Commit 366844f3 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Dr. David Alan Gilbert
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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: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20191209110759.35227-1-stefanha@redhat.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent 70385734

hw/virtio/vhost-user-fs-pci.c

+2 −1
Original line number Diff line number Diff line
@@ -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));