[PATCH v2 2/2] vhost: introduce VHOST_USER_RESET_VRING

[Kangjie Xu <kangjie.xu@linux.alibaba.com>]

To support the reset operation for an individual virtqueue, we
introduce a new message VHOST_USER_RESET_VRING. When the feature
VIRTIO_F_RING_RESET feature has been successfully negotiated, This
message is submitted by the front-end to reset an individual
virtqueue to initial states in the back-end. The reply is needed
to ensure that the reset operation is complete.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 lib/vhost/vhost.c      |  2 +-
 lib/vhost/vhost.h      |  1 +
 lib/vhost/vhost_user.c | 27 ++++++++++++++++++++++++++-
 lib/vhost/vhost_user.h |  1 +
 4 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 60cb05a0ff..215a1ca355 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -610,7 +610,7 @@ init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 	vhost_user_iotlb_init(dev, vring_idx);
 }
 
-static void
+void
 reset_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 {
 	struct vhost_virtqueue *vq;
diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index 76461a3406..eccb52842d 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -791,6 +791,7 @@ get_device(int vid)
 
 int vhost_new_device(void);
 void cleanup_device(struct virtio_net *dev, int destroy);
+void reset_vring_queue(struct virtio_net *dev, uint32_t vring_idx);
 void reset_device(struct virtio_net *dev);
 void vhost_destroy_device(int);
 void vhost_destroy_device_notify(struct virtio_net *dev);
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 4ad28bac45..5f7743d9d9 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2771,6 +2771,30 @@ vhost_user_set_status(struct virtio_net **pdev,
 	return RTE_VHOST_MSG_RESULT_OK;
 }
 
+static int
+vhost_user_reset_vring(struct virtio_net **pdev,
+			struct vhu_msg_context *ctx __rte_unused,
+			int main_fd __rte_unused)
+{
+	struct virtio_net *dev = *pdev;
+	int index = (int)ctx->msg.payload.state.index;
+
+	VHOST_LOG_CONFIG(dev->ifname, INFO, "reset queue: queue idx: %d\n", index);
+
+	if (!(dev->features & (1ULL << VIRTIO_F_RING_RESET))) {
+		return RTE_VHOST_MSG_RESULT_ERR;
+	}
+
+	dev->virtqueue[index]->enabled = false;
+	reset_vring_queue(dev, index);
+
+	ctx->msg.payload.state.num = 0;
+	ctx->msg.size = sizeof(ctx->msg.payload.u64);
+	ctx->fd_num = 0;
+
+	return RTE_VHOST_MSG_RESULT_REPLY;
+}
+
 #define VHOST_MESSAGE_HANDLERS \
 VHOST_MESSAGE_HANDLER(VHOST_USER_NONE, NULL, false) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_GET_FEATURES, vhost_user_get_features, false) \
@@ -2803,7 +2827,8 @@ VHOST_MESSAGE_HANDLER(VHOST_USER_POSTCOPY_END, vhost_user_postcopy_end, false) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_GET_INFLIGHT_FD, vhost_user_get_inflight_fd, false) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_INFLIGHT_FD, vhost_user_set_inflight_fd, true) \
 VHOST_MESSAGE_HANDLER(VHOST_USER_SET_STATUS, vhost_user_set_status, false) \
-VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false)
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_STATUS, vhost_user_get_status, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_VRING, vhost_user_reset_vring, false)
 
 #define VHOST_MESSAGE_HANDLER(id, handler, accepts_fd) \
 	[id] = { #id, handler, accepts_fd },
diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h
index 8ecca68597..51cb2fc74a 100644
--- a/lib/vhost/vhost_user.h
+++ b/lib/vhost/vhost_user.h
@@ -60,6 +60,7 @@ typedef enum VhostUserRequest {
 	VHOST_USER_SET_INFLIGHT_FD = 32,
 	VHOST_USER_SET_STATUS = 39,
 	VHOST_USER_GET_STATUS = 40,
+	VHOST_USER_RESET_VRING = 41
 } VhostUserRequest;
 
 typedef enum VhostUserSlaveRequest {
-- 
2.32.0