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[PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report

Pierre Morel posted 9 patches 3 years, 3 months ago
Maintainers: Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Yanan Wang <wangyanan55@huawei.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Richard Henderson <richard.henderson@linaro.org>, David Hildenbrand <david@redhat.com>
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[PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Pierre Morel 3 years, 3 months ago 
During a subsystem reset the Topology-Change-Report is cleared
by the machine.
Let's ask KVM to clear the Modified Topology Change Report (MTCR)
 bit of the SCA in the case of a subsystem reset.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 target/s390x/cpu.h           |  1 +
 target/s390x/kvm/kvm_s390x.h |  1 +
 hw/s390x/cpu-topology.c      | 12 ++++++++++++
 hw/s390x/s390-virtio-ccw.c   |  1 +
 target/s390x/cpu-sysemu.c    |  7 +++++++
 target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
 6 files changed, 45 insertions(+)

diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index d604aa9c78..9b35795ac8 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
 void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
 int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
                                 int vq, bool assign);
+void s390_cpu_topology_reset(void);
 #ifndef CONFIG_USER_ONLY
 unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
 #else
diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
index aaae8570de..a13c8fb9a3 100644
--- a/target/s390x/kvm/kvm_s390x.h
+++ b/target/s390x/kvm/kvm_s390x.h
@@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
 void kvm_s390_restart_interrupt(S390CPU *cpu);
 void kvm_s390_stop_interrupt(S390CPU *cpu);
 void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
+int kvm_s390_topology_set_mtcr(uint64_t attr);
 
 #endif /* KVM_S390X_H */
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
index c73cebfe6f..9f202621d0 100644
--- a/hw/s390x/cpu-topology.c
+++ b/hw/s390x/cpu-topology.c
@@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState *dev, Error **errp)
     qemu_mutex_init(&topo->topo_mutex);
 }
 
+/**
+ * s390_topology_reset:
+ * @dev: the device
+ *
+ * Calls the sysemu topology reset
+ */
+static void s390_topology_reset(DeviceState *dev)
+{
+    s390_cpu_topology_reset();
+}
+
 /**
  * topology_class_init:
  * @oc: Object class
@@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, void *data)
 
     dc->realize = s390_topology_realize;
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    dc->reset = s390_topology_reset;
 }
 
 static const TypeInfo cpu_topology_info = {
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index aa99a62e42..362378454a 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
     "s390-flic",
     "diag288",
     TYPE_S390_PCI_HOST_BRIDGE,
+    TYPE_S390_CPU_TOPOLOGY,
 };
 
 static void subsystem_reset(void)
diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
index 948e4bd3e0..707c0b658c 100644
--- a/target/s390x/cpu-sysemu.c
+++ b/target/s390x/cpu-sysemu.c
@@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg)
         kvm_s390_set_diag318(cs, arg.host_ulong);
     }
 }
+
+void s390_cpu_topology_reset(void)
+{
+    if (kvm_enabled()) {
+        kvm_s390_topology_set_mtcr(0);
+    }
+}
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index f96630440b..9c994d27d5 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
 {
     return cap_zpci_op;
 }
+
+int kvm_s390_topology_set_mtcr(uint64_t attr)
+{
+    struct kvm_device_attr attribute = {
+        .group = KVM_S390_VM_CPU_TOPOLOGY,
+        .attr  = attr,
+    };
+    int ret;
+
+    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
+        return -EFAULT;
+    }
+    if (!kvm_vm_check_attr(kvm_state, KVM_S390_VM_CPU_TOPOLOGY, attr)) {
+        return -ENOENT;
+    }
+
+    ret = kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attribute);
+    if (ret) {
+        error_report("Failed to set cpu topology attribute %lu: %s",
+                     attr, strerror(-ret));
+    }
+    return ret;
+}
-- 
2.31.1
Re: [PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Thomas Huth 3 years, 3 months ago 
On 12/10/2022 18.21, Pierre Morel wrote:
> During a subsystem reset the Topology-Change-Report is cleared
> by the machine.
> Let's ask KVM to clear the Modified Topology Change Report (MTCR)
>   bit of the SCA in the case of a subsystem reset.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
>   target/s390x/cpu.h           |  1 +
>   target/s390x/kvm/kvm_s390x.h |  1 +
>   hw/s390x/cpu-topology.c      | 12 ++++++++++++
>   hw/s390x/s390-virtio-ccw.c   |  1 +
>   target/s390x/cpu-sysemu.c    |  7 +++++++
>   target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
>   6 files changed, 45 insertions(+)
> 
> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index d604aa9c78..9b35795ac8 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
>   void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
>   int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
>                                   int vq, bool assign);
> +void s390_cpu_topology_reset(void);
>   #ifndef CONFIG_USER_ONLY
>   unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
>   #else
> diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
> index aaae8570de..a13c8fb9a3 100644
> --- a/target/s390x/kvm/kvm_s390x.h
> +++ b/target/s390x/kvm/kvm_s390x.h
> @@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
>   void kvm_s390_restart_interrupt(S390CPU *cpu);
>   void kvm_s390_stop_interrupt(S390CPU *cpu);
>   void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
> +int kvm_s390_topology_set_mtcr(uint64_t attr);
>   
>   #endif /* KVM_S390X_H */
> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
> index c73cebfe6f..9f202621d0 100644
> --- a/hw/s390x/cpu-topology.c
> +++ b/hw/s390x/cpu-topology.c
> @@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState *dev, Error **errp)
>       qemu_mutex_init(&topo->topo_mutex);
>   }
>   
> +/**
> + * s390_topology_reset:
> + * @dev: the device
> + *
> + * Calls the sysemu topology reset
> + */
> +static void s390_topology_reset(DeviceState *dev)
> +{
> +    s390_cpu_topology_reset();
> +}
> +
>   /**
>    * topology_class_init:
>    * @oc: Object class
> @@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, void *data)
>   
>       dc->realize = s390_topology_realize;
>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    dc->reset = s390_topology_reset;
>   }
>   
>   static const TypeInfo cpu_topology_info = {
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index aa99a62e42..362378454a 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
>       "s390-flic",
>       "diag288",
>       TYPE_S390_PCI_HOST_BRIDGE,
> +    TYPE_S390_CPU_TOPOLOGY,
>   };
>   
>   static void subsystem_reset(void)
> diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
> index 948e4bd3e0..707c0b658c 100644
> --- a/target/s390x/cpu-sysemu.c
> +++ b/target/s390x/cpu-sysemu.c
> @@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg)
>           kvm_s390_set_diag318(cs, arg.host_ulong);
>       }
>   }
> +
> +void s390_cpu_topology_reset(void)
> +{
> +    if (kvm_enabled()) {
> +        kvm_s390_topology_set_mtcr(0);
> +    }
> +}
> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
> index f96630440b..9c994d27d5 100644
> --- a/target/s390x/kvm/kvm.c
> +++ b/target/s390x/kvm/kvm.c
> @@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
>   {
>       return cap_zpci_op;
>   }
> +
> +int kvm_s390_topology_set_mtcr(uint64_t attr)
> +{
> +    struct kvm_device_attr attribute = {
> +        .group = KVM_S390_VM_CPU_TOPOLOGY,
> +        .attr  = attr,
> +    };
> +    int ret;
> +
> +    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
> +        return -EFAULT;

EFAULT is something that indicates a bad address (e.g. a segmentation fault) 
... so this definitely sounds like a bad choice for an error code here.

  Thomas
Re: [PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Pierre Morel 3 years, 3 months ago 

On 10/27/22 10:14, Thomas Huth wrote:
> On 12/10/2022 18.21, Pierre Morel wrote:
>> During a subsystem reset the Topology-Change-Report is cleared
>> by the machine.
>> Let's ask KVM to clear the Modified Topology Change Report (MTCR)
>>   bit of the SCA in the case of a subsystem reset.
>>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
>> Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>> ---
>>   target/s390x/cpu.h           |  1 +
>>   target/s390x/kvm/kvm_s390x.h |  1 +
>>   hw/s390x/cpu-topology.c      | 12 ++++++++++++
>>   hw/s390x/s390-virtio-ccw.c   |  1 +
>>   target/s390x/cpu-sysemu.c    |  7 +++++++
>>   target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
>>   6 files changed, 45 insertions(+)
>>
>> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
>> index d604aa9c78..9b35795ac8 100644
>> --- a/target/s390x/cpu.h
>> +++ b/target/s390x/cpu.h
>> @@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
>>   void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
>>   int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t 
>> sch_id,
>>                                   int vq, bool assign);
>> +void s390_cpu_topology_reset(void);
>>   #ifndef CONFIG_USER_ONLY
>>   unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
>>   #else
>> diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
>> index aaae8570de..a13c8fb9a3 100644
>> --- a/target/s390x/kvm/kvm_s390x.h
>> +++ b/target/s390x/kvm/kvm_s390x.h
>> @@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
>>   void kvm_s390_restart_interrupt(S390CPU *cpu);
>>   void kvm_s390_stop_interrupt(S390CPU *cpu);
>>   void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
>> +int kvm_s390_topology_set_mtcr(uint64_t attr);
>>   #endif /* KVM_S390X_H */
>> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
>> index c73cebfe6f..9f202621d0 100644
>> --- a/hw/s390x/cpu-topology.c
>> +++ b/hw/s390x/cpu-topology.c
>> @@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState 
>> *dev, Error **errp)
>>       qemu_mutex_init(&topo->topo_mutex);
>>   }
>> +/**
>> + * s390_topology_reset:
>> + * @dev: the device
>> + *
>> + * Calls the sysemu topology reset
>> + */
>> +static void s390_topology_reset(DeviceState *dev)
>> +{
>> +    s390_cpu_topology_reset();
>> +}
>> +
>>   /**
>>    * topology_class_init:
>>    * @oc: Object class
>> @@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, 
>> void *data)
>>       dc->realize = s390_topology_realize;
>>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>> +    dc->reset = s390_topology_reset;
>>   }
>>   static const TypeInfo cpu_topology_info = {
>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>> index aa99a62e42..362378454a 100644
>> --- a/hw/s390x/s390-virtio-ccw.c
>> +++ b/hw/s390x/s390-virtio-ccw.c
>> @@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
>>       "s390-flic",
>>       "diag288",
>>       TYPE_S390_PCI_HOST_BRIDGE,
>> +    TYPE_S390_CPU_TOPOLOGY,
>>   };
>>   static void subsystem_reset(void)
>> diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
>> index 948e4bd3e0..707c0b658c 100644
>> --- a/target/s390x/cpu-sysemu.c
>> +++ b/target/s390x/cpu-sysemu.c
>> @@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, 
>> run_on_cpu_data arg)
>>           kvm_s390_set_diag318(cs, arg.host_ulong);
>>       }
>>   }
>> +
>> +void s390_cpu_topology_reset(void)
>> +{
>> +    if (kvm_enabled()) {
>> +        kvm_s390_topology_set_mtcr(0);
>> +    }
>> +}
>> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
>> index f96630440b..9c994d27d5 100644
>> --- a/target/s390x/kvm/kvm.c
>> +++ b/target/s390x/kvm/kvm.c
>> @@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
>>   {
>>       return cap_zpci_op;
>>   }
>> +
>> +int kvm_s390_topology_set_mtcr(uint64_t attr)
>> +{
>> +    struct kvm_device_attr attribute = {
>> +        .group = KVM_S390_VM_CPU_TOPOLOGY,
>> +        .attr  = attr,
>> +    };
>> +    int ret;
>> +
>> +    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
>> +        return -EFAULT;
> 
> EFAULT is something that indicates a bad address (e.g. a segmentation 
> fault) ... so this definitely sounds like a bad choice for an error code 
> here.

Hum, yes, ENODEV seems besser no?

> 
>   Thomas
> 
> 

-- 
Pierre Morel
IBM Lab Boeblingen
Re: [PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Cédric Le Goater 3 years, 3 months ago 
On 10/27/22 11:11, Pierre Morel wrote:
> 
> 
> On 10/27/22 10:14, Thomas Huth wrote:
>> On 12/10/2022 18.21, Pierre Morel wrote:
>>> During a subsystem reset the Topology-Change-Report is cleared
>>> by the machine.
>>> Let's ask KVM to clear the Modified Topology Change Report (MTCR)
>>>   bit of the SCA in the case of a subsystem reset.
>>>
>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>>> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
>>> Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>>> ---
>>>   target/s390x/cpu.h           |  1 +
>>>   target/s390x/kvm/kvm_s390x.h |  1 +
>>>   hw/s390x/cpu-topology.c      | 12 ++++++++++++
>>>   hw/s390x/s390-virtio-ccw.c   |  1 +
>>>   target/s390x/cpu-sysemu.c    |  7 +++++++
>>>   target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
>>>   6 files changed, 45 insertions(+)
>>>
>>> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
>>> index d604aa9c78..9b35795ac8 100644
>>> --- a/target/s390x/cpu.h
>>> +++ b/target/s390x/cpu.h
>>> @@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
>>>   void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
>>>   int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
>>>                                   int vq, bool assign);
>>> +void s390_cpu_topology_reset(void);
>>>   #ifndef CONFIG_USER_ONLY
>>>   unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
>>>   #else
>>> diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
>>> index aaae8570de..a13c8fb9a3 100644
>>> --- a/target/s390x/kvm/kvm_s390x.h
>>> +++ b/target/s390x/kvm/kvm_s390x.h
>>> @@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
>>>   void kvm_s390_restart_interrupt(S390CPU *cpu);
>>>   void kvm_s390_stop_interrupt(S390CPU *cpu);
>>>   void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
>>> +int kvm_s390_topology_set_mtcr(uint64_t attr);
>>>   #endif /* KVM_S390X_H */
>>> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
>>> index c73cebfe6f..9f202621d0 100644
>>> --- a/hw/s390x/cpu-topology.c
>>> +++ b/hw/s390x/cpu-topology.c
>>> @@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState *dev, Error **errp)
>>>       qemu_mutex_init(&topo->topo_mutex);
>>>   }
>>> +/**
>>> + * s390_topology_reset:
>>> + * @dev: the device
>>> + *
>>> + * Calls the sysemu topology reset
>>> + */
>>> +static void s390_topology_reset(DeviceState *dev)
>>> +{
>>> +    s390_cpu_topology_reset();
>>> +}
>>> +
>>>   /**
>>>    * topology_class_init:
>>>    * @oc: Object class
>>> @@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, void *data)
>>>       dc->realize = s390_topology_realize;
>>>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>>> +    dc->reset = s390_topology_reset;
>>>   }
>>>   static const TypeInfo cpu_topology_info = {
>>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>>> index aa99a62e42..362378454a 100644
>>> --- a/hw/s390x/s390-virtio-ccw.c
>>> +++ b/hw/s390x/s390-virtio-ccw.c
>>> @@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
>>>       "s390-flic",
>>>       "diag288",
>>>       TYPE_S390_PCI_HOST_BRIDGE,
>>> +    TYPE_S390_CPU_TOPOLOGY,
>>>   };
>>>   static void subsystem_reset(void)
>>> diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
>>> index 948e4bd3e0..707c0b658c 100644
>>> --- a/target/s390x/cpu-sysemu.c
>>> +++ b/target/s390x/cpu-sysemu.c
>>> @@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg)
>>>           kvm_s390_set_diag318(cs, arg.host_ulong);
>>>       }
>>>   }
>>> +
>>> +void s390_cpu_topology_reset(void)
>>> +{
>>> +    if (kvm_enabled()) {
>>> +        kvm_s390_topology_set_mtcr(0);
>>> +    }
>>> +}
>>> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
>>> index f96630440b..9c994d27d5 100644
>>> --- a/target/s390x/kvm/kvm.c
>>> +++ b/target/s390x/kvm/kvm.c
>>> @@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
>>>   {
>>>       return cap_zpci_op;
>>>   }
>>> +
>>> +int kvm_s390_topology_set_mtcr(uint64_t attr)
>>> +{
>>> +    struct kvm_device_attr attribute = {
>>> +        .group = KVM_S390_VM_CPU_TOPOLOGY,
>>> +        .attr  = attr,
>>> +    };
>>> +    int ret;
>>> +
>>> +    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
>>> +        return -EFAULT;
>>
>> EFAULT is something that indicates a bad address (e.g. a segmentation fault) ... so this definitely sounds like a bad choice for an error code here.
> 
> Hum, yes, ENODEV seems besser no?

-ENOTSUP would be 'meilleur' may be ?  :)

C.


> 
>>
>>   Thomas
>>
>>
>
Re: [PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Pierre Morel 3 years, 3 months ago 

On 10/27/22 11:58, Cédric Le Goater wrote:
> On 10/27/22 11:11, Pierre Morel wrote:
>>
>>
>> On 10/27/22 10:14, Thomas Huth wrote:
>>> On 12/10/2022 18.21, Pierre Morel wrote:
>>>> During a subsystem reset the Topology-Change-Report is cleared
>>>> by the machine.
>>>> Let's ask KVM to clear the Modified Topology Change Report (MTCR)
>>>>   bit of the SCA in the case of a subsystem reset.
>>>>
>>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>>>> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
>>>> Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
>>>> ---
>>>>   target/s390x/cpu.h           |  1 +
>>>>   target/s390x/kvm/kvm_s390x.h |  1 +
>>>>   hw/s390x/cpu-topology.c      | 12 ++++++++++++
>>>>   hw/s390x/s390-virtio-ccw.c   |  1 +
>>>>   target/s390x/cpu-sysemu.c    |  7 +++++++
>>>>   target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
>>>>   6 files changed, 45 insertions(+)
>>>>
>>>> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
>>>> index d604aa9c78..9b35795ac8 100644
>>>> --- a/target/s390x/cpu.h
>>>> +++ b/target/s390x/cpu.h
>>>> @@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
>>>>   void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
>>>>   int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t 
>>>> sch_id,
>>>>                                   int vq, bool assign);
>>>> +void s390_cpu_topology_reset(void);
>>>>   #ifndef CONFIG_USER_ONLY
>>>>   unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
>>>>   #else
>>>> diff --git a/target/s390x/kvm/kvm_s390x.h 
>>>> b/target/s390x/kvm/kvm_s390x.h
>>>> index aaae8570de..a13c8fb9a3 100644
>>>> --- a/target/s390x/kvm/kvm_s390x.h
>>>> +++ b/target/s390x/kvm/kvm_s390x.h
>>>> @@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
>>>>   void kvm_s390_restart_interrupt(S390CPU *cpu);
>>>>   void kvm_s390_stop_interrupt(S390CPU *cpu);
>>>>   void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
>>>> +int kvm_s390_topology_set_mtcr(uint64_t attr);
>>>>   #endif /* KVM_S390X_H */
>>>> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
>>>> index c73cebfe6f..9f202621d0 100644
>>>> --- a/hw/s390x/cpu-topology.c
>>>> +++ b/hw/s390x/cpu-topology.c
>>>> @@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState 
>>>> *dev, Error **errp)
>>>>       qemu_mutex_init(&topo->topo_mutex);
>>>>   }
>>>> +/**
>>>> + * s390_topology_reset:
>>>> + * @dev: the device
>>>> + *
>>>> + * Calls the sysemu topology reset
>>>> + */
>>>> +static void s390_topology_reset(DeviceState *dev)
>>>> +{
>>>> +    s390_cpu_topology_reset();
>>>> +}
>>>> +
>>>>   /**
>>>>    * topology_class_init:
>>>>    * @oc: Object class
>>>> @@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, 
>>>> void *data)
>>>>       dc->realize = s390_topology_realize;
>>>>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>>>> +    dc->reset = s390_topology_reset;
>>>>   }
>>>>   static const TypeInfo cpu_topology_info = {
>>>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>>>> index aa99a62e42..362378454a 100644
>>>> --- a/hw/s390x/s390-virtio-ccw.c
>>>> +++ b/hw/s390x/s390-virtio-ccw.c
>>>> @@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
>>>>       "s390-flic",
>>>>       "diag288",
>>>>       TYPE_S390_PCI_HOST_BRIDGE,
>>>> +    TYPE_S390_CPU_TOPOLOGY,
>>>>   };
>>>>   static void subsystem_reset(void)
>>>> diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
>>>> index 948e4bd3e0..707c0b658c 100644
>>>> --- a/target/s390x/cpu-sysemu.c
>>>> +++ b/target/s390x/cpu-sysemu.c
>>>> @@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, 
>>>> run_on_cpu_data arg)
>>>>           kvm_s390_set_diag318(cs, arg.host_ulong);
>>>>       }
>>>>   }
>>>> +
>>>> +void s390_cpu_topology_reset(void)
>>>> +{
>>>> +    if (kvm_enabled()) {
>>>> +        kvm_s390_topology_set_mtcr(0);
>>>> +    }
>>>> +}
>>>> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
>>>> index f96630440b..9c994d27d5 100644
>>>> --- a/target/s390x/kvm/kvm.c
>>>> +++ b/target/s390x/kvm/kvm.c
>>>> @@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
>>>>   {
>>>>       return cap_zpci_op;
>>>>   }
>>>> +
>>>> +int kvm_s390_topology_set_mtcr(uint64_t attr)
>>>> +{
>>>> +    struct kvm_device_attr attribute = {
>>>> +        .group = KVM_S390_VM_CPU_TOPOLOGY,
>>>> +        .attr  = attr,
>>>> +    };
>>>> +    int ret;
>>>> +
>>>> +    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
>>>> +        return -EFAULT;
>>>
>>> EFAULT is something that indicates a bad address (e.g. a segmentation 
>>> fault) ... so this definitely sounds like a bad choice for an error 
>>> code here.
>>
>> Hum, yes, ENODEV seems besser no?
> 
> -ENOTSUP would be 'meilleur' may be ?  :)

yes better :)

thanks,
Pierre

-- 
Pierre Morel
IBM Lab Boeblingen
Re: [PATCH v10 3/9] s390x/cpu_topology: resetting the Topology-Change-Report
Posted by Cédric Le Goater 3 years, 3 months ago 
On 10/12/22 18:21, Pierre Morel wrote:
> During a subsystem reset the Topology-Change-Report is cleared
> by the machine.
> Let's ask KVM to clear the Modified Topology Change Report (MTCR)
>   bit of the SCA in the case of a subsystem reset.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
> ---
>   target/s390x/cpu.h           |  1 +
>   target/s390x/kvm/kvm_s390x.h |  1 +
>   hw/s390x/cpu-topology.c      | 12 ++++++++++++
>   hw/s390x/s390-virtio-ccw.c   |  1 +
>   target/s390x/cpu-sysemu.c    |  7 +++++++
>   target/s390x/kvm/kvm.c       | 23 +++++++++++++++++++++++
>   6 files changed, 45 insertions(+)
> 
> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index d604aa9c78..9b35795ac8 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -825,6 +825,7 @@ void s390_enable_css_support(S390CPU *cpu);
>   void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg);
>   int s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch_id,
>                                   int vq, bool assign);
> +void s390_cpu_topology_reset(void);
>   #ifndef CONFIG_USER_ONLY
>   unsigned int s390_cpu_set_state(uint8_t cpu_state, S390CPU *cpu);
>   #else
> diff --git a/target/s390x/kvm/kvm_s390x.h b/target/s390x/kvm/kvm_s390x.h
> index aaae8570de..a13c8fb9a3 100644
> --- a/target/s390x/kvm/kvm_s390x.h
> +++ b/target/s390x/kvm/kvm_s390x.h
> @@ -46,5 +46,6 @@ void kvm_s390_crypto_reset(void);
>   void kvm_s390_restart_interrupt(S390CPU *cpu);
>   void kvm_s390_stop_interrupt(S390CPU *cpu);
>   void kvm_s390_set_diag318(CPUState *cs, uint64_t diag318_info);
> +int kvm_s390_topology_set_mtcr(uint64_t attr);
>   
>   #endif /* KVM_S390X_H */
> diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
> index c73cebfe6f..9f202621d0 100644
> --- a/hw/s390x/cpu-topology.c
> +++ b/hw/s390x/cpu-topology.c
> @@ -107,6 +107,17 @@ static void s390_topology_realize(DeviceState *dev, Error **errp)
>       qemu_mutex_init(&topo->topo_mutex);
>   }
>   
> +/**
> + * s390_topology_reset:
> + * @dev: the device
> + *
> + * Calls the sysemu topology reset
> + */
> +static void s390_topology_reset(DeviceState *dev)
> +{
> +    s390_cpu_topology_reset();
> +}
> +
>   /**
>    * topology_class_init:
>    * @oc: Object class
> @@ -120,6 +131,7 @@ static void topology_class_init(ObjectClass *oc, void *data)
>   
>       dc->realize = s390_topology_realize;
>       set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    dc->reset = s390_topology_reset;
>   }
>   
>   static const TypeInfo cpu_topology_info = {
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index aa99a62e42..362378454a 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -113,6 +113,7 @@ static const char *const reset_dev_types[] = {
>       "s390-flic",
>       "diag288",
>       TYPE_S390_PCI_HOST_BRIDGE,
> +    TYPE_S390_CPU_TOPOLOGY,
>   };
>   
>   static void subsystem_reset(void)
> diff --git a/target/s390x/cpu-sysemu.c b/target/s390x/cpu-sysemu.c
> index 948e4bd3e0..707c0b658c 100644
> --- a/target/s390x/cpu-sysemu.c
> +++ b/target/s390x/cpu-sysemu.c
> @@ -306,3 +306,10 @@ void s390_do_cpu_set_diag318(CPUState *cs, run_on_cpu_data arg)
>           kvm_s390_set_diag318(cs, arg.host_ulong);
>       }
>   }
> +
> +void s390_cpu_topology_reset(void)
> +{
> +    if (kvm_enabled()) {
> +        kvm_s390_topology_set_mtcr(0);

I would catch and report the errors here.

> +    }
> +}
> diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
> index f96630440b..9c994d27d5 100644
> --- a/target/s390x/kvm/kvm.c
> +++ b/target/s390x/kvm/kvm.c
> @@ -2585,3 +2585,26 @@ int kvm_s390_get_zpci_op(void)
>   {
>       return cap_zpci_op;
>   }
> +
> +int kvm_s390_topology_set_mtcr(uint64_t attr)
> +{
> +    struct kvm_device_attr attribute = {
> +        .group = KVM_S390_VM_CPU_TOPOLOGY,
> +        .attr  = attr,
> +    };
> +    int ret;
> +
> +    if (!s390_has_feat(S390_FEAT_CONFIGURATION_TOPOLOGY)) {
> +        return -EFAULT;
> +    }
> +    if (!kvm_vm_check_attr(kvm_state, KVM_S390_VM_CPU_TOPOLOGY, attr)) {
> +        return -ENOENT;
> +    }
> +
> +    ret = kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attribute);
> +    if (ret) {
> +        error_report("Failed to set cpu topology attribute %lu: %s",
> +                     attr, strerror(-ret));
> +    }
> +    return ret;
> +}

Patchew 2.1-devel-b67e4c2

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