6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Andryuk jason.andryuk@amd.com
commit 07ce121d93a5e5fb2440a24da3dbf408fcee978e upstream.
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: Jason Andryuk jason.andryuk@amd.com Reviewed-by: Juergen Gross jgross@suse.com Signed-off-by: Juergen Gross jgross@suse.com Message-ID: 20250828003604.8949-3-jason.andryuk@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/xen/events/events_base.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
--- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1326,10 +1326,12 @@ int bind_interdomain_evtchn_to_irq_latee } 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++) { @@ -1342,12 +1344,16 @@ static int find_virq(unsigned int virq, 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; }
/** @@ -1394,8 +1400,11 @@ int bind_virq_to_irq(unsigned int virq, 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);