[PATCH 2/2] hotplug-cpu.c: set UNISOLATE on dlpar_cpu_remove() failure

Michael Ellerman mpe at ellerman.id.au
Tue Apr 20 13:57:34 AEST 2021


Daniel Henrique Barboza <danielhb413 at gmail.com> writes:
> On 4/19/21 9:48 AM, Michael Ellerman wrote:
>> Daniel Henrique Barboza <danielhb413 at gmail.com> writes:
>>> The RTAS set-indicator call, when attempting to UNISOLATE a DRC that is
>>> already UNISOLATED or CONFIGURED, returns RTAS_OK and does nothing else
>>> for both QEMU and phyp. This gives us an opportunity to use this
>>> behavior to signal the hypervisor layer when an error during device
>>> removal happens, allowing it to do a proper error handling, while not
>>> breaking QEMU/phyp implementations that don't have this support.
>>>
>>> This patch introduces this idea by unisolating all CPU DRCs that failed
>>> to be removed by dlpar_cpu_remove_by_index(), when handling the
>>> PSERIES_HP_ELOG_ID_DRC_INDEX event. This is being done for this event
>>> only because its the only CPU removal event QEMU uses, and there's no
>>> need at this moment to add this mechanism for phyp only code.
>> 
>> Have you also confirmed that phyp is not bothered by it? ie. everything
>> seems to continue working when you trigger this path on phyp.
>
> Yes. Daniel Bueso (dbuesom at us.ibm.com) from the partition firmware team
> helped me with that. We confirmed that phyp returns RTAS_OK under these
> conditions (Unisolating an unisolated/configured DRC).

Thanks.

cheers


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