Commit 783e7706 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

virtio-net: stop/start bh when appropriate 



Avoid sending out packets, and modifying
memory, when VM is stopped.
Add assert statements to verify this does not happen.

Avoid scheduling bh when vhost-net is started.

Stop bh when driver disabled bus mastering
(we must not access memory after this).

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Tested-by: default avatarJason Wang <jasowang@redhat.com>
parent 95477323

hw/virtio-net.c

+50 −16
Original line number Diff line number Diff line
@@ -99,9 +99,14 @@ static void virtio_net_set_config(VirtIODevice *vdev, const uint8_t *config) 
    }

}



static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)

static bool virtio_net_started(VirtIONet *n, uint8_t status)

{

    return (status & VIRTIO_CONFIG_S_DRIVER_OK) &&

        (n->status & VIRTIO_NET_S_LINK_UP) && n->vm_running;

}



static void virtio_net_vhost_status(VirtIONet *n, uint8_t status)

{

    VirtIONet *n = to_virtio_net(vdev);

    if (!n->nic->nc.peer) {

        return;

    }
@@ -112,9 +117,7 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status) 
    if (!tap_get_vhost_net(n->nic->nc.peer)) {

        return;

    }

    if (!!n->vhost_started == ((status & VIRTIO_CONFIG_S_DRIVER_OK) &&

                               (n->status & VIRTIO_NET_S_LINK_UP) &&

                               n->vm_running)) {

    if (!!n->vhost_started == virtio_net_started(n, status)) {

        return;

    }

    if (!n->vhost_started) {
@@ -131,6 +134,32 @@ static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status) 
    }

}



static void virtio_net_set_status(struct VirtIODevice *vdev, uint8_t status)

{

    VirtIONet *n = to_virtio_net(vdev);



    virtio_net_vhost_status(n, status);



    if (!n->tx_waiting) {

        return;

    }



    if (virtio_net_started(n, status) && !n->vhost_started) {

        if (n->tx_timer) {

            qemu_mod_timer(n->tx_timer,

                           qemu_get_clock(vm_clock) + n->tx_timeout);

        } else {

            qemu_bh_schedule(n->tx_bh);

        }

    } else {

        if (n->tx_timer) {

            qemu_del_timer(n->tx_timer);

        } else {

            qemu_bh_cancel(n->tx_bh);

        }

    }

}



static void virtio_net_set_link_status(VLANClientState *nc)

{

    VirtIONet *n = DO_UPCAST(NICState, nc, nc)->opaque;
@@ -675,11 +704,12 @@ static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq) 
{

    VirtQueueElement elem;

    int32_t num_packets = 0;



    if (!(n->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {

        return num_packets;

    }



    assert(n->vm_running);



    if (n->async_tx.elem.out_num) {

        virtio_queue_set_notification(n->tx_vq, 0);

        return num_packets;
@@ -738,6 +768,12 @@ static void virtio_net_handle_tx_timer(VirtIODevice *vdev, VirtQueue *vq) 
{

    VirtIONet *n = to_virtio_net(vdev);



    /* This happens when device was stopped but VCPU wasn't. */

    if (!n->vm_running) {

        n->tx_waiting = 1;

        return;

    }



    if (n->tx_waiting) {

        virtio_queue_set_notification(vq, 1);

        qemu_del_timer(n->tx_timer);
@@ -758,14 +794,19 @@ static void virtio_net_handle_tx_bh(VirtIODevice *vdev, VirtQueue *vq) 
    if (unlikely(n->tx_waiting)) {

        return;

    }

    n->tx_waiting = 1;

    /* This happens when device was stopped but VCPU wasn't. */

    if (!n->vm_running) {

        return;

    }

    virtio_queue_set_notification(vq, 0);

    qemu_bh_schedule(n->tx_bh);

    n->tx_waiting = 1;

}



static void virtio_net_tx_timer(void *opaque)

{

    VirtIONet *n = opaque;

    assert(n->vm_running);



    n->tx_waiting = 0;
@@ -782,6 +823,8 @@ static void virtio_net_tx_bh(void *opaque) 
    VirtIONet *n = opaque;

    int32_t ret;



    assert(n->vm_running);



    n->tx_waiting = 0;



    /* Just in case the driver is not ready on more */
@@ -926,15 +969,6 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id) 
        }

    }

    n->mac_table.first_multi = i;



    if (n->tx_waiting) {

        if (n->tx_timer) {

            qemu_mod_timer(n->tx_timer,

                           qemu_get_clock(vm_clock) + n->tx_timeout);

        } else {

            qemu_bh_schedule(n->tx_bh);

        }

    }

    return 0;

}