Commit fb20fbb7 authored by Jia He's avatar Jia He Committed by Michael S. Tsirkin
Browse files

vhost: avoid to start/stop virtqueue which is not ready 



In our Armv8a server, we try to configure the vhost scsi but fail
to boot up the guest (-machine virt-2.10). The guest's boot failure
is very early, even earlier than grub.

There are 3 virtqueues (ctrl, event and cmd) for virtio scsi device,
but ovmf and seabios will only set the physical address for the 3rd
one (cmd). Then in vhost_virtqueue_start(), virtio_queue_get_desc_addr
will be 0 for ctrl and event vq when qemu negotiates with ovmf. So
vhost_memory_map fails with ENOMEM.

This patch just fixs it by early quitting the virtqueue start/stop
when virtio_queue_get_desc_addr is 0.

Btw, after guest kernel starts, all the 3 queues will be initialized
and set address correctly.

Already tested on Arm64 and X86_64 qemu.

Signed-off-by: default avatarJia He <jia.he@hxt-semitech.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 9e2a2a3e

hw/virtio/vhost.c

+17 −1
Original line number Diff line number Diff line
@@ -345,6 +345,10 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev, 
    for (i = 0; i < dev->nvqs; ++i) {

        struct vhost_virtqueue *vq = dev->vqs + i;



        if (vq->desc_phys == 0) {

            continue;

        }



        j = 0;

        r = vhost_verify_ring_part_mapping(

                vq->desc, vq->desc_phys, vq->desc_size,
@@ -881,6 +885,11 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, 
    };

    struct VirtQueue *vvq = virtio_get_queue(vdev, idx);



    a = virtio_queue_get_desc_addr(vdev, idx);

    if (a == 0) {

        /* Queue might not be ready for start */

        return 0;

    }



    vq->num = state.num = virtio_queue_get_num(vdev, idx);

    r = dev->vhost_ops->vhost_set_vring_num(dev, &state);
@@ -906,7 +915,7 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, 
    }



    vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx);

    vq->desc_phys = a = virtio_queue_get_desc_addr(vdev, idx);

    vq->desc_phys = a;

    vq->desc = vhost_memory_map(dev, a, &l, 0);

    if (!vq->desc || l != s) {

        r = -ENOMEM;
@@ -989,6 +998,13 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, 
        .index = vhost_vq_index,

    };

    int r;

    int a;



    a = virtio_queue_get_desc_addr(vdev, idx);

    if (a == 0) {

        /* Don't stop the virtqueue which might have not been started */

        return;

    }



    r = dev->vhost_ops->vhost_get_vring_base(dev, &state);

    if (r < 0) {