* [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock
@ 2016-01-26 16:15 Paolo Bonzini
2016-01-26 16:21 ` Michael S. Tsirkin
0 siblings, 1 reply; 5+ messages in thread
From: Paolo Bonzini @ 2016-01-26 16:15 UTC (permalink / raw)
To: qemu-devel; +Cc: cminyard, mst
This is not necessary and actually causes a hang; it was probably copied
and pasted from KVM code, that is one of the very few places that run
outside iothread lock.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/ipmi/ipmi.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
index 52aba1e..fcba0ca 100644
--- a/hw/ipmi/ipmi.c
+++ b/hw/ipmi/ipmi.c
@@ -50,9 +50,7 @@ static int ipmi_do_hw_op(IPMIInterface *s, enum ipmi_op op, int checkonly)
if (checkonly) {
return 0;
}
- qemu_mutex_lock_iothread();
qmp_inject_nmi(NULL);
- qemu_mutex_unlock_iothread();
return 0;
case IPMI_POWERCYCLE_CHASSIS:
--
2.5.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock
2016-01-26 16:15 [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock Paolo Bonzini
@ 2016-01-26 16:21 ` Michael S. Tsirkin
2016-01-26 17:57 ` Corey Minyard
0 siblings, 1 reply; 5+ messages in thread
From: Michael S. Tsirkin @ 2016-01-26 16:21 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: cminyard, qemu-devel
On Tue, Jan 26, 2016 at 05:15:53PM +0100, Paolo Bonzini wrote:
> This is not necessary and actually causes a hang; it was probably copied
> and pasted from KVM code, that is one of the very few places that run
> outside iothread lock.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Makes sense. I wonder how hard would it be to have a test to catch this.
> ---
> hw/ipmi/ipmi.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
> index 52aba1e..fcba0ca 100644
> --- a/hw/ipmi/ipmi.c
> +++ b/hw/ipmi/ipmi.c
> @@ -50,9 +50,7 @@ static int ipmi_do_hw_op(IPMIInterface *s, enum ipmi_op op, int checkonly)
> if (checkonly) {
> return 0;
> }
> - qemu_mutex_lock_iothread();
> qmp_inject_nmi(NULL);
> - qemu_mutex_unlock_iothread();
> return 0;
>
> case IPMI_POWERCYCLE_CHASSIS:
> --
> 2.5.0
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock
2016-01-26 16:21 ` Michael S. Tsirkin
@ 2016-01-26 17:57 ` Corey Minyard
2016-01-26 18:00 ` Paolo Bonzini
0 siblings, 1 reply; 5+ messages in thread
From: Corey Minyard @ 2016-01-26 17:57 UTC (permalink / raw)
To: Michael S. Tsirkin, Paolo Bonzini; +Cc: qemu-devel
On 01/26/2016 10:21 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 26, 2016 at 05:15:53PM +0100, Paolo Bonzini wrote:
>> This is not necessary and actually causes a hang; it was probably copied
>> and pasted from KVM code, that is one of the very few places that run
>> outside iothread lock.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Makes sense. I wonder how hard would it be to have a test to catch this.
The IPMI side would be easy for me, but I don't know how to handle
catching the NMI.
-corey
>> ---
>> hw/ipmi/ipmi.c | 2 --
>> 1 file changed, 2 deletions(-)
>>
>> diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
>> index 52aba1e..fcba0ca 100644
>> --- a/hw/ipmi/ipmi.c
>> +++ b/hw/ipmi/ipmi.c
>> @@ -50,9 +50,7 @@ static int ipmi_do_hw_op(IPMIInterface *s, enum ipmi_op op, int checkonly)
>> if (checkonly) {
>> return 0;
>> }
>> - qemu_mutex_lock_iothread();
>> qmp_inject_nmi(NULL);
>> - qemu_mutex_unlock_iothread();
>> return 0;
>>
>> case IPMI_POWERCYCLE_CHASSIS:
>> --
>> 2.5.0
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock
2016-01-26 17:57 ` Corey Minyard
@ 2016-01-26 18:00 ` Paolo Bonzini
0 siblings, 0 replies; 5+ messages in thread
From: Paolo Bonzini @ 2016-01-26 18:00 UTC (permalink / raw)
To: Corey Minyard, Michael S. Tsirkin; +Cc: qemu-devel
On 26/01/2016 18:57, Corey Minyard wrote:
> On 01/26/2016 10:21 AM, Michael S. Tsirkin wrote:
>> On Tue, Jan 26, 2016 at 05:15:53PM +0100, Paolo Bonzini wrote:
>>> This is not necessary and actually causes a hang; it was probably copied
>>> and pasted from KVM code, that is one of the very few places that run
>>> outside iothread lock.
>>>
>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> Makes sense. I wonder how hard would it be to have a test to catch this.
>
> The IPMI side would be easy for me, but I don't know how to handle
> catching the NMI.
I'm afraid there's no way to trap an NMI from qtest.
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock
@ 2016-01-26 16:59 Paolo Bonzini
0 siblings, 0 replies; 5+ messages in thread
From: Paolo Bonzini @ 2016-01-26 16:59 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha
This is not necessary and actually causes a hang; it was probably copied
and pasted from KVM code, that is one of the very few places that run
outside iothread lock.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/ipmi/ipmi.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
index 52aba1e..fcba0ca 100644
--- a/hw/ipmi/ipmi.c
+++ b/hw/ipmi/ipmi.c
@@ -50,9 +50,7 @@ static int ipmi_do_hw_op(IPMIInterface *s, enum ipmi_op op, int checkonly)
if (checkonly) {
return 0;
}
- qemu_mutex_lock_iothread();
qmp_inject_nmi(NULL);
- qemu_mutex_unlock_iothread();
return 0;
case IPMI_POWERCYCLE_CHASSIS:
--
2.5.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-01-26 18:00 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2016-01-26 16:15 [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock Paolo Bonzini
2016-01-26 16:21 ` Michael S. Tsirkin
2016-01-26 17:57 ` Corey Minyard
2016-01-26 18:00 ` Paolo Bonzini
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2016-01-26 16:59 Paolo Bonzini
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