[dpdk-dev] [PATCH v4 2/2] net/virtio: add reply-ack support to Virtio-user

[Adrian Moreno <amorenoz@redhat.com>]

From: Maxime Coquelin <maxime.coquelin@redhat.com>

This patch adds support reply-ack vhost-user protocol
feature, which is for now only used to ensure
VHOST_USER_SET_MEM_TABLE requests are handled by the
slave, but later will be used for VHOST_USER_SET_STATUS.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 drivers/net/virtio/virtio_user/vhost.h        |  6 ++++-
 drivers/net/virtio/virtio_user/vhost_user.c   | 24 ++++++++++++++++---
 .../net/virtio/virtio_user/virtio_user_dev.c  |  3 ++-
 3 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio/virtio_user/vhost.h b/drivers/net/virtio/virtio_user/vhost.h
index 9ace1a90c..260e1c308 100644
--- a/drivers/net/virtio/virtio_user/vhost.h
+++ b/drivers/net/virtio/virtio_user/vhost.h
@@ -50,7 +50,11 @@ struct vhost_vring_addr {
 
 /** Protocol features. */
 #ifndef VHOST_USER_PROTOCOL_F_MQ
-#define VHOST_USER_PROTOCOL_F_MQ	0
+#define VHOST_USER_PROTOCOL_F_MQ 0
+#endif
+
+#ifndef VHOST_USER_PROTOCOL_F_REPLY_ACK
+#define VHOST_USER_PROTOCOL_F_REPLY_ACK 3
 #endif
 
 enum vhost_user_request {
diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
index e33067561..631d0e353 100644
--- a/drivers/net/virtio/virtio_user/vhost_user.c
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -32,6 +32,7 @@ struct vhost_user_msg {
 
 #define VHOST_USER_VERSION_MASK     0x3
 #define VHOST_USER_REPLY_MASK       (0x1 << 2)
+#define VHOST_USER_NEED_REPLY_MASK  (0x1 << 3)
 	uint32_t flags;
 	uint32_t size; /* the following payload size */
 	union {
@@ -253,6 +254,7 @@ vhost_user_sock(struct virtio_user_dev *dev,
 	struct vhost_user_msg msg;
 	struct vhost_vring_file *file = 0;
 	int need_reply = 0;
+	int has_reply_ack;
 	int fds[VHOST_MEMORY_MAX_NREGIONS];
 	int fd_num = 0;
 	int len;
@@ -265,6 +267,9 @@ vhost_user_sock(struct virtio_user_dev *dev,
 	if (dev->is_server && vhostfd < 0)
 		return -1;
 
+	if (dev->protocol_features & (1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK))
+		has_reply_ack = 1;
+
 	msg.request = req;
 	msg.flags = VHOST_USER_VERSION;
 	msg.size = 0;
@@ -293,6 +298,9 @@ vhost_user_sock(struct virtio_user_dev *dev,
 		msg.size = sizeof(m.payload.memory.nregions);
 		msg.size += sizeof(m.payload.memory.padding);
 		msg.size += fd_num * sizeof(struct vhost_memory_region);
+
+		if (has_reply_ack)
+			msg.flags |= VHOST_USER_NEED_REPLY_MASK;
 		break;
 
 	case VHOST_USER_SET_LOG_FD:
@@ -341,7 +349,7 @@ vhost_user_sock(struct virtio_user_dev *dev,
 		return -1;
 	}
 
-	if (need_reply) {
+	if (need_reply || msg.flags & VHOST_USER_NEED_REPLY_MASK) {
 		if (vhost_user_read(vhostfd, &msg) < 0) {
 			PMD_DRV_LOG(ERR, "Received msg failed: %s",
 				    strerror(errno));
@@ -371,8 +379,18 @@ vhost_user_sock(struct virtio_user_dev *dev,
 			       sizeof(struct vhost_vring_state));
 			break;
 		default:
-			PMD_DRV_LOG(ERR, "Received unexpected msg type");
-			return -1;
+			/* Reply-ack handling */
+			if (msg.size != sizeof(m.payload.u64)) {
+				PMD_DRV_LOG(ERR, "Received bad msg size");
+				return -1;
+			}
+
+			if (msg.payload.u64 != 0) {
+				PMD_DRV_LOG(ERR, "Slave replied NACK");
+				return -1;
+			}
+
+			break;
 		}
 	}
 
diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
index 105536d35..0a6991bcc 100644
--- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
+++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
@@ -423,7 +423,8 @@ virtio_user_dev_setup(struct virtio_user_dev *dev)
 	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
 
 #define VIRTIO_USER_SUPPORTED_PROTOCOL_FEATURES		\
-	(1ULL << VHOST_USER_PROTOCOL_F_MQ)
+	(1ULL << VHOST_USER_PROTOCOL_F_MQ |		\
+	 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK)
 
 int
 virtio_user_dev_init(struct virtio_user_dev *dev, char *path, int queues,
-- 
2.26.2