[v2] s390x cleanups and CPU hotplug via device_add

[Qemu-devel] [PATCH v2 16/19] s390x: allow cpu hotplug via device_add

Posted by David Hildenbrand 8 years, 2 months ago

E.g. the following now works:
    device_add host-s390-cpu,id=cpu1,core-id=1

The system will perform the same checks as when using cpu_add:
- If the core_id is already in use
- If the next sequential core_id isn't used
- If core-id >= max_cpu is specified

In addition, mixed CPU models are checked. E.g. if starting with
-cpu host and trying to hotplug "qemu-s390-cpu":
    "Mixed CPU models are not supported on s390x."

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/cpu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 105ff13034..be20c2fb0f 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -466,6 +466,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     scc->parent_realize = dc->realize;
     dc->realize = s390_cpu_realizefn;
     dc->props = s390x_cpu_properties;
+    dc->user_creatable = true;
 
     scc->parent_reset = cc->reset;
 #if !defined(CONFIG_USER_ONLY)
-- 
2.13.5

Re: [Qemu-devel] [PATCH v2 16/19] s390x: allow cpu hotplug via device_add

Posted by Matthew Rosato 8 years, 1 month ago

On 09/04/2017 11:43 AM, David Hildenbrand wrote:
> E.g. the following now works:
>     device_add host-s390-cpu,id=cpu1,core-id=1
> 
> The system will perform the same checks as when using cpu_add:
> - If the core_id is already in use
> - If the next sequential core_id isn't used
> - If core-id >= max_cpu is specified
> 
> In addition, mixed CPU models are checked. E.g. if starting with
> -cpu host and trying to hotplug "qemu-s390-cpu":
>     "Mixed CPU models are not supported on s390x."
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>

As easy as flipping a switch, right?

Tested the new device_add path, the old cpu-add path and mixed cases
where I alternated adding cpus via both methods -- looking good.

Reviewed-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>

> ---
>  target/s390x/cpu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
> index 105ff13034..be20c2fb0f 100644
> --- a/target/s390x/cpu.c
> +++ b/target/s390x/cpu.c
> @@ -466,6 +466,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
>      scc->parent_realize = dc->realize;
>      dc->realize = s390_cpu_realizefn;
>      dc->props = s390x_cpu_properties;
> +    dc->user_creatable = true;
> 
>      scc->parent_reset = cc->reset;
>  #if !defined(CONFIG_USER_ONLY)
>

Re: [Qemu-devel] [PATCH v2 16/19] s390x: allow cpu hotplug via device_add

Posted by David Hildenbrand 8 years, 1 month ago

On 07.09.2017 05:16, Matthew Rosato wrote:
> On 09/04/2017 11:43 AM, David Hildenbrand wrote:
>> E.g. the following now works:
>>     device_add host-s390-cpu,id=cpu1,core-id=1
>>
>> The system will perform the same checks as when using cpu_add:
>> - If the core_id is already in use
>> - If the next sequential core_id isn't used
>> - If core-id >= max_cpu is specified
>>
>> In addition, mixed CPU models are checked. E.g. if starting with
>> -cpu host and trying to hotplug "qemu-s390-cpu":
>>     "Mixed CPU models are not supported on s390x."
>>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> As easy as flipping a switch, right?

Yes, luckily all that hotplug handling already was in place, just
core-id vs. id had to be fixed.

> 
> Tested the new device_add path, the old cpu-add path and mixed cases
> where I alternated adding cpus via both methods -- looking good.
> 
> Reviewed-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
> 

Thanks!

-- 

Thanks,

David