[v1] Implement CPU hotplug on Arm

[PATCH v1 0/4] Implement CPU hotplug on Arm

Posted by Mykyta Poturai 2 weeks, 2 days ago

This series implements support for CPU hotplug/unplug on Arm. To achieve this,
several things need to be done:

1. XEN_SYSCTL_CPU_HOTPLUG_* calls implemented.
2. timer and GIC maintenance interrupts switched to static irqactions to remove
the need for freeing them during release_irq.
3. Enabled the build of xen-hptool on Arm.

Tested on QEMU.

Mykyta Poturai (4):
  arm/time: Use static irqaction
  arm/gic: Use static irqaction
  arm/sysctl: Implement cpu hotplug ops
  tools: Allow building xen-hptool without CONFIG_MIGRATE

 config/arm64.mk                  |  1 +
 config/x86_32.mk                 |  1 +
 config/x86_64.mk                 |  1 +
 tools/libs/guest/Makefile.common |  4 +-
 tools/misc/Makefile              |  2 +-
 xen/arch/arm/gic.c               | 10 ++++-
 xen/arch/arm/sysctl.c            | 67 ++++++++++++++++++++++++++++++++
 xen/arch/arm/time.c              | 20 ++++++++--
 8 files changed, 98 insertions(+), 8 deletions(-)

-- 
2.34.1

Re: [PATCH v1 0/4] Implement CPU hotplug on Arm

Posted by Grygorii Strashko 1 week, 4 days ago

Hi Mykyta,

Thank a lot for your patches.

On 18.09.25 15:16, Mykyta Poturai wrote:
> This series implements support for CPU hotplug/unplug on Arm. To achieve this,
> several things need to be done:
> 
> 1. XEN_SYSCTL_CPU_HOTPLUG_* calls implemented.
> 2. timer and GIC maintenance interrupts switched to static irqactions to remove
> the need for freeing them during release_irq.
> 3. Enabled the build of xen-hptool on Arm.
> 
> Tested on QEMU.
> 
> Mykyta Poturai (4):
>    arm/time: Use static irqaction
>    arm/gic: Use static irqaction
>    arm/sysctl: Implement cpu hotplug ops
>    tools: Allow building xen-hptool without CONFIG_MIGRATE
> 
>   config/arm64.mk                  |  1 +
>   config/x86_32.mk                 |  1 +
>   config/x86_64.mk                 |  1 +
>   tools/libs/guest/Makefile.common |  4 +-
>   tools/misc/Makefile              |  2 +-
>   xen/arch/arm/gic.c               | 10 ++++-
>   xen/arch/arm/sysctl.c            | 67 ++++++++++++++++++++++++++++++++
>   xen/arch/arm/time.c              | 20 ++++++++--
>   8 files changed, 98 insertions(+), 8 deletions(-)
> 

Hence you introducing new feature for ARM I'd very much appreciated if you
add corresponding documentation under docs/hypervisor-guide/arm/.

-- 
Best regards,
-grygorii

Re: [PATCH v1 0/4] Implement CPU hotplug on Arm

Posted by Julien Grall 1 week, 4 days ago

Hi Grygorii,

On 23/09/2025 17:09, Grygorii Strashko wrote:
> On 18.09.25 15:16, Mykyta Poturai wrote:
>> This series implements support for CPU hotplug/unplug on Arm. To 
>> achieve this,
>> several things need to be done:
>>
>> 1. XEN_SYSCTL_CPU_HOTPLUG_* calls implemented.
>> 2. timer and GIC maintenance interrupts switched to static irqactions 
>> to remove
>> the need for freeing them during release_irq.
>> 3. Enabled the build of xen-hptool on Arm.
>>
>> Tested on QEMU.
>>
>> Mykyta Poturai (4):
>>    arm/time: Use static irqaction
>>    arm/gic: Use static irqaction
>>    arm/sysctl: Implement cpu hotplug ops
>>    tools: Allow building xen-hptool without CONFIG_MIGRATE
>>
>>   config/arm64.mk                  |  1 +
>>   config/x86_32.mk                 |  1 +
>>   config/x86_64.mk                 |  1 +
>>   tools/libs/guest/Makefile.common |  4 +-
>>   tools/misc/Makefile              |  2 +-
>>   xen/arch/arm/gic.c               | 10 ++++-
>>   xen/arch/arm/sysctl.c            | 67 ++++++++++++++++++++++++++++++++
>>   xen/arch/arm/time.c              | 20 ++++++++--
>>   8 files changed, 98 insertions(+), 8 deletions(-)
>>
> 
> Hence you introducing new feature for ARM I'd very much appreciated if you
> add corresponding documentation under docs/hypervisor-guide/arm/.

I think some documentation is good. But why does this need to be Arm 
specific?

Cheers,

-- 
Julien Grall

Re: [PATCH v1 0/4] Implement CPU hotplug on Arm

Posted by Grygorii Strashko 1 week, 2 days ago


On 23.09.25 21:38, Julien Grall wrote:
> Hi Grygorii,
> 
> On 23/09/2025 17:09, Grygorii Strashko wrote:
>> On 18.09.25 15:16, Mykyta Poturai wrote:
>>> This series implements support for CPU hotplug/unplug on Arm. To achieve this,
>>> several things need to be done:
>>>
>>> 1. XEN_SYSCTL_CPU_HOTPLUG_* calls implemented.
>>> 2. timer and GIC maintenance interrupts switched to static irqactions to remove
>>> the need for freeing them during release_irq.
>>> 3. Enabled the build of xen-hptool on Arm.
>>>
>>> Tested on QEMU.
>>>
>>> Mykyta Poturai (4):
>>>    arm/time: Use static irqaction
>>>    arm/gic: Use static irqaction
>>>    arm/sysctl: Implement cpu hotplug ops
>>>    tools: Allow building xen-hptool without CONFIG_MIGRATE
>>>
>>>   config/arm64.mk                  |  1 +
>>>   config/x86_32.mk                 |  1 +
>>>   config/x86_64.mk                 |  1 +
>>>   tools/libs/guest/Makefile.common |  4 +-
>>>   tools/misc/Makefile              |  2 +-
>>>   xen/arch/arm/gic.c               | 10 ++++-
>>>   xen/arch/arm/sysctl.c            | 67 ++++++++++++++++++++++++++++++++
>>>   xen/arch/arm/time.c              | 20 ++++++++--
>>>   8 files changed, 98 insertions(+), 8 deletions(-)
>>>
>>
>> Hence you introducing new feature for ARM I'd very much appreciated if you
>> add corresponding documentation under docs/hypervisor-guide/arm/.
> 
> I think some documentation is good. But why does this need to be Arm specific?

Only because this series is for ARM, if it could be generic (at least partially) - even better.


-- 
Best regards,
-grygorii