The diag 318 data contains values that denote information regarding the
guest's environment. Currently, it is unecessarily difficult to observe
this value (either manually-inserted debug statements, gdb stepping, mem
dumping etc). It's useful to observe this information to obtain an
at-a-glance view of the guest's environment, so lets add a simple VCPU
event that prints the CPNC to the s390dbf logs.
Signed-off-by: Collin Walling <[email protected]>
---
arch/s390/kvm/kvm-s390.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 6a6dd5e1daf6..da3ff24eabd0 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
+ VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
}
/*
* If userspace sets the riccb (e.g. after migration) to a valid state,
--
2.31.1
Am 27.10.21 um 04:54 schrieb Collin Walling:
> The diag 318 data contains values that denote information regarding the
> guest's environment. Currently, it is unecessarily difficult to observe
> this value (either manually-inserted debug statements, gdb stepping, mem
> dumping etc). It's useful to observe this information to obtain an
> at-a-glance view of the guest's environment, so lets add a simple VCPU
> event that prints the CPNC to the s390dbf logs.
>
> Signed-off-by: Collin Walling <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
And it even finds a bug in QEMU. We clear the CPNC on local CPU resets.
Can you have a look? I think we just have to move the cpnc in the env
field from the normal/initial reset range to the full reset range.
> ---
> arch/s390/kvm/kvm-s390.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 6a6dd5e1daf6..da3ff24eabd0 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
> }
> /*
> * If userspace sets the riccb (e.g. after migration) to a valid state,
>
Am 27.10.21 um 04:54 schrieb Collin Walling:
> The diag 318 data contains values that denote information regarding the
> guest's environment. Currently, it is unecessarily difficult to observe
> this value (either manually-inserted debug statements, gdb stepping, mem
> dumping etc). It's useful to observe this information to obtain an
> at-a-glance view of the guest's environment, so lets add a simple VCPU
> event that prints the CPNC to the s390dbf logs.
>
> Signed-off-by: Collin Walling <[email protected]>
applied and queued
> ---
> arch/s390/kvm/kvm-s390.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 6a6dd5e1daf6..da3ff24eabd0 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
After comparing this with the other events I think level==3 is better. Changed when applying.
> }
> /*
> * If userspace sets the riccb (e.g. after migration) to a valid state,
>
On 10/27/21 01:37, Christian Borntraeger wrote:
> Am 27.10.21 um 04:54 schrieb Collin Walling:
>> The diag 318 data contains values that denote information regarding the
>> guest's environment. Currently, it is unecessarily difficult to observe
>> this value (either manually-inserted debug statements, gdb stepping, mem
>> dumping etc). It's useful to observe this information to obtain an
>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>> event that prints the CPNC to the s390dbf logs.
>>
>> Signed-off-by: Collin Walling <[email protected]>
>
> Acked-by: Christian Borntraeger <[email protected]>
>
> And it even finds a bug in QEMU. We clear the CPNC on local CPU resets.
> Can you have a look? I think we just have to move the cpnc in the env
> field from the normal/initial reset range to the full reset range.
I'll take a look at this right away.
>> ---
>> arch/s390/kvm/kvm-s390.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d",
>> vcpu->arch.diag318_info.cpnc);
>> }
>> /*
>> * If userspace sets the riccb (e.g. after migration) to a valid
>> state,
>>
--
Regards,
Collin
Stay safe and stay healthy
On 10/27/21 01:41, Christian Borntraeger wrote:
> Am 27.10.21 um 04:54 schrieb Collin Walling:
>> The diag 318 data contains values that denote information regarding the
>> guest's environment. Currently, it is unecessarily difficult to observe
>> this value (either manually-inserted debug statements, gdb stepping, mem
>> dumping etc). It's useful to observe this information to obtain an
>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>> event that prints the CPNC to the s390dbf logs.
>>
>> Signed-off-by: Collin Walling <[email protected]>
>
> applied and queued
>> ---
>> arch/s390/kvm/kvm-s390.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d",
>> vcpu->arch.diag318_info.cpnc);
>
> After comparing this with the other events I think level==3 is better.
> Changed when applying.
>> }
>> /*
>> * If userspace sets the riccb (e.g. after migration) to a valid
>> state,
>>
Thanks!
--
Regards,
Collin
Stay safe and stay healthy
Am 08.11.21 um 12:12 schrieb Janosch Frank:
> On 10/27/21 04:54, Collin Walling wrote:
>> The diag 318 data contains values that denote information regarding the
>> guest's environment. Currently, it is unecessarily difficult to observe
>> this value (either manually-inserted debug statements, gdb stepping, mem
>> dumping etc). It's useful to observe this information to obtain an
>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>> event that prints the CPNC to the s390dbf logs.
>>
>> Signed-off-by: Collin Walling <[email protected]>
>> ---
>> arch/s390/kvm/kvm-s390.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
>> }
>> /*
>> * If userspace sets the riccb (e.g. after migration) to a valid state,
>>
>
> Won't that turn up for every vcpu and spam the log?
only if the userspace always sets the dirty bit (which it should not).
On 10/27/21 04:54, Collin Walling wrote:
> The diag 318 data contains values that denote information regarding the
> guest's environment. Currently, it is unecessarily difficult to observe
> this value (either manually-inserted debug statements, gdb stepping, mem
> dumping etc). It's useful to observe this information to obtain an
> at-a-glance view of the guest's environment, so lets add a simple VCPU
> event that prints the CPNC to the s390dbf logs.
>
> Signed-off-by: Collin Walling <[email protected]>
> ---
> arch/s390/kvm/kvm-s390.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 6a6dd5e1daf6..da3ff24eabd0 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
> }
> /*
> * If userspace sets the riccb (e.g. after migration) to a valid state,
>
Won't that turn up for every vcpu and spam the log?
Am 08.11.21 um 13:48 schrieb Janosch Frank:
> On 11/8/21 13:04, Christian Borntraeger wrote:
>>
>>
>> Am 08.11.21 um 12:12 schrieb Janosch Frank:
>>> On 10/27/21 04:54, Collin Walling wrote:
>>>> The diag 318 data contains values that denote information regarding the
>>>> guest's environment. Currently, it is unecessarily difficult to observe
>>>> this value (either manually-inserted debug statements, gdb stepping, mem
>>>> dumping etc). It's useful to observe this information to obtain an
>>>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>>>> event that prints the CPNC to the s390dbf logs.
>>>>
>>>> Signed-off-by: Collin Walling <[email protected]>
>>>> ---
>>>> arch/s390/kvm/kvm-s390.c | 1 +
>>>> 1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>>>> --- a/arch/s390/kvm/kvm-s390.c
>>>> +++ b/arch/s390/kvm/kvm-s390.c
>>>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>>>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>>>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>>>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>>>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
>>>> }
>>>> /*
>>>> * If userspace sets the riccb (e.g. after migration) to a valid state,
>>>>
>>>
>>> Won't that turn up for every vcpu and spam the log?
>>
>> only if the userspace always sets the dirty bit (which it should not).
>>
>
> But that's exactly what it does, no?
> We do a loop over all vcpus and call kvm_s390_set_diag318() which sets the info in kvm_run and sets the diag318 bit in the kvm_dirty_regs.
Yes, ONCE per CPU. And this is exactly what I want to see. (and it did show a bug in qemu that we only set it for one cpu to the correct value).
>
> @Collin: Could you check that please?
On 11/8/21 13:04, Christian Borntraeger wrote:
>
>
> Am 08.11.21 um 12:12 schrieb Janosch Frank:
>> On 10/27/21 04:54, Collin Walling wrote:
>>> The diag 318 data contains values that denote information regarding the
>>> guest's environment. Currently, it is unecessarily difficult to observe
>>> this value (either manually-inserted debug statements, gdb stepping, mem
>>> dumping etc). It's useful to observe this information to obtain an
>>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>>> event that prints the CPNC to the s390dbf logs.
>>>
>>> Signed-off-by: Collin Walling <[email protected]>
>>> ---
>>> arch/s390/kvm/kvm-s390.c | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>>> --- a/arch/s390/kvm/kvm-s390.c
>>> +++ b/arch/s390/kvm/kvm-s390.c
>>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
>>> }
>>> /*
>>> * If userspace sets the riccb (e.g. after migration) to a valid state,
>>>
>>
>> Won't that turn up for every vcpu and spam the log?
>
> only if the userspace always sets the dirty bit (which it should not).
>
But that's exactly what it does, no?
We do a loop over all vcpus and call kvm_s390_set_diag318() which sets
the info in kvm_run and sets the diag318 bit in the kvm_dirty_regs.
@Collin: Could you check that please?
On 11/8/21 13:50, Christian Borntraeger wrote:
>
>
> Am 08.11.21 um 13:48 schrieb Janosch Frank:
>> On 11/8/21 13:04, Christian Borntraeger wrote:
>>>
>>>
>>> Am 08.11.21 um 12:12 schrieb Janosch Frank:
>>>> On 10/27/21 04:54, Collin Walling wrote:
>>>>> The diag 318 data contains values that denote information regarding the
>>>>> guest's environment. Currently, it is unecessarily difficult to observe
>>>>> this value (either manually-inserted debug statements, gdb stepping, mem
>>>>> dumping etc). It's useful to observe this information to obtain an
>>>>> at-a-glance view of the guest's environment, so lets add a simple VCPU
>>>>> event that prints the CPNC to the s390dbf logs.
>>>>>
>>>>> Signed-off-by: Collin Walling <[email protected]>
>>>>> ---
>>>>> arch/s390/kvm/kvm-s390.c | 1 +
>>>>> 1 file changed, 1 insertion(+)
>>>>>
>>>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>>>> index 6a6dd5e1daf6..da3ff24eabd0 100644
>>>>> --- a/arch/s390/kvm/kvm-s390.c
>>>>> +++ b/arch/s390/kvm/kvm-s390.c
>>>>> @@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
>>>>> if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
>>>>> vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
>>>>> vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
>>>>> + VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
>>>>> }
>>>>> /*
>>>>> * If userspace sets the riccb (e.g. after migration) to a valid state,
>>>>>
>>>>
>>>> Won't that turn up for every vcpu and spam the log?
>>>
>>> only if the userspace always sets the dirty bit (which it should not).
>>>
>>
>> But that's exactly what it does, no?
>> We do a loop over all vcpus and call kvm_s390_set_diag318() which sets the info in kvm_run and sets the diag318 bit in the kvm_dirty_regs.
>
> Yes, ONCE per CPU. And this is exactly what I want to see. (and it did show a bug in qemu that we only set it for one cpu to the correct value).
Ok.
I didn't really want to have n entries in the log hence I asked.
318 is a bit weird as it's a per VM value we need to put into all sie
blocks.
>
>>
>> @Collin: Could you check that please?