[PATCH v3 2/2] powerpc/pseries: pass MSI affinity to irq_create_mapping()

Laurent Vivier
2020-11-25T15:10:04Z

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

But since commit 0d9f0a52c8b9f ("virtio_scsi: use virtio IRQ affinity")
this is broken on pseries.

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.

As the previous patch has added the affinity parameter to
irq_create_mapping() we can forward the affinity from rtas_setup_msi_irqs()
to irq_domain_alloc_descs().

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

BugId: https://bugzilla.redhat.com/show_bug.cgi?id=1702939
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
---
arch/powerpc/platforms/pseries/msi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/msi.c b/arch/powerpc/platforms/pseries/msi.c
index 133f6adcb39c..b3ac2455faad 100644
--- a/arch/powerpc/platforms/pseries/msi.c
+++ b/arch/powerpc/platforms/pseries/msi.c
@@ -458,7 +458,8 @@ static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec_in, int type)
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);
--
2.28.0