[PATCH v2] vhost-user: Implement an empty VHOST_USER_SEND_RARP command

[PATCH v2] vhost-user: Implement an empty VHOST_USER_SEND_RARP command

[Laurent Vivier]

Passt cannot manage and doesn't need to manage the broadcast of a fake RARP,
but QEMU will report an error message if Passt doesn't implement it.

Implement an empty SEND_RARP command to silence QEMU error message.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 vhost_user.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/vhost_user.c b/vhost_user.c
index f12dec5ddc58..6bf0dda84d90 100644
--- a/vhost_user.c
+++ b/vhost_user.c
@@ -914,7 +914,8 @@ static bool vu_get_protocol_features_exec(struct vu_dev *vdev,
 {
 	uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |
 			    1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
-			    1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE;
+			    1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE |
+			    1ULL << VHOST_USER_PROTOCOL_F_RARP;
 
 	(void)vdev;
 	vmsg_set_reply_u64(msg, features);
@@ -981,6 +982,32 @@ static bool vu_set_vring_enable_exec(struct vu_dev *vdev,
 	return false;
 }
 
+/**
+ * vu_set_send_rarp_exec() - vhost-user specification says: "Broadcast a fake
+ * 			     RARP to notify the migration is terminated",
+ * 			     but passt doesn't need to update any ARP table,
+ * 			     so do nothing to silence QEMU bogus error message
+ * @vdev:	vhost-user device
+ * @vmsg:	vhost-user message
+ *
+ * Return: False as no reply is requested
+ */
+static bool vu_send_rarp_exec(struct vu_dev *vdev,
+			      struct vhost_user_msg *msg)
+{
+	char macstr[ETH_ADDRSTRLEN];
+
+	(void)vdev;
+
+	/* ignore the command */
+
+	debug("Ignore command VHOST_USER_SEND_RARP for %s",
+	      eth_ntop((unsigned char *)&msg->payload.u64, macstr,
+		       sizeof(macstr)));
+
+	return false;
+}
+
 /**
  * vu_set_migration_watch() - Add the migration file descriptor to epoll
  * @vdev:	vhost-user device
@@ -1177,6 +1204,7 @@ static bool (*vu_handle[VHOST_USER_MAX])(struct vu_dev *vdev,
 	[VHOST_USER_SET_VRING_CALL]	   = vu_set_vring_call_exec,
 	[VHOST_USER_SET_VRING_ERR]	   = vu_set_vring_err_exec,
 	[VHOST_USER_SET_VRING_ENABLE]	   = vu_set_vring_enable_exec,
+	[VHOST_USER_SEND_RARP]		   = vu_send_rarp_exec,
 	[VHOST_USER_SET_DEVICE_STATE_FD]   = vu_set_device_state_fd_exec,
 	[VHOST_USER_CHECK_DEVICE_STATE]    = vu_check_device_state_exec,
 };
-- 
@@ -914,7 +914,8 @@ static bool vu_get_protocol_features_exec(struct vu_dev *vdev,
 {
 	uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK |
 			    1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
-			    1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE;
+			    1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE |
+			    1ULL << VHOST_USER_PROTOCOL_F_RARP;
 
 	(void)vdev;
 	vmsg_set_reply_u64(msg, features);
@@ -981,6 +982,32 @@ static bool vu_set_vring_enable_exec(struct vu_dev *vdev,
 	return false;
 }
 
+/**
+ * vu_set_send_rarp_exec() - vhost-user specification says: "Broadcast a fake
+ * 			     RARP to notify the migration is terminated",
+ * 			     but passt doesn't need to update any ARP table,
+ * 			     so do nothing to silence QEMU bogus error message
+ * @vdev:	vhost-user device
+ * @vmsg:	vhost-user message
+ *
+ * Return: False as no reply is requested
+ */
+static bool vu_send_rarp_exec(struct vu_dev *vdev,
+			      struct vhost_user_msg *msg)
+{
+	char macstr[ETH_ADDRSTRLEN];
+
+	(void)vdev;
+
+	/* ignore the command */
+
+	debug("Ignore command VHOST_USER_SEND_RARP for %s",
+	      eth_ntop((unsigned char *)&msg->payload.u64, macstr,
+		       sizeof(macstr)));
+
+	return false;
+}
+
 /**
  * vu_set_migration_watch() - Add the migration file descriptor to epoll
  * @vdev:	vhost-user device
@@ -1177,6 +1204,7 @@ static bool (*vu_handle[VHOST_USER_MAX])(struct vu_dev *vdev,
 	[VHOST_USER_SET_VRING_CALL]	   = vu_set_vring_call_exec,
 	[VHOST_USER_SET_VRING_ERR]	   = vu_set_vring_err_exec,
 	[VHOST_USER_SET_VRING_ENABLE]	   = vu_set_vring_enable_exec,
+	[VHOST_USER_SEND_RARP]		   = vu_send_rarp_exec,
 	[VHOST_USER_SET_DEVICE_STATE_FD]   = vu_set_device_state_fd_exec,
 	[VHOST_USER_CHECK_DEVICE_STATE]    = vu_check_device_state_exec,
 };
-- 
2.48.1

Re: [PATCH v2] vhost-user: Implement an empty VHOST_USER_SEND_RARP command

[Stefano Brivio]

On Fri, 24 Jan 2025 20:07:41 +0100
Laurent Vivier <lvivier@redhat.com> wrote:

> Passt cannot manage and doesn't need to manage the broadcast of a fake RARP,
> but QEMU will report an error message if Passt doesn't implement it.
> 
> Implement an empty SEND_RARP command to silence QEMU error message.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Applied.

-- 
Stefano