From 8db980965f3d8cde1abbdb89eaecbc829460133e Mon Sep 17 00:00:00 2001

From: Stefan Hajnoczi <stefanha@redhat.com>

Date: Wed, 31 Jan 2018 17:46:50 +0000

Subject: [PATCH 5/6] vhost: add flag for built-in virtio driver

The librte_vhost API is used in two ways:

1. As a vhost net device backend via rte_vhost_enqueue/dequeue_burst().

2. As a library for implementing vhost device backends.

There is no distinction between the two at the API level or in the

librte_vhost implementation.  For example, device state is kept in

"struct virtio_net" regardless of whether this is actually a net device

backend or whether the built-in virtio_net.c driver is in use.

The virtio_net.c driver should be a librte_vhost API client just like

the vhost-scsi code and have no special access to vhost.h internals.

Unfortunately, fixing this requires significant librte_vhost API

changes.

This patch takes a different approach: keep the librte_vhost API

unchanged but track whether the built-in virtio_net.c driver is in use.

See the next patch for a bug fix that requires knowledge of whether

virtio_net.c is in use.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Acked-by: Yuanhan Liu <yliu@fridaylinux.org>

(cherry picked from commit 1c717af4c699e60081feb1d645f86189551f9a9c)

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>

---

 dpdk-17.11/lib/librte_vhost/socket.c     | 15 +++++++++++++++

 dpdk-17.11/lib/librte_vhost/vhost.c      | 17 ++++++++++++++++-

 dpdk-17.11/lib/librte_vhost/vhost.h      |  3 +++

 dpdk-17.11/lib/librte_vhost/virtio_net.c | 14 ++++++++++++++

 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c

index 422da002f..ceecc6149 100644

--- a/lib/librte_vhost/socket.c

+++ b/lib/librte_vhost/socket.c

@@ -69,6 +69,7 @@ struct vhost_user_socket {

 	bool reconnect;

 	bool dequeue_zero_copy;

 	bool iommu_support;

+	bool use_builtin_virtio_net;

 	/*

 	 * The "supported_features" indicates the feature bits the

@@ -224,6 +225,8 @@ vhost_user_add_connection(int fd, struct vhost_user_socket *vsocket)

 	size = strnlen(vsocket->path, PATH_MAX);

 	vhost_set_ifname(vid, vsocket->path, size);

+	vhost_set_builtin_virtio_net(vid, vsocket->use_builtin_virtio_net);

+

 	if (vsocket->dequeue_zero_copy)

 		vhost_enable_dequeue_zero_copy(vid);

@@ -547,6 +550,12 @@ rte_vhost_driver_disable_features(const char *path, uint64_t features)

 	pthread_mutex_lock(&vhost_user.mutex);

 	vsocket = find_vhost_user_socket(path);

+

+	/* Note that use_builtin_virtio_net is not affected by this function

+	 * since callers may want to selectively disable features of the

+	 * built-in vhost net device backend.

+	 */

+

 	if (vsocket)

 		vsocket->features &= ~features;

 	pthread_mutex_unlock(&vhost_user.mutex);

@@ -587,6 +596,11 @@ rte_vhost_driver_set_features(const char *path, uint64_t features)

 	if (vsocket) {

 		vsocket->supported_features = features;

 		vsocket->features = features;

+

+		/* Anyone setting feature bits is implementing their own vhost

+		 * device backend.

+		 */

+		vsocket->use_builtin_virtio_net = false;

 	}

 	pthread_mutex_unlock(&vhost_user.mutex);

@@ -667,6 +681,7 @@ rte_vhost_driver_register(const char *path, uint64_t flags)

 	 * rte_vhost_driver_set_features(), which will overwrite following

 	 * two values.

 	 */

+	vsocket->use_builtin_virtio_net = true;

 	vsocket->supported_features = VIRTIO_NET_SUPPORTED_FEATURES;

 	vsocket->features           = VIRTIO_NET_SUPPORTED_FEATURES;

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c

index df528a4ea..75deaa877 100644

--- a/lib/librte_vhost/vhost.c

+++ b/lib/librte_vhost/vhost.c

@@ -279,7 +279,7 @@ reset_device(struct virtio_net *dev)

 	dev->features = 0;

 	dev->protocol_features = 0;

-	dev->flags = 0;

+	dev->flags &= VIRTIO_DEV_BUILTIN_VIRTIO_NET;

 	for (i = 0; i < dev->nr_vring; i++)

 		reset_vring_queue(dev, i);

@@ -315,6 +315,7 @@ vhost_new_device(void)

 	vhost_devices[i] = dev;

 	dev->vid = i;

+	dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;

 	dev->slave_req_fd = -1;

 	return i;

@@ -371,6 +372,20 @@ vhost_enable_dequeue_zero_copy(int vid)

 	dev->dequeue_zero_copy = 1;

 }

+void

+vhost_set_builtin_virtio_net(int vid, bool enable)

+{

+	struct virtio_net *dev = get_device(vid);

+

+	if (dev == NULL)

+		return;

+

+	if (enable)

+		dev->flags |= VIRTIO_DEV_BUILTIN_VIRTIO_NET;

+	else

+		dev->flags &= ~VIRTIO_DEV_BUILTIN_VIRTIO_NET;

+}

+

 int

 rte_vhost_get_mtu(int vid, uint16_t *mtu)

 {

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h

index 9cad1bb3c..e06531e6b 100644

--- a/lib/librte_vhost/vhost.h

+++ b/lib/librte_vhost/vhost.h

@@ -53,6 +53,8 @@

 #define VIRTIO_DEV_RUNNING 1

 /* Used to indicate that the device is ready to operate */

 #define VIRTIO_DEV_READY 2

+/* Used to indicate that the built-in vhost net device backend is enabled */

+#define VIRTIO_DEV_BUILTIN_VIRTIO_NET 4

 /* Backend value set by guest. */

 #define VIRTIO_DEV_STOPPED -1

@@ -371,6 +373,7 @@ int alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx);

 void vhost_set_ifname(int, const char *if_name, unsigned int if_len);

 void vhost_enable_dequeue_zero_copy(int vid);

+void vhost_set_builtin_virtio_net(int vid, bool enable);

 struct vhost_device_ops const *vhost_driver_callback_get(const char *path);

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c

index 6fee16e55..3bfd71945 100644

--- a/lib/librte_vhost/virtio_net.c

+++ b/lib/librte_vhost/virtio_net.c

@@ -727,6 +727,13 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,

 	if (!dev)

 		return 0;

+	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {

+		RTE_LOG(ERR, VHOST_DATA,

+			"(%d) %s: built-in vhost net backend is disabled.\n",

+			dev->vid, __func__);

+		return 0;

+	}

+

 	if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))

 		return virtio_dev_merge_rx(dev, queue_id, pkts, count);

 	else

@@ -1173,6 +1180,13 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,

 	if (!dev)

 		return 0;

+	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {

+		RTE_LOG(ERR, VHOST_DATA,

+			"(%d) %s: built-in vhost net backend is disabled.\n",

+			dev->vid, __func__);

+		return 0;

+	}

+

 	if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {

 		RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",

 			dev->vid, __func__, queue_id);

-- 

2.14.3