virtio-fs: fix MSI-X nvectors calculation

The following MSI-X vectors are required:
 * VIRTIO Configuration Change
 * hiprio virtqueue
 * requests virtqueues

Fix the calculation to reserve enough MSI-X vectors.  Otherwise guest
drivers fall back to a sub-optional configuration where all virtqueues
share a single vector.

This change does not break live migration compatibility since
vhost-user-fs-pci devices are not migratable yet.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20191209110759.35227-1-stefanha@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-12-09 11:07:59 +00:00 committed by Dr. David Alan Gilbert
parent 7038573487
commit 366844f3d1

View File

@ -40,7 +40,8 @@ static void vhost_user_fs_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
DeviceState *vdev = DEVICE(&dev->vdev);
if (vpci_dev->nvectors == DEV_NVECTORS_UNSPECIFIED) {
vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 1;
/* Also reserve config change and hiprio queue vectors */
vpci_dev->nvectors = dev->vdev.conf.num_request_queues + 2;
}
qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus));