Hi Jens,

On 26/04/2024 09:47, Jens Wiklander wrote:
+static void notif_irq_enable(void *info)
+{
+    struct notif_irq_info *irq_info = info;
+
+    irq_info->ret = setup_irq(irq_info->irq, 0, irq_info->action);
In v2, you were using request_irq(). But now you seem to be open-coding it. Can you explain why?

+    if ( irq_info->ret )
+        printk(XENLOG_ERR "ffa: request_irq irq %u failed: error %d\n",
+               irq_info->irq, irq_info->ret);
+}
+
+void ffa_notif_init(void)
+{
+    const struct arm_smccc_1_2_regs arg = {
+        .a0 = FFA_FEATURES,
+        .a1 = FFA_FEATURE_SCHEDULE_RECV_INTR,
+    };
+    struct notif_irq_info irq_info = { };
+    struct arm_smccc_1_2_regs resp;
+    unsigned int cpu;
+
+    arm_smccc_1_2_smc(&arg, &resp);
+    if ( resp.a0 != FFA_SUCCESS_32 )
+        return;
+
+    irq_info.irq = resp.a2;
+    if ( irq_info.irq < GIC_SGI_STATIC_MAX || irq_info.irq >= NR_GIC_SGI )
+    {
+        printk(XENLOG_ERR "ffa: notification initialization failed: conflicting SGI 
%u\n",
+               irq_info.irq);
+        return;
+    }
+
+    /*
+     * SGIs are per-CPU so we must enable the IRQ on each CPU. We use an
+     * IPI to call notif_irq_enable() on each CPU including the current
+     * CPU. The struct irqaction is preallocated since we can't allocate
+     * memory while in interrupt context.
+     */
+    for_each_online_cpu(cpu)
Even though we currently don't support CPU hotplug, you want to add a CPU Notifier to also register the IRQ when a CPU is onlined ffa_notif_init().

For an example, see time.c. We may also want to consider to enable TEE in presmp_initcalls() so we don't need to have a for_each_online_cpu().

Cheers,

--
Julien Grall

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