Re: [PATCH v8 07/13] xen/arm: ffa: fix notification SRI across CPU hotplug/suspend

[Mykola Kvach <xakep.amatop@xxxxxxxxx>]

Hi Bertrand,

Thank you for the review.

On Mon, Apr 27, 2026 at 11:22 AM Bertrand Marquis
<Bertrand.Marquis@xxxxxxx> wrote:
>
> Hi Mykola,
>
> > On 2 Apr 2026, at 12:45, Mykola Kvach <xakep.amatop@xxxxxxxxx> wrote:
> >
> > From: Mykola Kvach <mykola_kvach@xxxxxxxx>
> >
> > The FF-A notification SRI interrupt handler was not correctly tied to
> > CPU hotplug and suspend/resume. As a result, CPUs going offline and
> > back online could end up with stale or missing handlers, breaking
> > delivery of FF-A notifications.
> >
> > Signed-off-by: Mykola Kvach <mykola_kvach@xxxxxxxx>
>
> This will probably need a rebase if the harden notification and VM to VM 
> notification
> serie in FF-A is merged first.

I will rebase this patch if the FF-A notification series lands first.

>
> Anyway, changes look good so:
>
> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Thank you, I will add your Reviewed-by.

Best regards,
Mykola

>
> Cheers
> Bertrand
>
> > ---
> > xen/arch/arm/tee/ffa_notif.c | 63 ++++++++++++++++++++++++++++--------
> > 1 file changed, 50 insertions(+), 13 deletions(-)
> >
> > diff --git a/xen/arch/arm/tee/ffa_notif.c b/xen/arch/arm/tee/ffa_notif.c
> > index 186e726412..513c399594 100644
> > --- a/xen/arch/arm/tee/ffa_notif.c
> > +++ b/xen/arch/arm/tee/ffa_notif.c
> > @@ -360,10 +360,28 @@ static int32_t 
> > ffa_notification_bitmap_destroy(uint16_t vm_id)
> >     return ffa_simple_call(FFA_NOTIFICATION_BITMAP_DESTROY, vm_id, 0, 0, 0);
> > }
> >
> > -void ffa_notif_init_interrupt(void)
> > +static DEFINE_PER_CPU_READ_MOSTLY(struct irqaction, sri_irq);
> > +
> > +static int request_sri_irq(void)
> > {
> >     int ret;
> > +    struct irqaction *sri_action = &this_cpu(sri_irq);
> > +
> > +    sri_action->name = "FF-A notif";
> > +    sri_action->handler = notif_irq_handler;
> > +    sri_action->dev_id = NULL;
> > +    sri_action->free_on_release = 0;
> > +
> > +    ret = setup_irq(notif_sri_irq, 0, sri_action);
> > +    if ( ret )
> > +        printk(XENLOG_ERR "ffa: setup_irq irq %u failed: error %d\n",
> > +               notif_sri_irq, ret);
> >
> > +    return ret;
> > +}
> > +
> > +void ffa_notif_init_interrupt(void)
> > +{
> >     if ( fw_notif_enabled && notif_sri_irq < NR_GIC_SGI )
> >     {
> >         /*
> > @@ -376,14 +394,36 @@ void ffa_notif_init_interrupt(void)
> >          * pending, while the SPMC in the secure world will not notice that
> >          * the interrupt was lost.
> >          */
> > -        ret = request_irq(notif_sri_irq, 0, notif_irq_handler, "FF-A 
> > notif",
> > -                          NULL);
> > -        if ( ret )
> > -            printk(XENLOG_ERR "ffa: request_irq irq %u failed: error %d\n",
> > -                   notif_sri_irq, ret);
> > +        request_sri_irq();
> >     }
> > }
> >
> > +static void deinit_ffa_notif_interrupt(void)
> > +{
> > +    if ( fw_notif_enabled && notif_sri_irq < NR_GIC_SGI )
> > +        release_irq(notif_sri_irq, NULL);
> > +}
> > +
> > +static int cpu_ffa_notif_callback(struct notifier_block *nfb,
> > +                                  unsigned long action,
> > +                                  void *hcpu)
> > +{
> > +    switch ( action )
> > +    {
> > +    case CPU_DYING:
> > +        deinit_ffa_notif_interrupt();
> > +        break;
> > +    default:
> > +        break;
> > +    }
> > +
> > +    return NOTIFY_DONE;
> > +}
> > +
> > +static struct notifier_block cpu_ffa_notif_nfb = {
> > +    .notifier_call = cpu_ffa_notif_callback,
> > +};
> > +
> > void ffa_notif_init(void)
> > {
> >     const struct arm_smccc_1_2_regs arg = {
> > @@ -392,7 +432,6 @@ void ffa_notif_init(void)
> >     };
> >     struct arm_smccc_1_2_regs resp;
> >     unsigned int irq;
> > -    int ret;
> >
> >     /* Only enable fw notification if all ABIs we need are supported */
> >     if ( ffa_fw_supports_fid(FFA_NOTIFICATION_BITMAP_CREATE) &&
> > @@ -408,13 +447,11 @@ void ffa_notif_init(void)
> >         notif_sri_irq = irq;
> >         if ( irq >= NR_GIC_SGI )
> >             irq_set_type(irq, IRQ_TYPE_EDGE_RISING);
> > -        ret = request_irq(irq, 0, notif_irq_handler, "FF-A notif", NULL);
> > -        if ( ret )
> > -        {
> > -            printk(XENLOG_ERR "ffa: request_irq irq %u failed: error %d\n",
> > -                   irq, ret);
> > +
> > +        if ( request_sri_irq() )
> >             return;
> > -        }
> > +
> > +        register_cpu_notifier(&cpu_ffa_notif_nfb);
> >         fw_notif_enabled = true;
> >     }
> > }
> > --
> > 2.43.0
> >
>