* [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable
@ 2017-04-13 2:20 Xuquan (Quan Xu)
2017-04-12 19:35 ` Chao Gao
0 siblings, 1 reply; 4+ messages in thread
From: Xuquan (Quan Xu) @ 2017-04-13 2:20 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper, Kevin Tian, Jun Nakajima, Jan Beulich, Chao Gao
[-- Attachment #1: Type: text/plain, Size: 1032 bytes --]
>From 946e7589e5a875574c7567a91943d47c38218a6f Mon Sep 17 00:00:00 2001
From: Quan Xu <xuquan8@huawei.com>
Date: Fri, 14 Apr 2017 02:11:30 +0800
Subject: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked
to runnable
set 'SN' bit of posted-interrupt descriptor when the runstate transition
is from blocked to runnable (SN bit of posted-interrupt descriptor is still
set to a blocked vCPU), otherwise PI notification event may be sent to a
non-running vCPU.
Signed-off-by: Quan Xu <xuquan8@huawei.com>
---
xen/arch/x86/hvm/vmx/vmx.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 9c5a388..956f104 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -142,9 +142,6 @@ static void vmx_pi_switch_from(struct vcpu *v)
{
struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
- if ( test_bit(_VPF_blocked, &v->pause_flags) )
- return;
-
pi_set_sn(pi_desc);
}
--
1.8.3.1
[-- Attachment #2: 0001-vmx-set-SN-bit-for-the-runstate-transition-from-bloc.patch --]
[-- Type: application/octet-stream, Size: 1003 bytes --]
From 946e7589e5a875574c7567a91943d47c38218a6f Mon Sep 17 00:00:00 2001
From: Quan Xu <xuquan8@huawei.com>
Date: Fri, 14 Apr 2017 02:11:30 +0800
Subject: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked
to runnable
set 'SN' bit of posted-interrupt descriptor when the runstate transition
is from blocked to runnable (SN bit of posted-interrupt descriptor is still
set to a blocked vCPU), otherwise PI notification event may be sent to a
non-running vCPU.
Signed-off-by: Quan Xu <xuquan8@huawei.com>
---
xen/arch/x86/hvm/vmx/vmx.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 9c5a388..956f104 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -142,9 +142,6 @@ static void vmx_pi_switch_from(struct vcpu *v)
{
struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
- if ( test_bit(_VPF_blocked, &v->pause_flags) )
- return;
-
pi_set_sn(pi_desc);
}
--
1.8.3.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable
2017-04-13 2:20 [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable Xuquan (Quan Xu)
@ 2017-04-12 19:35 ` Chao Gao
2017-04-13 3:44 ` Xuquan (Quan Xu)
2017-04-13 12:35 ` Xuquan (Quan Xu)
0 siblings, 2 replies; 4+ messages in thread
From: Chao Gao @ 2017-04-12 19:35 UTC (permalink / raw)
To: Xuquan (Quan Xu)
Cc: Andrew Cooper, Kevin Tian, Jan Beulich, Jun Nakajima, xen-devel
On Thu, Apr 13, 2017 at 02:20:23AM +0000, Xuquan (Quan Xu) wrote:
>From 946e7589e5a875574c7567a91943d47c38218a6f Mon Sep 17 00:00:00 2001
>From: Quan Xu <xuquan8@huawei.com>
>Date: Fri, 14 Apr 2017 02:11:30 +0800
>Subject: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked
> to runnable
>
>set 'SN' bit of posted-interrupt descriptor when the runstate transition
>is from blocked to runnable (SN bit of posted-interrupt descriptor is still
>set to a blocked vCPU), otherwise PI notification event may be sent to a
Currently, we clear 'SN' bit for a blocked vCPU in order to receive a wakeup
interrupt to wake up the blocked vCPU. Also note that wakeup interrupt is not
a special vector for CPU.
>non-running vCPU.
>
>Signed-off-by: Quan Xu <xuquan8@huawei.com>
>---
> xen/arch/x86/hvm/vmx/vmx.c | 3 ---
> 1 file changed, 3 deletions(-)
>
>diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
>index 9c5a388..956f104 100644
>--- a/xen/arch/x86/hvm/vmx/vmx.c
>+++ b/xen/arch/x86/hvm/vmx/vmx.c
>@@ -142,9 +142,6 @@ static void vmx_pi_switch_from(struct vcpu *v)
> {
> struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
>
>- if ( test_bit(_VPF_blocked, &v->pause_flags) )
>- return;
>-
I wander whether vmx_pi_switch_from() will be called in the transition
blocked -> runnable.
In my mind, the function is called during context switch and consumes
the vcpu that is to be blocked or runnable. I think this if() statement
is to distinguish 'block' case and doesn't set 'SN' for this case.
Thanks
Chao
> pi_set_sn(pi_desc);
> }
>
>--
>1.8.3.1
>_______________________________________________
>Xen-devel mailing list
>Xen-devel@lists.xen.org
>https://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable
2017-04-12 19:35 ` Chao Gao
@ 2017-04-13 3:44 ` Xuquan (Quan Xu)
2017-04-13 12:35 ` Xuquan (Quan Xu)
1 sibling, 0 replies; 4+ messages in thread
From: Xuquan (Quan Xu) @ 2017-04-13 3:44 UTC (permalink / raw)
To: Chao Gao; +Cc: Andrew Cooper, Kevin Tian, Jan Beulich, Jun Nakajima, xen-devel
On April 13, 2017 3:35 AM, Chao Gao wrote:
>On Thu, Apr 13, 2017 at 02:20:23AM +0000, Xuquan (Quan Xu) wrote:
>>From 946e7589e5a875574c7567a91943d47c38218a6f Mon Sep 17
>00:00:00 2001
>>From: Quan Xu <xuquan8@huawei.com>
>>Date: Fri, 14 Apr 2017 02:11:30 +0800
>>Subject: [PATCH v1] vmx: set 'SN' bit for the runstate transition from
>>blocked to runnable
>>
>>set 'SN' bit of posted-interrupt descriptor when the runstate
>>transition is from blocked to runnable (SN bit of posted-interrupt
>>descriptor is still set to a blocked vCPU), otherwise PI notification
>>event may be sent to a
>
>Currently, we clear 'SN' bit for a blocked vCPU in order to receive a wakeup
>interrupt to wake up the blocked vCPU. Also note that wakeup interrupt is not
>a special vector for CPU.
>
Sorry, a typo 's/set/clear/'....
You are right. It is clear. that's why I want to set it.
>>non-running vCPU.
>>
>>Signed-off-by: Quan Xu <xuquan8@huawei.com>
>>---
>> xen/arch/x86/hvm/vmx/vmx.c | 3 ---
>> 1 file changed, 3 deletions(-)
>>
>>diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
>>index 9c5a388..956f104 100644
>>--- a/xen/arch/x86/hvm/vmx/vmx.c
>>+++ b/xen/arch/x86/hvm/vmx/vmx.c
>>@@ -142,9 +142,6 @@ static void vmx_pi_switch_from(struct vcpu *v) {
>> struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
>>
>>- if ( test_bit(_VPF_blocked, &v->pause_flags) )
>>- return;
>>-
>
>I wander whether vmx_pi_switch_from() will be called in the transition
>blocked -> runnable.
>In my mind, the function is called during context switch and consumes the
>vcpu that is to be blocked or runnable.
If you are right, my patch is wrong..
Chao, thank you. I will check it again..
Quan
>I think this if() statement is to
>distinguish 'block' case and doesn't set 'SN' for this case.
>
>Thanks
>Chao
>
>> pi_set_sn(pi_desc);
>> }
>>
>>--
>>1.8.3.1
>
>
>>_______________________________________________
>>Xen-devel mailing list
>>Xen-devel@lists.xen.org
>>https://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable
2017-04-12 19:35 ` Chao Gao
2017-04-13 3:44 ` Xuquan (Quan Xu)
@ 2017-04-13 12:35 ` Xuquan (Quan Xu)
1 sibling, 0 replies; 4+ messages in thread
From: Xuquan (Quan Xu) @ 2017-04-13 12:35 UTC (permalink / raw)
To: Xuquan (Quan Xu), Chao Gao
Cc: Andrew Cooper, Kevin Tian, Jan Beulich, Jun Nakajima, xen-devel
__sorry for the noise, please ignore this patch__
On April 13, 2017 11:45 AM, Quan Xu wrote:
>On April 13, 2017 3:35 AM, Chao Gao wrote:
>>On Thu, Apr 13, 2017 at 02:20:23AM +0000, Xuquan (Quan Xu) wrote:
>>>From 946e7589e5a875574c7567a91943d47c38218a6f Mon Sep 17
>>00:00:00 2001
>>>From: Quan Xu <xuquan8@huawei.com>
>>>Date: Fri, 14 Apr 2017 02:11:30 +0800
>>>Subject: [PATCH v1] vmx: set 'SN' bit for the runstate transition from
>>>blocked to runnable
>>>
>>>set 'SN' bit of posted-interrupt descriptor when the runstate
>>>transition is from blocked to runnable (SN bit of posted-interrupt
>>>descriptor is still set to a blocked vCPU), otherwise PI notification
>>>event may be sent to a
>>
>>Currently, we clear 'SN' bit for a blocked vCPU in order to receive a
>>wakeup interrupt to wake up the blocked vCPU. Also note that wakeup
>>interrupt is not a special vector for CPU.
>>
>Sorry, a typo 's/set/clear/'....
>You are right. It is clear. that's why I want to set it.
>
>
>>>non-running vCPU.
>>>
>>>Signed-off-by: Quan Xu <xuquan8@huawei.com>
>>>---
>>> xen/arch/x86/hvm/vmx/vmx.c | 3 ---
>>> 1 file changed, 3 deletions(-)
>>>
>>>diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
>>>index 9c5a388..956f104 100644
>>>--- a/xen/arch/x86/hvm/vmx/vmx.c
>>>+++ b/xen/arch/x86/hvm/vmx/vmx.c
>>>@@ -142,9 +142,6 @@ static void vmx_pi_switch_from(struct vcpu *v) {
>>> struct pi_desc *pi_desc = &v->arch.hvm_vmx.pi_desc;
>>>
>>>- if ( test_bit(_VPF_blocked, &v->pause_flags) )
>>>- return;
>>>-
>>
>>I wander whether vmx_pi_switch_from() will be called in the transition
>>blocked -> runnable.
>>In my mind, the function is called during context switch and consumes
>>the vcpu that is to be blocked or runnable.
>
>If you are right, my patch is wrong..
>
>Chao, thank you. I will check it again..
Chao, checked the code, I think you are right..
For example, HLT:
vmx_vmexit_handler(... case EXIT_REASON_HLT ... )
|
hvm_hlt()
|
do_sched_op(... SCHEDOP_block ...)
|
vcpu_block_enable_events()
|
vcpu_block()
|
arch_vcpu_block()
raise_softirq(SCHEDULE_SOFTIRQ)
if the vcpu is blocked, the vcpu is de-scheduled.. sorry for the noise, please ignore this patch ..
Quan
>
>Quan
>
>>I think this if() statement is to
>>distinguish 'block' case and doesn't set 'SN' for this case.
>>
>
>
>
>
>
>>Thanks
>>Chao
>>
>>> pi_set_sn(pi_desc);
>>> }
>>>
>>>--
>>>1.8.3.1
>>
>>
>>>_______________________________________________
>>>Xen-devel mailing list
>>>Xen-devel@lists.xen.org
>>>https://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-04-13 2:20 [PATCH v1] vmx: set 'SN' bit for the runstate transition from blocked to runnable Xuquan (Quan Xu)
2017-04-12 19:35 ` Chao Gao
2017-04-13 3:44 ` Xuquan (Quan Xu)
2017-04-13 12:35 ` Xuquan (Quan Xu)
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