4.12-stable review patch. If anyone has any objections, please let me know.
------------------ From: Christoph Hellwig <[email protected]> commit ba74b6f7fcc07355d087af6939712eed4a454821 upstream. 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 <[email protected]> Fixes: 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for virtqueues") Reported-by: YASUAKI ISHIMATSU <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/virtio/virtio_pci_common.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -107,6 +107,7 @@ static int vp_request_msix_vectors(struc { 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(struc 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;
