[PATCH v1] s390x/kvm: Set default cpu model for all machine classes

David Hildenbrand posted 1 patch 6 years ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20191021093456.6168-1-david@redhat.com
Maintainers: David Hildenbrand <david@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Halil Pasic <pasic@linux.ibm.com>, Richard Henderson <rth@twiddle.net>, Christian Borntraeger <borntraeger@de.ibm.com>
There is a newer version of this series
target/s390x/kvm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
[PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by David Hildenbrand 6 years ago
We have to set the default model of all machine classes, not just for
the active one. Otherwise, "query-machines" will indicate the wrong
CPU model ("qemu-s390x-cpu" instead of "host-s390x-cpu") as
"default-cpu-type".

Doing a
    {"execute":"query-machines"}
under KVM now results in
    {"return": [
        {
            "hotpluggable-cpus": true,
            "name": "s390-ccw-virtio-4.0",
            "numa-mem-supported": false,
            "default-cpu-type": "host-s390x-cpu",
            "cpu-max": 248,
            "deprecated": false},
        {
            "hotpluggable-cpus": true,
            "name": "s390-ccw-virtio-2.7",
            "numa-mem-supported": false,
            "default-cpu-type": "host-s390x-cpu",
            "cpu-max": 248,
            "deprecated": false
        } ...

Reported-by: Jiri Denemark <jdenemar@redhat.com>
Fixes: b6805e127c6b ("s390x: use generic cpu_model parsing")
Cc: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/kvm.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index c24c869e77..5966ab0d37 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -320,11 +320,17 @@ void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp)
     cap_hpage_1m = 1;
 }
 
-int kvm_arch_init(MachineState *ms, KVMState *s)
+static void ccw_machine_class_foreach(ObjectClass *klass, void *opaque)
 {
-    MachineClass *mc = MACHINE_GET_CLASS(ms);
+    MachineClass *mc = MACHINE_CLASS(klass);
 
     mc->default_cpu_type = S390_CPU_TYPE_NAME("host");
+}
+
+int kvm_arch_init(MachineState *ms, KVMState *s)
+{
+    object_class_foreach(ccw_machine_class_foreach, TYPE_S390_CCW_MACHINE,
+                         false, NULL);
 
     if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
         error_report("KVM is missing capability KVM_CAP_DEVICE_CTRL - "
-- 
2.21.0


Re: [PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by Thomas Huth 6 years ago
On 21/10/2019 11.34, David Hildenbrand wrote:
> We have to set the default model of all machine classes, not just for
> the active one. Otherwise, "query-machines" will indicate the wrong
> CPU model ("qemu-s390x-cpu" instead of "host-s390x-cpu") as
> "default-cpu-type".
> 
> Doing a
>     {"execute":"query-machines"}
> under KVM now results in
>     {"return": [
>         {
>             "hotpluggable-cpus": true,
>             "name": "s390-ccw-virtio-4.0",
>             "numa-mem-supported": false,
>             "default-cpu-type": "host-s390x-cpu",
>             "cpu-max": 248,
>             "deprecated": false},
>         {
>             "hotpluggable-cpus": true,
>             "name": "s390-ccw-virtio-2.7",
>             "numa-mem-supported": false,
>             "default-cpu-type": "host-s390x-cpu",
>             "cpu-max": 248,
>             "deprecated": false
>         } ...
> 
> Reported-by: Jiri Denemark <jdenemar@redhat.com>
> Fixes: b6805e127c6b ("s390x: use generic cpu_model parsing")
> Cc: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/kvm.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index c24c869e77..5966ab0d37 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -320,11 +320,17 @@ void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp)
>      cap_hpage_1m = 1;
>  }
>  
> -int kvm_arch_init(MachineState *ms, KVMState *s)
> +static void ccw_machine_class_foreach(ObjectClass *klass, void *opaque)
>  {
> -    MachineClass *mc = MACHINE_GET_CLASS(ms);
> +    MachineClass *mc = MACHINE_CLASS(klass);

I think we rather wanted to avoid using "klass" in new code... maybe use
"oc" instead of "klass" ?

>      mc->default_cpu_type = S390_CPU_TYPE_NAME("host");
> +}
> +
> +int kvm_arch_init(MachineState *ms, KVMState *s)
> +{
> +    object_class_foreach(ccw_machine_class_foreach, TYPE_S390_CCW_MACHINE,
> +                         false, NULL);
>  
>      if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
>          error_report("KVM is missing capability KVM_CAP_DEVICE_CTRL - "
> 

Weird, if you start an older machine, you still get the "host" CPU
without your patch, too:

echo -e "info qom-tree \n quit" | \
 qemu-system-s390x -display none -monitor stdio -no-shutdown \
   -accel kvm -M s390-ccw-virtio-3.0 | grep s390x-cpu

Results in:

    /device[0] (host-s390x-cpu)

... so I wonder why that differs from the "query-machines" command?

Anyway, your patch sounds fine, so (with "klass" replaced by "oc"):

Reviewed-by: Thomas Huth <thuth@redhat.com>


Re: [PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by David Hildenbrand 6 years ago
On 21.10.19 11:52, Thomas Huth wrote:
> On 21/10/2019 11.34, David Hildenbrand wrote:
>> We have to set the default model of all machine classes, not just for
>> the active one. Otherwise, "query-machines" will indicate the wrong
>> CPU model ("qemu-s390x-cpu" instead of "host-s390x-cpu") as
>> "default-cpu-type".
>>
>> Doing a
>>      {"execute":"query-machines"}
>> under KVM now results in
>>      {"return": [
>>          {
>>              "hotpluggable-cpus": true,
>>              "name": "s390-ccw-virtio-4.0",
>>              "numa-mem-supported": false,
>>              "default-cpu-type": "host-s390x-cpu",
>>              "cpu-max": 248,
>>              "deprecated": false},
>>          {
>>              "hotpluggable-cpus": true,
>>              "name": "s390-ccw-virtio-2.7",
>>              "numa-mem-supported": false,
>>              "default-cpu-type": "host-s390x-cpu",
>>              "cpu-max": 248,
>>              "deprecated": false
>>          } ...
>>
>> Reported-by: Jiri Denemark <jdenemar@redhat.com>
>> Fixes: b6805e127c6b ("s390x: use generic cpu_model parsing")
>> Cc: Igor Mammedov <imammedo@redhat.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
>> ---
>>   target/s390x/kvm.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index c24c869e77..5966ab0d37 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -320,11 +320,17 @@ void kvm_s390_set_max_pagesize(uint64_t pagesize, Error **errp)
>>       cap_hpage_1m = 1;
>>   }
>>   
>> -int kvm_arch_init(MachineState *ms, KVMState *s)
>> +static void ccw_machine_class_foreach(ObjectClass *klass, void *opaque)
>>   {
>> -    MachineClass *mc = MACHINE_GET_CLASS(ms);
>> +    MachineClass *mc = MACHINE_CLASS(klass);
> 
> I think we rather wanted to avoid using "klass" in new code... maybe use
> "oc" instead of "klass" ?

Can do, this was a copy and paste :)

> 
>>       mc->default_cpu_type = S390_CPU_TYPE_NAME("host");
>> +}
>> +
>> +int kvm_arch_init(MachineState *ms, KVMState *s)
>> +{
>> +    object_class_foreach(ccw_machine_class_foreach, TYPE_S390_CCW_MACHINE,
>> +                         false, NULL);
>>   
>>       if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
>>           error_report("KVM is missing capability KVM_CAP_DEVICE_CTRL - "
>>
> 
> Weird, if you start an older machine, you still get the "host" CPU
> without your patch, too:
> 
> echo -e "info qom-tree \n quit" | \
>   qemu-system-s390x -display none -monitor stdio -no-shutdown \
>     -accel kvm -M s390-ccw-virtio-3.0 | grep s390x-cpu
> 
> Results in:
> 
>      /device[0] (host-s390x-cpu)
> 
> ... so I wonder why that differs from the "query-machines" command?

query-machines probes with the "none" machine all other machines. 
Current code only fixes up the active machine.

(that's why you won't notice when starting a machine - you will always 
get "host" for the active one)

> 
> Anyway, your patch sounds fine, so (with "klass" replaced by "oc"):
> 
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> 


-- 

Thanks,

David / dhildenb


Re: [PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by Thomas Huth 6 years ago
On 21/10/2019 11.54, David Hildenbrand wrote:
> On 21.10.19 11:52, Thomas Huth wrote:
>> On 21/10/2019 11.34, David Hildenbrand wrote:
>>> We have to set the default model of all machine classes, not just for
>>> the active one. Otherwise, "query-machines" will indicate the wrong
>>> CPU model ("qemu-s390x-cpu" instead of "host-s390x-cpu") as
>>> "default-cpu-type".
>>>
>>> Doing a
>>>      {"execute":"query-machines"}
>>> under KVM now results in
>>>      {"return": [
>>>          {
>>>              "hotpluggable-cpus": true,
>>>              "name": "s390-ccw-virtio-4.0",
>>>              "numa-mem-supported": false,
>>>              "default-cpu-type": "host-s390x-cpu",
>>>              "cpu-max": 248,
>>>              "deprecated": false},
>>>          {
>>>              "hotpluggable-cpus": true,
>>>              "name": "s390-ccw-virtio-2.7",
>>>              "numa-mem-supported": false,
>>>              "default-cpu-type": "host-s390x-cpu",
>>>              "cpu-max": 248,
>>>              "deprecated": false
>>>          } ...
>>>
>>> Reported-by: Jiri Denemark <jdenemar@redhat.com>
>>> Fixes: b6805e127c6b ("s390x: use generic cpu_model parsing")
>>> Cc: Igor Mammedov <imammedo@redhat.com>
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>> ---
>>>   target/s390x/kvm.c | 10 ++++++++--
>>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>>> index c24c869e77..5966ab0d37 100644
>>> --- a/target/s390x/kvm.c
>>> +++ b/target/s390x/kvm.c
>>> @@ -320,11 +320,17 @@ void kvm_s390_set_max_pagesize(uint64_t
>>> pagesize, Error **errp)
>>>       cap_hpage_1m = 1;
>>>   }
>>>   -int kvm_arch_init(MachineState *ms, KVMState *s)
>>> +static void ccw_machine_class_foreach(ObjectClass *klass, void *opaque)
>>>   {
>>> -    MachineClass *mc = MACHINE_GET_CLASS(ms);
>>> +    MachineClass *mc = MACHINE_CLASS(klass);
>>
>> I think we rather wanted to avoid using "klass" in new code... maybe use
>> "oc" instead of "klass" ?
> 
> Can do, this was a copy and paste :)
> 
>>
>>>       mc->default_cpu_type = S390_CPU_TYPE_NAME("host");
>>> +}
>>> +
>>> +int kvm_arch_init(MachineState *ms, KVMState *s)
>>> +{
>>> +    object_class_foreach(ccw_machine_class_foreach,
>>> TYPE_S390_CCW_MACHINE,
>>> +                         false, NULL);
>>>         if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
>>>           error_report("KVM is missing capability KVM_CAP_DEVICE_CTRL
>>> - "
>>>
>>
>> Weird, if you start an older machine, you still get the "host" CPU
>> without your patch, too:
>>
>> echo -e "info qom-tree \n quit" | \
>>   qemu-system-s390x -display none -monitor stdio -no-shutdown \
>>     -accel kvm -M s390-ccw-virtio-3.0 | grep s390x-cpu
>>
>> Results in:
>>
>>      /device[0] (host-s390x-cpu)
>>
>> ... so I wonder why that differs from the "query-machines" command?
> 
> query-machines probes with the "none" machine all other machines.
> Current code only fixes up the active machine.
> 
> (that's why you won't notice when starting a machine - you will always
> get "host" for the active one)

Ah, right, thanks for the explanation. I somehow read the patch
description that it is only fixed for the latest one (I should really
read more closely) ... but now it makes perfect sense.

 Thomas


Re: [PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by David Hildenbrand 6 years ago
> query-machines probes with the "none" machine all other machines.
> Current code only fixes up the active machine.
> 

To be more precise, libvirt probes with "-machine none,accel=kvm:tcg" 
all other machines.

> (that's why you won't notice when starting a machine - you will always
> get "host" for the active one)
> 
>>
>> Anyway, your patch sounds fine, so (with "klass" replaced by "oc"):
>>
>> Reviewed-by: Thomas Huth <thuth@redhat.com>
>>
> 
> 


-- 

Thanks,

David / dhildenb


Re: [PATCH v1] s390x/kvm: Set default cpu model for all machine classes
Posted by Cornelia Huck 6 years ago
On Mon, 21 Oct 2019 11:58:35 +0200
David Hildenbrand <david@redhat.com> wrote:

> > query-machines probes with the "none" machine all other machines.
> > Current code only fixes up the active machine.
> >   
> 
> To be more precise, libvirt probes with "-machine none,accel=kvm:tcg" 
> all other machines.

Add that to the patch description?

> 
> > (that's why you won't notice when starting a machine - you will always
> > get "host" for the active one)
> >   
> >>
> >> Anyway, your patch sounds fine, so (with "klass" replaced by "oc"):

Respin with that? Makes it easier to pick up :)

> >>
> >> Reviewed-by: Thomas Huth <thuth@redhat.com>
> >>  
> > 
> >   
> 
>