 0x40) ... X86EMUL_OPC(0x0f, 0x4f): /* cmovcc */
vcpu_must_have_cmov();
- dst.val = src.val;
- if ( !test_cc(b, _regs.eflags) )
- dst.type = OP_NONE;
+ if ( test_cc(b, _regs.eflags) )
+ dst.val = src.val;
break;
case X86EMUL_OPC(0x0f, 0x34): /* sysenter */ {
[-- Attachment #2: x86emul-CMOV-dest.patch --]
[-- Type: text/plain, Size: 1559 bytes --]
x86emul: CMOVcc always writes its destination
This would be benign if there wasn't the zero-extending side effect of
32-bit operations in 64-bit mode.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/tools/tests/x86_emulator/test_x86_emulator.c
+++ b/tools/tests/x86_emulator/test_x86_emulator.c
@@ -653,6 +653,21 @@ int main(int argc, char **argv)
printf("okay\n");
#else
printf("skipped\n");
+
+ printf("%-40s", "Testing cmovz %ecx,%eax...");
+ instr[0] = 0x0f; instr[1] = 0x44; instr[2] = 0xc1;
+ regs.eflags = 0x200;
+ regs.eip = (unsigned long)&instr[0];
+ regs.rax = 0x1111111122222222;
+ regs.rcx = 0x3333333344444444;
+ rc = x86_emulate(&ctxt, &emulops);
+ if ( (rc != X86EMUL_OKAY) ||
+ (regs.rax != 0x0000000022222222) ||
+ (regs.rcx != 0x3333333344444444) ||
+ (regs.eflags != 0x200) ||
+ (regs.eip != (unsigned long)&instr[3]) )
+ goto fail;
+ printf("okay\n");
#endif
printf("%-40s", "Testing movbe (%%ecx),%%eax...");
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -4784,9 +4784,8 @@ x86_emulate(
case X86EMUL_OPC(0x0f, 0x40) ... X86EMUL_OPC(0x0f, 0x4f): /* cmovcc */
vcpu_must_have_cmov();
- dst.val = src.val;
- if ( !test_cc(b, _regs.eflags) )
- dst.type = OP_NONE;
+ if ( test_cc(b, _regs.eflags) )
+ dst.val = src.val;
break;
case X86EMUL_OPC(0x0f, 0x34): /* sysenter */ {
[-- Attachment #3: Type: text/plain, Size: 127 bytes --]
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86emul: CMOVcc always writes its destination
2016-11-23 11:24 [PATCH] x86emul: CMOVcc always writes its destination Jan Beulich
@ 2016-11-25 10:31 ` Andrew Cooper
2016-11-25 13:08 ` Wei Liu
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Cooper @ 2016-11-25 10:31 UTC (permalink / raw)
To: Jan Beulich, xen-devel; +Cc: Wei Liu
On 23/11/16 11:24, Jan Beulich wrote:
> This would be benign if there wasn't the zero-extending side effect of
> 32-bit operations in 64-bit mode.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] x86emul: CMOVcc always writes its destination
2016-11-25 10:31 ` Andrew Cooper
@ 2016-11-25 13:08 ` Wei Liu
0 siblings, 0 replies; 3+ messages in thread
From: Wei Liu @ 2016-11-25 13:08 UTC (permalink / raw)
To: Andrew Cooper; +Cc: xen-devel, Wei Liu, Jan Beulich
On Fri, Nov 25, 2016 at 10:31:55AM +0000, Andrew Cooper wrote:
> On 23/11/16 11:24, Jan Beulich wrote:
> > This would be benign if there wasn't the zero-extending side effect of
> > 32-bit operations in 64-bit mode.
> >
> > Signed-off-by: Jan Beulich <jbeulich@suse.com>
>
> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-11-25 13:08 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-11-23 11:24 [PATCH] x86emul: CMOVcc always writes its destination Jan Beulich
2016-11-25 10:31 ` Andrew Cooper
2016-11-25 13:08 ` Wei Liu
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.