[dpdk-dev] [PATCH 21.02 v2 1/2] net/virtio: fix missing backend features negotiation

[Maxime Coquelin <maxime.coquelin@redhat.com>]

This patch adds missing backend features negotiation for
in Vhost-vDPA. Without it, IOTLB messages v2 could be sent
by Virtio-user PMD while not supported by the backend.

Fixes: 6b901437056e ("net/virtio: introduce vhost-vDPA backend")
Cc: stable@dpdk.org

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 drivers/net/virtio/virtio_user/vhost.h           |  4 ++++
 drivers/net/virtio/virtio_user/vhost_vdpa.c      | 14 ++++++++++++++
 drivers/net/virtio/virtio_user/virtio_user_dev.c | 14 ++++++++++----
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/vhost.h b/drivers/net/virtio/virtio_user/vhost.h
index 210a3704e7..c1dcc50b58 100644
--- a/drivers/net/virtio/virtio_user/vhost.h
+++ b/drivers/net/virtio/virtio_user/vhost.h
@@ -86,6 +86,10 @@ enum vhost_user_request {
 	VHOST_USER_MAX
 };
 
+#ifndef VHOST_BACKEND_F_IOTLB_MSG_V2
+#define VHOST_BACKEND_F_IOTLB_MSG_V2 1
+#endif
+
 extern const char * const vhost_msg_strings[VHOST_USER_MAX];
 
 struct vhost_memory_region {
diff --git a/drivers/net/virtio/virtio_user/vhost_vdpa.c b/drivers/net/virtio/virtio_user/vhost_vdpa.c
index c7b9349fc8..b6c81d6f17 100644
--- a/drivers/net/virtio/virtio_user/vhost_vdpa.c
+++ b/drivers/net/virtio/virtio_user/vhost_vdpa.c
@@ -35,6 +35,8 @@
 #define VHOST_VDPA_SET_STATUS _IOW(VHOST_VIRTIO, 0x72, __u8)
 #define VHOST_VDPA_SET_VRING_ENABLE	_IOW(VHOST_VIRTIO, 0x75, \
 					     struct vhost_vring_state)
+#define VHOST_SET_BACKEND_FEATURES _IOW(VHOST_VIRTIO, 0x25, __u64)
+#define VHOST_GET_BACKEND_FEATURES _IOR(VHOST_VIRTIO, 0x26, __u64)
 
 static uint64_t vhost_req_user_to_vdpa[] = {
 	[VHOST_USER_SET_OWNER] = VHOST_SET_OWNER,
@@ -51,6 +53,8 @@ static uint64_t vhost_req_user_to_vdpa[] = {
 	[VHOST_USER_SET_STATUS] = VHOST_VDPA_SET_STATUS,
 	[VHOST_USER_GET_STATUS] = VHOST_VDPA_GET_STATUS,
 	[VHOST_USER_SET_VRING_ENABLE] = VHOST_VDPA_SET_VRING_ENABLE,
+	[VHOST_USER_GET_PROTOCOL_FEATURES] = VHOST_GET_BACKEND_FEATURES,
+	[VHOST_USER_SET_PROTOCOL_FEATURES] = VHOST_SET_BACKEND_FEATURES,
 };
 
 /* no alignment requirement */
@@ -86,6 +90,11 @@ vhost_vdpa_dma_map(struct virtio_user_dev *dev, void *addr,
 {
 	struct vhost_msg msg = {};
 
+	if (!(dev->protocol_features & (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2))) {
+		PMD_DRV_LOG(ERR, "IOTLB_MSG_V2 not supported by the backend.");
+		return -1;
+	}
+
 	msg.type = VHOST_IOTLB_MSG_V2;
 	msg.iotlb.type = VHOST_IOTLB_UPDATE;
 	msg.iotlb.iova = iova;
@@ -108,6 +117,11 @@ vhost_vdpa_dma_unmap(struct virtio_user_dev *dev, __rte_unused void *addr,
 {
 	struct vhost_msg msg = {};
 
+	if (!(dev->protocol_features & (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2))) {
+		PMD_DRV_LOG(ERR, "IOTLB_MSG_V2 not supported by the backend.");
+		return -1;
+	}
+
 	msg.type = VHOST_IOTLB_MSG_V2;
 	msg.iotlb.type = VHOST_IOTLB_INVALIDATE;
 	msg.iotlb.iova = iova;
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 053f0267ca..96bc6b232d 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -439,11 +439,13 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
 	 1ULL << VIRTIO_F_RING_PACKED		|	\
 	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
 
-#define VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES		\
+#define VHOST_USER_SUPPORTED_PROTOCOL_FEATURES		\
 	(1ULL << VHOST_USER_PROTOCOL_F_MQ |		\
 	 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |	\
 	 1ULL << VHOST_USER_PROTOCOL_F_STATUS)
 
+#define VHOST_VDPA_SUPPORTED_PROTOCOL_FEATURES		\
+	(1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
 int
 virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 		     int cq, int queue_size, const char *mac, char **ifname,
@@ -462,9 +464,13 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 	dev->mac_specified = 0;
 	dev->frontend_features = 0;
 	dev->unsupported_features = ~VIRTIO_USER_SUPPORTED_FEATURES;
-	dev->protocol_features = VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES;
 	dev->backend_type = backend_type;
 
+	if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_USER)
+		dev->protocol_features = VHOST_USER_SUPPORTED_PROTOCOL_FEATURES;
+	else if (dev->backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA)
+		dev->protocol_features = VHOST_VDPA_SUPPORTED_PROTOCOL_FEATURES;
+
 	parse_mac(dev, mac);
 
 	if (*ifname) {
@@ -497,8 +503,8 @@ virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
 		}
 
 
-		if (dev->device_features &
-				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES)) {
+		if ((dev->device_features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES) ||
+				dev->backend_type == VIRTIO_USER_BACKEND_VHOST_VDPA)) {
 			if (dev->ops->send_request(dev,
 					VHOST_USER_GET_PROTOCOL_FEATURES,
 					&protocol_features))
-- 
2.26.2