On 26.08.25 02:55, Jason Andryuk wrote:
VIRQs come in 3 flavors, per-VPU, per-domain, and global, and the VIRQs are tracked in per-cpu virq_to_irq arrays.Per-domain and global VIRQs must be bound on CPU 0, and bind_virq_to_irq() sets the per_cpu virq_to_irq at registration time Later, the interrupt can migrate, and info->cpu is updated. When calling __unbind_from_irq(), the per-cpu virq_to_irq is cleared for a different cpu. If bind_virq_to_irq() is called again with CPU 0, the stale irq is returned. There won't be any irq_info for the irq, so things break. Make xen_rebind_evtchn_to_cpu() update the per_cpu virq_to_irq mappings to keep them update to date with the current cpu. This ensures the correct virq_to_irq is cleared in __unbind_from_irq(). Fixes: e46cdb66c8fc ("xen: event channels") Cc: [email protected] Signed-off-by: Jason Andryuk <[email protected]> --- V2: Different approach changing virq_to_irq --- drivers/xen/events/events_base.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index a85bc43f4344..4e9db7b92dde 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -1772,6 +1772,7 @@ static int xen_rebind_evtchn_to_cpu(struct irq_info *info, unsigned int tcpu) { struct evtchn_bind_vcpu bind_vcpu; evtchn_port_t evtchn = info ? info->evtchn : 0; + int old_cpu = info ? info->cpu : tcpu;
I'd prefer not to initialize old_cpu just here ...
if (!VALID_EVTCHN(evtchn))
return -1;
... as here info is always valid, so you can just use "old_cpu = info->cpu;" (probably just after the hypercall).
@@ -1795,8 +1796,18 @@ static int xen_rebind_evtchn_to_cpu(struct irq_info
*info, unsigned int tcpu)
* it, but don't do the xenlinux-level rebind in that case.
*/
if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
+ {
Kernel style, please.
bind_evtchn_to_cpu(info, tcpu, false);+ if (info->type == IRQT_VIRQ) {+ int virq = info->u.virq; + int irq = per_cpu(virq_to_irq, old_cpu)[virq]; + + per_cpu(virq_to_irq, old_cpu)[virq] = -1; + per_cpu(virq_to_irq, tcpu)[virq] = irq; + } + } + do_unmask(info, EVT_MASK_REASON_TEMPORARY);return 0;
Juergen
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