From: "Jan Beulich" <JBeulich@suse.com>
To: xen-devel <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wei.liu2@citrix.com>
Subject: [PATCH] x86emul: CMOVcc always writes its destination
Date: Wed, 23 Nov 2016 04:24:38 -0700 [thread overview]
Message-ID: <58358A8602000078001213DD@prv-mh.provo.novell.com> (raw)
[-- 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 --]
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next reply other threads:[~2016-11-23 11:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 11:24 Jan Beulich [this message]
2016-11-25 10:31 ` [PATCH] x86emul: CMOVcc always writes its destination Andrew Cooper
2016-11-25 13:08 ` Wei Liu
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