Re: [PATCH v3 3/3] xen/events: Update virq_to_irq on migration

[Juergen Gross <jgross@suse.com>]

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On 28.08.25 02:36, 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: stable@vger.kernel.org
> Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

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