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Re: [XEN PATCH v4 5/5] xen/arm: ffa: support notification
Hi Jens,
On 02/05/2024 15:56, Jens Wiklander wrote:
-static bool ffa_probe(void)
+static int __init ffa_init(void)
{
uint32_t vers;
unsigned int major_vers;
@@ -460,16 +511,16 @@ static bool ffa_probe(void)
printk(XENLOG_ERR
"ffa: unsupported SMCCC version %#x (need at least %#x)\n",
smccc_ver, ARM_SMCCC_VERSION_1_2);
- return false;
+ return 0;
}
if ( !ffa_get_version(&vers) )
- return false;
+ return 0;
if ( vers < FFA_MIN_SPMC_VERSION || vers > FFA_MY_VERSION )
{
printk(XENLOG_ERR "ffa: Incompatible version %#x found\n", vers);
- return false;
+ return 0;
}
major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT) & FFA_VERSION_MAJOR_MASK;
@@ -492,26 +543,33 @@ static bool ffa_probe(void)
!check_mandatory_feature(FFA_MEM_SHARE_32) ||
!check_mandatory_feature(FFA_MEM_RECLAIM) ||
!check_mandatory_feature(FFA_MSG_SEND_DIRECT_REQ_32) )
- return false;
+ return 0;
if ( !ffa_rxtx_init() )
- return false;
+ return 0;
ffa_version = vers;
if ( !ffa_partinfo_init() )
goto err_rxtx_destroy;
+ ffa_notif_init();
INIT_LIST_HEAD(&ffa_teardown_head);
init_timer(&ffa_teardown_timer, ffa_teardown_timer_callback, NULL, 0);
- return true;
+ return 0;
err_rxtx_destroy:
ffa_rxtx_destroy();
ffa_version = 0;
- return false;
+ return 0;
+}
+presmp_initcall(ffa_init);
I would rather prefer if tee_init() is called from presmp_initcall().
This would avoid FFA to have to try to initialize itself before all the
others.
This is what I had in mind with my original request, but I guess I
wasn't clear enough. Sorry for that.
[...]
+static void notif_irq_handler(int irq, void *data)
+{
+ const struct arm_smccc_1_2_regs arg = {
+ .a0 = FFA_NOTIFICATION_INFO_GET_64,
+ };
+ struct arm_smccc_1_2_regs resp;
+ unsigned int id_pos;
+ unsigned int list_count;
+ uint64_t ids_count;
+ unsigned int n;
+ int32_t res;
+
+ do {
+ arm_smccc_1_2_smc(&arg, &resp);
+ res = ffa_get_ret_code(&resp);
+ if ( res )
+ {
+ if ( res != FFA_RET_NO_DATA )
+ printk(XENLOG_ERR "ffa: notification info get failed: error
%d\n",
+ res);
+ return;
+ }
+
+ ids_count = resp.a2 >> FFA_NOTIF_INFO_GET_ID_LIST_SHIFT;
+ list_count = ( resp.a2 >> FFA_NOTIF_INFO_GET_ID_COUNT_SHIFT ) &
+ FFA_NOTIF_INFO_GET_ID_COUNT_MASK;
+
+ id_pos = 0;
+ for ( n = 0; n < list_count; n++ )
+ {
+ unsigned int count = ((ids_count >> 2 * n) & 0x3) + 1;
+ uint16_t vm_id = get_id_from_resp(&resp, id_pos);
+ struct domain *d;
+
+ /*
+ * vm_id == 0 means a notifications pending for Xen itself, but
+ * we don't support that yet.
+ */
+ if (vm_id)
+ d = ffa_rcu_lock_domain_by_vm_id(vm_id);
I am still unconvinced that this is sufficient. This will prevent
"struct domain *" to be freed. But ...
+ else
+ d = NULL;
+
+ if ( d )
+ {
+ struct ffa_ctx *ctx = d->arch.tee;
... I don't think it will protect d->arch.tee to be freed as this is
happening during teardorwn. You mostly need some other sort of locking
to avoid d->arch.tee been freed behind your back.
+ struct vcpu *v;
+
+ ACCESS_ONCE(ctx->notif.secure_pending) = true;
+
+ /*
+ * Since we're only delivering global notification, always
+ * deliver to the first online vCPU. It doesn't matter
+ * which we chose, as long as it's available.
+ */
+ for_each_vcpu(d, v)
+ {
+ if ( is_vcpu_online(v) )
+ {
+ vgic_inject_irq(d, v, GUEST_FFA_NOTIF_PEND_INTR_ID,
+ true);
+ break;
+ }
+ }
+ if ( !v )
+ printk(XENLOG_ERR "ffa: can't inject NPI, all vCPUs
offline\n");
+
+ rcu_unlock_domain(d);
+ }
+
+ id_pos += count;
+ }
+
+ } while (resp.a2 & FFA_NOTIF_INFO_GET_MORE_FLAG);
+}
[...]
+static int ffa_setup_irq_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ struct notif_irq_info irq_info = { };
+
+ switch ( action )
+ {
+ case CPU_ONLINE:
Can't you execute the notifier in CPU_STARTING? This will be called on
the CPU directly, so you should be able to use request_irq(...).
+ /*
+ * The notifier call is done on the primary or initiating CPU when
+ * the target CPU have come online, but the SGI must be setup on
+ * the target CPU.
+ *
+ * We make an IPI call to the target CPU to setup the SGI. The call
+ * is executed in interrupt context on the target CPU, so we can't
+ * call request_irq() directly since it allocates memory.
+ *
+ * We preallocate the needed irqaction here and pass it via the
+ * temporary struct notif_irq_info. The call is synchronous in the
+ * sense that when on_selected_cpus() returns the callback
+ * notif_irq_enable() has done the same on the target CPU.
+ *
+ * We deal with two errors, one where notif_irq_enable() hasn't
+ * been called for some reason, that error is logged below. The
+ * other where setup_irq() fails is logged in the callback. We must
+ * free the irqaction in both cases since it has failed to become
+ * registered.
+ *
+ * Failures leads to a problem notifications, the CPUs with failure
+ * will trigger on the SGI indicating that there are notifications
+ * pending, while the SPMC in the secure world will not notice that
+ * the interrupt was lost.
+ */
+ irq_info.action = xmalloc(struct irqaction);
+ if ( !irq_info.action )
+ {
+ printk(XENLOG_ERR "ffa: setup irq %u failed, out of memory\n",
+ notif_sri_irq);
+ return -ENOMEM;
+ }
+
+ *irq_info.action = (struct irqaction){
+ .handler = notif_irq_handler,
+ .name = "FF-A notif",
+ .free_on_release = 1,
+ };
+
+ on_selected_cpus(cpumask_of(cpu), notif_irq_enable, &irq_info, 1);
+ if (!irq_info.called)
+ printk(XENLOG_ERR "ffa: on_selected_cpus(cpumask_of(%u)) failed\n",
+ cpu);
+ /*
+ * The irqaction is unused and must be freed if irq_info.action is
+ * non-NULL at this stage.
+ */
+ XFREE(irq_info.action);
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
Cheers,
--
Julien Grall
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