Re: [PATCH v5 05/12] xen/arm: irq: avoid local IRQ descriptors reinit on system resume

[Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>]

Mykola Kvach <xakep.amatop@gmail.com> writes:

> From: Mykola Kvach <mykola_kvach@epam.com>
>
> On ARM, during system resume, CPUs are brought online again. This normally
> triggers init_local_irq_data, which reinitializes IRQ descriptors for
> banked interrupts (SGIs and PPIs).
>
> These descriptors are statically allocated per CPU and retain valid
> state across suspend/resume cycles. Re-initializing them on resume is
> unnecessary and may result in loss of interrupt configuration or
> restored state.
>
> This patch skips init_local_irq_data when system_state is set to
> SYS_STATE_resume to preserve banked IRQ descs state during resume.
>
> Signed-off-by: Mykola Kvach <mykola_kvach@epam.com>

Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>

> ---
>  xen/arch/arm/irq.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
> index 4bbf0b0664..148f184f8b 100644
> --- a/xen/arch/arm/irq.c
> +++ b/xen/arch/arm/irq.c
> @@ -122,6 +122,10 @@ static int cpu_callback(struct notifier_block *nfb, unsigned long action,
>      switch ( action )
>      {
>      case CPU_UP_PREPARE:
> +        /* Skip local IRQ cleanup on resume */
> +        if ( system_state == SYS_STATE_resume )
> +            break;
> +
>          rc = init_local_irq_data(cpu);
>          if ( rc )
>              printk(XENLOG_ERR "Unable to allocate local IRQ for CPU%u\n",

-- 
WBR, Volodymyr