public inbox for kvm@vger.kernel.org
 help / color / mirror / Atom feed
* [PATCH] x86: fix mwait_play_dead() faulting on mwait-incapable cpus
       [not found] <201105301143.p4UBhco4001230@demeter2.kernel.org>
@ 2011-05-30 12:23 ` Avi Kivity
  2011-05-30 12:36   ` Török Edwin
  0 siblings, 1 reply; 2+ messages in thread
From: Avi Kivity @ 2011-05-30 12:23 UTC (permalink / raw)
  To: Ingo Molnar, H. Peter Anvin, Török Edwin
  Cc: kvm, Christoph Lameter, linux-kernel

A logic error in mwait_play_dead() causes the kernel to use mwait
even on cpus which don't support it, such as KVM virtual cpus.

Introduced by 349c004e3d31fd.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=36222

Reported-by: Török Edwin <edwintorok@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kernel/smpboot.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index eefd967..33a0c11 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1332,7 +1332,7 @@ static inline void mwait_play_dead(void)
 	void *mwait_ptr;
 	struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info);
 
-	if (!this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c))
+	if (!(this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c)))
 		return;
 	if (!this_cpu_has(X86_FEATURE_CLFLSH))
 		return;
-- 
1.7.5.3

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] x86: fix mwait_play_dead() faulting on mwait-incapable cpus
  2011-05-30 12:23 ` [PATCH] x86: fix mwait_play_dead() faulting on mwait-incapable cpus Avi Kivity
@ 2011-05-30 12:36   ` Török Edwin
  0 siblings, 0 replies; 2+ messages in thread
From: Török Edwin @ 2011-05-30 12:36 UTC (permalink / raw)
  To: Avi Kivity
  Cc: Ingo Molnar, H. Peter Anvin, kvm, Christoph Lameter, linux-kernel

On 05/30/2011 03:23 PM, Avi Kivity wrote:
> A logic error in mwait_play_dead() causes the kernel to use mwait
> even on cpus which don't support it, such as KVM virtual cpus.
> 
> Introduced by 349c004e3d31fd.
> 
> Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=36222

Confirmed that it fixes it.

>
> Reported-by: Török Edwin <edwintorok@gmail.com>
> Signed-off-by: Avi Kivity <avi@redhat.com>

You can add this if you want to:
Tested-by: Török Edwin <edwintorok@gmail.com>

Thanks,
--Edwin

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2011-05-30 12:36 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <201105301143.p4UBhco4001230@demeter2.kernel.org>
2011-05-30 12:23 ` [PATCH] x86: fix mwait_play_dead() faulting on mwait-incapable cpus Avi Kivity
2011-05-30 12:36   ` Török Edwin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox