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313389be06
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.