Commit 07ce121d authored by Jason Andryuk's avatar Jason Andryuk Committed by Juergen Gross
Browse files

xen/events: Return -EEXIST for bound VIRQs 



Change find_virq() to return -EEXIST when a VIRQ is bound to a
different CPU than the one passed in.  With that, remove the BUG_ON()
from bind_virq_to_irq() to propogate the error upwards.

Some VIRQs are per-cpu, but others are per-domain or global.  Those must
be bound to CPU0 and can then migrate elsewhere.  The lookup for
per-domain and global will probably fail when migrated off CPU 0,
especially when the current CPU is tracked.  This now returns -EEXIST
instead of BUG_ON().

A second call to bind a per-domain or global VIRQ is not expected, but
make it non-fatal to avoid trying to look up the irq, since we don't
know which per_cpu(virq_to_irq) it will be in.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarJason Andryuk <jason.andryuk@amd.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Message-ID: <20250828003604.8949-3-jason.andryuk@amd.com>
parent 08df2d7d

drivers/xen/events/events_base.c

+14 −5
Original line number Diff line number Diff line
@@ -1314,10 +1314,12 @@ int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev, 
}

EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq_lateeoi);



static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn)

static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn,

		     bool percpu)

{

	struct evtchn_status status;

	evtchn_port_t port;

	bool exists = false;



	memset(&status, 0, sizeof(status));

	for (port = 0; port < xen_evtchn_max_channels(); port++) {
@@ -1330,12 +1332,16 @@ static int find_virq(unsigned int virq, unsigned int cpu, evtchn_port_t *evtchn) 
			continue;

		if (status.status != EVTCHNSTAT_virq)

			continue;

		if (status.u.virq == virq && status.vcpu == xen_vcpu_nr(cpu)) {

		if (status.u.virq != virq)

			continue;

		if (status.vcpu == xen_vcpu_nr(cpu)) {

			*evtchn = port;

			return 0;

		} else if (!percpu) {

			exists = true;

		}

	}

	return -ENOENT;

	return exists ? -EEXIST : -ENOENT;

}



/**
@@ -1382,8 +1388,11 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu) 
			evtchn = bind_virq.port;

		else {

			if (ret == -EEXIST)

				ret = find_virq(virq, cpu, &evtchn);

			BUG_ON(ret < 0);

				ret = find_virq(virq, cpu, &evtchn, percpu);

			if (ret) {

				__unbind_from_irq(info, info->irq);

				goto out;

			}

		}



		ret = xen_irq_info_virq_setup(info, cpu, evtchn, virq);