* [PATCH] x86emul: properly refuse LOCK on most 0FC7 insns
@ 2017-09-22 9:02 Jan Beulich
2017-09-27 14:01 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2017-09-22 9:02 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper
When adding support for RDRAND/RDSEED/RDPID I didn't remember to also
update this special early check. Make it (hopefully) future-proof by
also refusing VEX-encodings.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -3087,7 +3087,9 @@ x86_emulate(
* The only implicit-operands instructions allowed a LOCK prefix are
* CMPXCHG{8,16}B (MOV CRn is being handled elsewhere).
*/
- generate_exception_if(lock_prefix && (ext != ext_0f || b != 0xc7),
+ generate_exception_if(lock_prefix &&
+ (vex.opcx || ext != ext_0f || b != 0xc7 ||
+ (modrm_reg & 7) != 1 || ea.type != OP_MEM),
EXC_UD);
dst.type = OP_NONE;
break;
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86emul: properly refuse LOCK on most 0FC7 insns
2017-09-22 9:02 [PATCH] x86emul: properly refuse LOCK on most 0FC7 insns Jan Beulich
@ 2017-09-27 14:01 ` Andrew Cooper
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cooper @ 2017-09-27 14:01 UTC (permalink / raw)
To: Jan Beulich, xen-devel
On 22/09/17 10:02, Jan Beulich wrote:
> When adding support for RDRAND/RDSEED/RDPID I didn't remember to also
> update this special early check. Make it (hopefully) future-proof by
> also refusing VEX-encodings.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
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2017-09-22 9:02 [PATCH] x86emul: properly refuse LOCK on most 0FC7 insns Jan Beulich
2017-09-27 14:01 ` Andrew Cooper
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