Re: [PATCH] arm/psci: Handle PSCI_ALREADY_ON and PSCI_ON_PENDING as non-fatal

[Julien Grall <julien@xxxxxxx>]

Hi Dmytro,

On 20/06/2026 12:38, Dmytro Prokopchuk1 wrote:
> When bringing up a secondary CPU, call_psci_cpu_on() returns the PSCI
> result codes back to arch_cpu_up(). If the physical CPU is already powered
> on (PSCI_ALREADY_ON) or is powering on (PSCI_ON_PENDING), these negative
> codes are treated as fatal errors. This causes Xen to fail the CPU bring-up.
From my understanding of PSCI CPU_ON, if either ON_PENDING or 
ALREADY_ON is returned then it means the parameters we passed for the 
secondary CPU will not be taken into account.
So always returning PSCI_SUCCESS for the two errors feels wrong. For 
instance, I would expect that the first call to PSCI CPU_ON for a given 
CPU is not meant to return ALREADY_ON/ON_PENDING. It might be fine for 
follow-up call, but such decision should be taken by the function that 
call PSCI CPU_ON multiple time on the same CPU.
I had a brief look at the call stack and I wasn't able to find any loop. 
Can you point me to one?
Cheers,

--
Julien Grall