linux/drivers/vhost
Kangjie Xu 313389be06 vhost-net: support VIRTIO_F_RING_RESET
Add VIRTIO_F_RING_RESET, which indicates that the driver can reset a
queue individually.

VIRTIO_F_RING_RESET feature is added to virtio-spec 1.2. The relevant
information is in
    oasis-tcs/virtio-spec#124
    oasis-tcs/virtio-spec#139

The implementation only adds the feature bit in supported features. It
does not require any other changes because we reuse the existing vhost
protocol.

The virtqueue reset process can be concluded as two parts:
1. The driver can reset a virtqueue. When it is triggered, we use the
set_backend to disable the virtqueue.
2. After the virtqueue is disabled, the driver may optionally re-enable
it. The process is basically similar to when the device is started,
except that the restart process does not need to set features and set
mem table since they do not change. QEMU will send messages containing
size, base, addr, kickfd and callfd of the virtqueue in order.
Specifically, the host kernel will receive these messages in order:
    a. VHOST_SET_VRING_NUM
    b. VHOST_SET_VRING_BASE
    c. VHOST_SET_VRING_ADDR
    d. VHOST_SET_VRING_KICK
    e. VHOST_SET_VRING_CALL
    f. VHOST_NET_SET_BACKEND
Finally, after we use set_backend to attach the virtqueue, the virtqueue
will be enabled and start to work.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Message-Id: <20220825085610.80315-1-kangjie.xu@linux.alibaba.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
2023-02-20 19:26:59 -05:00
..
iotlb.c vhost_iotlb: split out IOTLB initialization 2022-05-31 12:44:28 -04:00
Kconfig vhost_vdpa: implement IRQ offloading in vhost_vdpa 2020-08-05 11:08:42 -04:00
Makefile vhost: introduce vDPA-based backend 2020-04-02 10:41:40 -04:00
net.c vhost-net: support VIRTIO_F_RING_RESET 2023-02-20 19:26:59 -05:00
scsi.c vhost-scsi: convert sysfs snprintf and sprintf to sysfs_emit 2023-02-20 19:26:58 -05:00
test.c vhost-test: remove meaningless debug info 2023-02-20 19:26:58 -05:00
test.h tools/virtio: Add --reset 2020-06-22 12:34:21 -04:00
vdpa.c vhost-vdpa: uAPI to resume the device 2023-02-20 19:26:56 -05:00
vhost.c vhost: remove unused paramete 2023-02-20 19:26:58 -05:00
vhost.h vhost: remove unused paramete 2023-02-20 19:26:58 -05:00
vringh.c vringh: fix range used in iotlb_translate() 2022-12-28 05:28:10 -05:00
vsock.c vhost: remove unused paramete 2023-02-20 19:26:58 -05:00