[PATCH 5.4 29/54] powerpc/pseries: Pass MSI affinity to irq_create_mapping()

Greg Kroah-Hartman
2020-12-10T15:33:59Z

From: Laurent Vivier <lvivier@redhat.com>

commit 9ea69a55b3b9a71cded9726af591949c1138f235 upstream.

With virtio multiqueue, normally each queue IRQ is mapped to a CPU.

Commit 0d9f0a52c8b9f ("virtio_scsi: use virtio IRQ affinity") exposed
an existing shortcoming of the arch code by moving virtio_scsi to
the automatic IRQ affinity assignment.

The affinity is correctly computed in msi_desc but this is not applied
to the system IRQs.

It appears the affinity is correctly passed to rtas_setup_msi_irqs() but
lost at this point and never passed to irq_domain_alloc_descs()
(see commit 06ee6d571f0e ("genirq: Add affinity hint to irq allocation"))
because irq_create_mapping() doesn't take an affinity parameter.

Use the new irq_create_mapping_affinity() function, which allows to forward
the affinity setting from rtas_setup_msi_irqs() to irq_domain_alloc_descs().

With this change, the virtqueues are correctly dispatched between the CPUs
on pseries.

Fixes: e75eafb9b039 ("genirq/msi: Switch to new irq spreading infrastructure")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kurz <groug@kaod.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201126082852.1178497-3-lvivier@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/powerpc/platforms/pseries/msi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -458,7 +458,8 @@ again:
return hwirq;
}

- virq = irq_create_mapping(NULL, hwirq);
+ virq = irq_create_mapping_affinity(NULL, hwirq,
+ entry->affinity);

if (!virq) {
pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);