Re: [PATCH for-4.22] xen/arm: propagate secondary GIC initialization failures

["Orzel, Michal" <michal.orzel@xxxxxxx>]

On 10-Jul-26 12:20, Mykola Kvach wrote:
> The GICv3 secondary_init() callback can fail while discovering or
> waking a Redistributor, enabling LPIs, or setting up an ITS collection.
> gic_init_secondary_cpu() currently discards that status. start_secondary()
> then marks the CPU online even though its per-CPU GIC interface may be
> unusable.
> 
> Return the callback status through the common GIC layer. Have
> start_secondary() report the failure and stop the affected CPU before it
> is added to cpu_online_map.
> 
> Fixes: bc183a0235e0 ("xen/arm: Add support for GIC v3")
> Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
> ---
>  xen/arch/arm/gic.c             | 10 ++++++++--
>  xen/arch/arm/include/asm/gic.h |  2 +-
>  xen/arch/arm/smpboot.c         |  9 ++++++++-
>  3 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index ee75258fc3..078049e741 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -282,11 +282,17 @@ void smp_send_state_dump(unsigned int cpu)
>  }
>  
>  /* Set up the per-CPU parts of the GIC for a secondary CPU */
> -void gic_init_secondary_cpu(void)
> +int gic_init_secondary_cpu(void)
>  {
> -    gic_hw_ops->secondary_init();
> +    int rc = gic_hw_ops->secondary_init();
> +
> +    if ( rc )
> +        return rc;
> +
>      /* Clear LR mask for secondary cpus */
>      clear_cpu_lr_mask();
> +
> +    return 0;
>  }
>  
>  /* Shut down the per-CPU GIC interface */
> diff --git a/xen/arch/arm/include/asm/gic.h b/xen/arch/arm/include/asm/gic.h
> index ff22dea40d..ee2c26adb4 100644
> --- a/xen/arch/arm/include/asm/gic.h
> +++ b/xen/arch/arm/include/asm/gic.h
> @@ -291,7 +291,7 @@ extern void gic_preinit(void);
>  /* Bring up the interrupt controller, and report # cpus attached */
>  extern void gic_init(void);
>  /* Bring up a secondary CPU's per-CPU GIC interface */
> -extern void gic_init_secondary_cpu(void);
> +extern int gic_init_secondary_cpu(void);
>  /* Take down a CPU's per-CPU GIC interface */
>  extern void gic_disable_cpu(void);
>  /* setup the gic virtual interface for a guest */
> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> index ba5fd2dd52..5e23b0b6a9 100644
> --- a/xen/arch/arm/smpboot.c
> +++ b/xen/arch/arm/smpboot.c
> @@ -319,6 +319,7 @@ smp_prepare_cpus(void)
>  void asmlinkage noreturn start_secondary(void)
>  {
>      unsigned int cpuid = init_data.cpuid;
> +    int rc;
>  
>      memset(get_cpu_info(), 0, sizeof (struct cpu_info));
>  
> @@ -373,7 +374,13 @@ void asmlinkage noreturn start_secondary(void)
>       */
>      update_system_features(&current_cpu_data);
>  
> -    gic_init_secondary_cpu();
> +    rc = gic_init_secondary_cpu();
> +    if ( rc )
> +    {
> +        printk(XENLOG_ERR "CPU%u: Failed to initialize the GIC: %d\n",
> +               cpuid, rc);
NIT: While functionally identical, for consistency with the neighbouring
messages you may want to use smp_processor_id() here instead of cpuid. I can
change on commit.

Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

~Michal