From 313389be06ff60b4ad23bdb4ff24a12e7c47cb26 Mon Sep 17 00:00:00 2001 From: Kangjie Xu Date: Thu, 25 Aug 2022 16:56:10 +0800 Subject: 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 Signed-off-by: Xuan Zhuo Message-Id: <20220825085610.80315-1-kangjie.xu@linux.alibaba.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang --- 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 383f8f2ae131..07181cd8d52e 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 { -- cgit v1.2.3-59-g8ed1b