Commit 1e7398a1 authored by Pankaj Gupta's avatar Pankaj Gupta Committed by Michael S. Tsirkin
Browse files

vhost: enable vhost without without MSI-X 



We use vhostforce to enable vhost even if Guests don't have MSI-X
support and we fall back to QEMU virtio-net.

This gives a very small performance gain, but the disadvantage
is that guest now controls which virtio code is running
(qemu or vhost) so our attack surface is doubled.

This patch will enable vhost unconditionally whenever it's requested.
For compatibility, enable vhost when vhostforce is set, as well.

Signed-off-by: default avatarPankaj Gupta <pagupta@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarJason Wang <jasowang@redhat.com>
parent 74de5504

hw/net/vhost_net.c

+1 −11
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options) 
    net->dev.vq_index = net->nc->queue_index;



    r = vhost_dev_init(&net->dev, options->opaque,

                       options->backend_type, options->force);

                       options->backend_type);

    if (r < 0) {

        goto fail;

    }
@@ -188,11 +188,6 @@ fail: 
    return NULL;

}



bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)

{

    return vhost_dev_query(&net->dev, dev);

}



static void vhost_net_set_vq_index(struct vhost_net *net, int vq_index)

{

    net->dev.vq_index = vq_index;
@@ -424,11 +419,6 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options) 
    return NULL;

}



bool vhost_net_query(VHostNetState *net, VirtIODevice *dev)

{

    return false;

}



int vhost_net_start(VirtIODevice *dev,

                    NetClientState *ncs,

                    int total_queues)

hw/net/virtio-net.c

+0 −4
Original line number Diff line number Diff line
@@ -128,10 +128,6 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status) 
    if (!n->vhost_started) {

        int r, i;



        if (!vhost_net_query(get_vhost_net(nc->peer), vdev)) {

            return;

        }



        /* Any packets outstanding? Purge them to avoid touching rings

         * when vhost is running.

         */

hw/scsi/vhost-scsi.c

+1 −1
Original line number Diff line number Diff line
@@ -246,7 +246,7 @@ static void vhost_scsi_realize(DeviceState *dev, Error **errp) 
    s->dev.backend_features = 0;



    ret = vhost_dev_init(&s->dev, (void *)(uintptr_t)vhostfd,

                         VHOST_BACKEND_TYPE_KERNEL, true);

                         VHOST_BACKEND_TYPE_KERNEL);

    if (ret < 0) {

        error_setg(errp, "vhost-scsi: vhost initialization failed: %s",

                   strerror(-ret));

hw/virtio/vhost.c

+1 −13
Original line number Diff line number Diff line
@@ -898,7 +898,7 @@ static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq) 
}



int vhost_dev_init(struct vhost_dev *hdev, void *opaque,

                   VhostBackendType backend_type, bool force)

                   VhostBackendType backend_type)

{

    uint64_t features;

    int i, r;
@@ -961,7 +961,6 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque, 
    hdev->started = false;

    hdev->memory_changed = false;

    memory_listener_register(&hdev->memory_listener, &address_space_memory);

    hdev->force = force;

    return 0;

fail_vq:

    while (--i >= 0) {
@@ -989,17 +988,6 @@ void vhost_dev_cleanup(struct vhost_dev *hdev) 
    hdev->vhost_ops->vhost_backend_cleanup(hdev);

}



bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev)

{

    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));

    VirtioBusState *vbus = VIRTIO_BUS(qbus);

    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);



    return !k->query_guest_notifiers ||

           k->query_guest_notifiers(qbus->parent) ||

           hdev->force;

}



/* Stop processing guest IO notifications in qemu.

 * Start processing them in vhost in kernel.

 */

include/hw/virtio/vhost.h

+1 −2
Original line number Diff line number Diff line
@@ -51,7 +51,6 @@ struct vhost_dev { 
    bool log_enabled;

    unsigned long long log_size;

    Error *migration_blocker;

    bool force;

    bool memory_changed;

    hwaddr mem_changed_start_addr;

    hwaddr mem_changed_end_addr;
@@ -61,7 +60,7 @@ struct vhost_dev { 
};



int vhost_dev_init(struct vhost_dev *hdev, void *opaque,

                   VhostBackendType backend_type, bool force);

                   VhostBackendType backend_type);

void vhost_dev_cleanup(struct vhost_dev *hdev);

bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev);

int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev);