vhost: support MTU protocol feature

This patch implements the vhost-user MTU protocol feature support.
When VIRTIO_NET_F_MTU is negotiated, QEMU notifies the vhost-user
backend with the configured MTU if dedicated protocol feature is
supported.

The value can be used by the application to ensure consistency with
value set by the user.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 5c94322..02a05f9 100644 (file)
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -160,6 +160,7 @@ struct virtio_net {
        uint64_t                log_base;
        uint64_t                log_addr;
        struct ether_addr       mac;
+       uint16_t                mtu;
 
        uint32_t                nr_guest_pages;
        uint32_t                max_guest_pages;

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 2767cca..640661b 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -51,6 +51,9 @@
 #include "vhost.h"
 #include "vhost_user.h"
 
+#define VIRTIO_MIN_MTU 68
+#define VIRTIO_MAX_MTU 65535
+
 static const char *vhost_message_str[VHOST_USER_MAX] = {
        [VHOST_USER_NONE] = "VHOST_USER_NONE",
        [VHOST_USER_GET_FEATURES] = "VHOST_USER_GET_FEATURES",
@@ -72,6 +75,7 @@ static const char *vhost_message_str[VHOST_USER_MAX] = {
        [VHOST_USER_GET_QUEUE_NUM]  = "VHOST_USER_GET_QUEUE_NUM",
        [VHOST_USER_SET_VRING_ENABLE]  = "VHOST_USER_SET_VRING_ENABLE",
        [VHOST_USER_SEND_RARP]  = "VHOST_USER_SEND_RARP",
+       [VHOST_USER_NET_SET_MTU]  = "VHOST_USER_NET_SET_MTU",
 };
 
 static uint64_t
@@ -852,6 +856,22 @@ vhost_user_send_rarp(struct virtio_net *dev, struct VhostUserMsg *msg)
        return 0;
 }
 
+static int
+vhost_user_net_set_mtu(struct virtio_net *dev, struct VhostUserMsg *msg)
+{
+       if (msg->payload.u64 < VIRTIO_MIN_MTU ||
+                       msg->payload.u64 > VIRTIO_MAX_MTU) {
+               RTE_LOG(ERR, VHOST_CONFIG, "Invalid MTU size (%"PRIu64")\n",
+                               msg->payload.u64);
+
+               return -1;
+       }
+
+       dev->mtu = msg->payload.u64;
+
+       return 0;
+}
+
 /* return bytes# of read on success or negative val on failure. */
 static int
 read_vhost_message(int sockfd, struct VhostUserMsg *msg)
@@ -1062,6 +1082,10 @@ vhost_user_msg_handler(int vid, int fd)
                vhost_user_send_rarp(dev, &msg);
                break;
 
+       case VHOST_USER_NET_SET_MTU:
+               ret = vhost_user_net_set_mtu(dev, &msg);
+               break;
+
        default:
                ret = -1;
                break;

diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
index 179e441..838dec8 100644 (file)
--- a/lib/librte_vhost/vhost_user.h
+++ b/lib/librte_vhost/vhost_user.h
@@ -47,11 +47,13 @@
 #define VHOST_USER_PROTOCOL_F_LOG_SHMFD        1
 #define VHOST_USER_PROTOCOL_F_RARP     2
 #define VHOST_USER_PROTOCOL_F_REPLY_ACK        3
+#define VHOST_USER_PROTOCOL_F_NET_MTU 4
 
 #define VHOST_USER_PROTOCOL_FEATURES   ((1ULL << VHOST_USER_PROTOCOL_F_MQ) | \
                                         (1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD) |\
                                         (1ULL << VHOST_USER_PROTOCOL_F_RARP) | \
-                                        (1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK))
+                                        (1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK) | \
+                                        (1ULL << VHOST_USER_PROTOCOL_F_NET_MTU))
 
 typedef enum VhostUserRequest {
        VHOST_USER_NONE = 0,
@@ -74,6 +76,7 @@ typedef enum VhostUserRequest {
        VHOST_USER_GET_QUEUE_NUM = 17,
        VHOST_USER_SET_VRING_ENABLE = 18,
        VHOST_USER_SEND_RARP = 19,
+       VHOST_USER_NET_SET_MTU = 20,
        VHOST_USER_MAX
 } VhostUserRequest;