[PATCH] virtio_pci: fix cpu affinity support
From: Christoph Hellwig <hch@lst.de>
Date: 2017-08-24 16:07:06
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Commit 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for
virtqueues"") removed the adjustment of the pre_vectors for the virtio
MSI-X vector allocation which was added in commit fb5e31d9 ("virtio:
allow drivers to request IRQ affinity when creating VQs"). This will
lead to an incorrect assignment of MSI-X vectors, and potential
deadlocks when offlining cpus.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Fixes: 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for virtqueues")
Reported-by: YASUAKI ISHIMATSU <redacted>
Cc: stable@vger.kernel.org
---
drivers/virtio/virtio_pci_common.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 007a4f366086..1c4797e53f68 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c@@ -107,6 +107,7 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, { struct virtio_pci_device *vp_dev = to_vp_device(vdev); const char *name = dev_name(&vp_dev->vdev.dev); + unsigned flags = PCI_IRQ_MSIX; unsigned i, v; int err = -ENOMEM;
@@ -126,10 +127,13 @@ static int vp_request_msix_vectors(struct virtio_device *vdev, int nvectors, GFP_KERNEL)) goto error; + if (desc) { + flags |= PCI_IRQ_AFFINITY; + desc->pre_vectors++; /* virtio config vector */ + } + err = pci_alloc_irq_vectors_affinity(vp_dev->pci_dev, nvectors, - nvectors, PCI_IRQ_MSIX | - (desc ? PCI_IRQ_AFFINITY : 0), - desc); + nvectors, flags, desc); if (err < 0) goto error; vp_dev->msix_enabled = 1;
--
2.11.0