From 8f4fd86aa5d6aa122619623910065d236592e37c Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Wed, 6 Jan 2021 15:39:55 +0000 Subject: [PATCH] xen: Set platform PCI device INTX affinity to CPU0 With INTX or GSI delivery, Xen uses the event channel structures of CPU0. If the interrupt gets handled by Linux on a different CPU, then no events are seen as pending. Rather than introducing locking to allow other CPUs to process CPU0's events, just ensure that the PCI interrupts happens only on CPU0. Signed-off-by: David Woodhouse Reviewed-by: Boris Ostrovsky Link: https://lore.kernel.org/r/20210106153958.584169-3-dwmw2@infradead.org Signed-off-by: Juergen Gross --- drivers/xen/platform-pci.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c index 9db557b76511..18f0ed8b1f93 100644 --- a/drivers/xen/platform-pci.c +++ b/drivers/xen/platform-pci.c @@ -132,6 +132,13 @@ static int platform_pci_probe(struct pci_dev *pdev, dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret); goto out; } + /* + * It doesn't strictly *have* to run on CPU0 but it sure + * as hell better process the event channel ports delivered + * to CPU0. + */ + irq_set_affinity(pdev->irq, cpumask_of(0)); + callback_via = get_callback_via(pdev); ret = xen_set_callback_via(callback_via); if (ret) {