Commit aff8fd18 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

virtio: turn vq->notification into a nested counter 



Polling should disable virtqueue notifications but that requires nested
virtio_queue_set_notification() calls.  Turn vq->notification into a
counter so it is possible to do nesting.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-10-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 23425cc2

hw/virtio/virtio.c

+12 −6
Original line number Diff line number Diff line
@@ -87,8 +87,8 @@ struct VirtQueue 
    /* Last used index value we have signalled on */

    bool signalled_used_valid;



    /* Notification enabled? */

    bool notification;

    /* Nested host->guest notification disabled counter */

    unsigned int notification_disabled;



    uint16_t queue_index;
@@ -201,7 +201,7 @@ static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) 
static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)

{

    hwaddr pa;

    if (!vq->notification) {

    if (vq->notification_disabled) {

        return;

    }

    pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]);
@@ -210,7 +210,13 @@ static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val) 


void virtio_queue_set_notification(VirtQueue *vq, int enable)

{

    vq->notification = enable;

    if (enable) {

        assert(vq->notification_disabled > 0);

        vq->notification_disabled--;

    } else {

        vq->notification_disabled++;

    }



    if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {

        vring_set_avail_event(vq, vring_avail_idx(vq));

    } else if (enable) {
@@ -959,7 +965,7 @@ void virtio_reset(void *opaque) 
        virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);

        vdev->vq[i].signalled_used = 0;

        vdev->vq[i].signalled_used_valid = false;

        vdev->vq[i].notification = true;

        vdev->vq[i].notification_disabled = 0;

        vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;

        vdev->vq[i].inuse = 0;

    }
@@ -1770,7 +1776,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) 
        vdev->vq[i].vring.desc = qemu_get_be64(f);

        qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);

        vdev->vq[i].signalled_used_valid = false;

        vdev->vq[i].notification = true;

        vdev->vq[i].notification_disabled = 0;



        if (vdev->vq[i].vring.desc) {

            /* XXX virtio-1 devices */