Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH 2/2] powerpc/pseries: pass MSI affinity to irq_create_mapping() | Date | Tue, 24 Nov 2020 23:35:34 +0100 |
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On Tue, Nov 24 2020 at 21:03, Laurent Vivier wrote: > With virtio multiqueue, normally each queue IRQ is mapped to a CPU. > > This problem cannot be shown on x86_64 for two reasons:
There is only _ONE_ reason why this is not a problem on x86. x86 uses the generic PCI/MSI domain which supports this out of the box.
> - the call path traverses arch_setup_msi_irqs() that is arch specific: > > virtscsi_probe() > virtscsi_init() > vp_modern_find_vqs() > vp_find_vqs() > vp_find_vqs_msix() > pci_alloc_irq_vectors_affinity() > __pci_enable_msix_range() > pci_msi_setup_msi_irqs() > arch_setup_msi_irqs() > rtas_setup_msi_irqs()
This is a problem on _all_ variants of PPC MSI providers, not only for pseries. It's not restricted to virtscsi devices either, that's just the device which made you discover this.
Thanks,
tglx
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