virtio/user: support protocol features

rte_vhost doesn't respect those, but any other
implementation should.

Change-Id: Id0a0fa031b7c6e9d572cdffeeb3a1e40d824826d
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/417456
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>

include/spdk_internal/virtio.h

@@ -48,6 +48,10 @@
 #include "spdk/pci_ids.h"
 #include "spdk/env.h"
 
+#ifndef VHOST_USER_F_PROTOCOL_FEATURES
+#define VHOST_USER_F_PROTOCOL_FEATURES	30
+#endif
+
 /**
  * The maximum virtqueue size is 2^15. Use that value as the end of
  * descriptor chain terminator since it will never be a valid index

lib/bdev/virtio/bdev_virtio_blk.c

@@ -80,7 +80,8 @@ struct bdev_virtio_blk_io_channel {
 	 1ULL << VIRTIO_BLK_F_TOPOLOGY		|	\
 	 1ULL << VIRTIO_BLK_F_MQ		|	\
 	 1ULL << VIRTIO_BLK_F_RO		|	\
-	 1ULL << VIRTIO_RING_F_EVENT_IDX)
+	 1ULL << VIRTIO_RING_F_EVENT_IDX	|	\
+	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
 
 static int bdev_virtio_initialize(void);
 static int bdev_virtio_blk_get_ctx_size(void);

lib/bdev/virtio/bdev_virtio_scsi.c

@@ -193,7 +193,8 @@ static bool g_bdev_virtio_finish = false;
 #define VIRTIO_SCSI_DEV_SUPPORTED_FEATURES		\
 	(1ULL << VIRTIO_SCSI_F_INOUT		|	\
 	 1ULL << VIRTIO_SCSI_F_HOTPLUG		|	\
-	 1ULL << VIRTIO_RING_F_EVENT_IDX)
+	 1ULL << VIRTIO_RING_F_EVENT_IDX	|	\
+	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
 
 static void virtio_scsi_dev_unregister_cb(void *io_device);
 static void virtio_scsi_dev_remove(struct virtio_scsi_dev *svdev,

lib/virtio/virtio_user.c

@@ -46,6 +46,9 @@
 
 #include "spdk_internal/virtio.h"
 
+#define VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES \
+	(0)
+
 static int
 virtio_user_create_queue(struct virtio_dev *vdev, uint32_t queue_sel)
 {
@@ -286,6 +289,7 @@ static int
 virtio_user_set_features(struct virtio_dev *vdev, uint64_t features)
 {
 	struct virtio_user_dev *dev = vdev->ctx;
+	uint64_t protocol_features;
 	int ret;
 
 	ret = dev->ops->send_request(dev, VHOST_USER_SET_FEATURES, &features);
@@ -296,6 +300,23 @@ virtio_user_set_features(struct virtio_dev *vdev, uint64_t features)
 	vdev->negotiated_features = features;
 	vdev->modern = virtio_dev_has_feature(vdev, VIRTIO_F_VERSION_1);
 
+	if (!virtio_dev_has_feature(vdev, VHOST_USER_F_PROTOCOL_FEATURES)) {
+		/* nothing else to do */
+		return 0;
+	}
+
+	ret = dev->ops->send_request(dev, VHOST_USER_GET_PROTOCOL_FEATURES, &protocol_features);
+	if (ret < 0) {
+		return -1;
+	}
+
+	protocol_features &= VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES;
+	ret = dev->ops->send_request(dev, VHOST_USER_SET_PROTOCOL_FEATURES, &protocol_features);
+	if (ret < 0) {
+		return -1;
+	}
+
+	dev->protocol_features = protocol_features;
 	return 0;
 }
 
@@ -312,6 +333,7 @@ static int
 virtio_user_setup_queue(struct virtio_dev *vdev, struct virtqueue *vq)
 {
 	struct virtio_user_dev *dev = vdev->ctx;
+	struct vhost_vring_state state;
 	uint16_t queue_idx = vq->vq_queue_index;
 	uint64_t desc_addr, avail_addr, used_addr;
 	int callfd;
@@ -339,6 +361,16 @@ virtio_user_setup_queue(struct virtio_dev *vdev, struct virtqueue *vq)
 		return -1;
 	}
 
+	state.index = vq->vq_queue_index;
+	state.num = 0;
+
+	if (virtio_dev_has_feature(vdev, VHOST_USER_F_PROTOCOL_FEATURES) &&
+	    dev->ops->send_request(dev, VHOST_USER_SET_VRING_ENABLE, &state) < 0) {
+		SPDK_ERRLOG("failed to send VHOST_USER_SET_VRING_ENABLE: %s\n",
+			    spdk_strerror(errno));
+		return -1;
+	}
+
 	dev->callfds[queue_idx] = callfd;
 	dev->kickfds[queue_idx] = kickfd;
 

lib/virtio/virtio_user/vhost.h

@@ -79,6 +79,7 @@ struct virtio_user_dev {
 
 	uint8_t		status;
 	char		path[PATH_MAX];
+	uint64_t	protocol_features;
 	struct vring	vrings[SPDK_VIRTIO_MAX_VIRTQUEUES];
 	struct virtio_user_backend_ops *ops;
 };

lib/virtio/virtio_user/vhost_user.c

@@ -314,12 +314,14 @@ vhost_user_sock(struct virtio_user_dev *dev,
 
 	switch (req) {
 	case VHOST_USER_GET_FEATURES:
+	case VHOST_USER_GET_PROTOCOL_FEATURES:
 	case VHOST_USER_GET_QUEUE_NUM:
 		need_reply = 1;
 		break;
 
 	case VHOST_USER_SET_FEATURES:
 	case VHOST_USER_SET_LOG_BASE:
+	case VHOST_USER_SET_PROTOCOL_FEATURES:
 		msg.payload.u64 = *((__u64 *)arg);
 		msg.size = sizeof(msg.payload.u64);
 		break;
@@ -414,6 +416,7 @@ vhost_user_sock(struct virtio_user_dev *dev,
 
 		switch (req) {
 		case VHOST_USER_GET_FEATURES:
+		case VHOST_USER_GET_PROTOCOL_FEATURES:
 		case VHOST_USER_GET_QUEUE_NUM:
 			if (msg.size != sizeof(msg.payload.u64)) {
 				SPDK_WARNLOG("Received bad msg size\n");