On Mon, 5 Sep 2022 16:32:19 +0800, Jason Wang <jasowang at redhat.com>
wrote:>
> ? 2022/8/25 16:56, Kangjie Xu ??:
> > 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 at linux.alibaba.com>
> > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
>
>
> Acked-by: Jason Wang <jasowang at redhat.com>
@mst
Do we miss this?
Thanks.
>
>
> > ---
> >
> > Test environment and method:
> > Host: 5.19.0-rc3
> > Qemu: QEMU emulator version 7.0.50 (With vq rset support)
> > Guest: 5.19.0-rc3 (With vq reset support)
> > Test Cmd: ethtool -g eth1; ethtool -G eth1 rx $1 tx $2; ethtool
-g eth1;
> >
> > The drvier can resize the virtio queue, then virtio queue reset
function should
> > be triggered.
> >
> > The default is split mode, modify Qemu virtio-net to add PACKED
feature to
> > test packed mode.
> >
> > Guest Kernel Patch:
> > https://lore.kernel.org/bpf/20220801063902.129329-1-xuanzhuo at
linux.alibaba.com/
> >
> > QEMU Patch:
> >
https://lore.kernel.org/qemu-devel/cover.1661414345.git.kangjie.xu at
linux.alibaba.com/
> >
> > Looking forward to your review and comments. Thanks.
> >
> > drivers/vhost/net.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > index 68e4ecd1cc0e..8a34928d4fef 100644
> > --- a/drivers/vhost/net.c
> > +++ b/drivers/vhost/net.c
> > @@ -73,7 +73,8 @@ enum {
> > VHOST_NET_FEATURES = VHOST_FEATURES |
> > (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
> > (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
> > - (1ULL << VIRTIO_F_ACCESS_PLATFORM)
> > + (1ULL << VIRTIO_F_ACCESS_PLATFORM) |
> > + (1ULL << VIRTIO_F_RING_RESET)
> > };
> >
> > enum {
>