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vhost: enable vhost without without MSI-X

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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: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Pankaj Gupta 2015-06-16 13:48:59 +05:30 • committed by Michael S. Tsirkin
parent 74de5504fd
commit 1e7398a140
8 changed files with 4 additions and 35 deletions
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14
hw/virtio/vhost.c
View file

@ -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.
*/