From 749a3db4714db0cccc49dde7b9fb216b924e0bd6 Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Fri, 13 Dec 2024 15:15:20 +0100
Subject: vhost-user: add VHOST_USER_SET_LOG_FD command
VHOST_USER_SET_LOG_FD is an optional message with an eventfd
in ancillary data, it may be used to inform the front-end that the
log has been modified.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
vhost_user.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
vhost_user.h | 1 +
virtio.h | 2 ++
3 files changed, 59 insertions(+)
diff --git a/vhost_user.c b/vhost_user.c
index 48226a8..ce4373d 100644
--- a/vhost_user.c
+++ b/vhost_user.c
@@ -504,6 +504,57 @@ static bool vu_set_mem_table_exec(struct vu_dev *vdev,
return false;
}
+/**
+ * vu_close_log() - Close the logging file descriptor
+ * @vdev: vhost-user device
+ */
+static void vu_close_log(struct vu_dev *vdev)
+{
+ if (vdev->log_call_fd != -1) {
+ close(vdev->log_call_fd);
+ vdev->log_call_fd = -1;
+ }
+}
+
+/**
+ * vu_log_kick() - Inform the front-end that the log has been modified
+ * @vdev: vhost-user device
+ */
+/* cppcheck-suppress unusedFunction */
+void vu_log_kick(const struct vu_dev *vdev)
+{
+ if (vdev->log_call_fd != -1) {
+ int rc;
+
+ rc = eventfd_write(vdev->log_call_fd, 1);
+ if (rc == -1)
+ die_perror("vhost-user kick eventfd_write()");
+ }
+}
+
+/**
+ * vu_set_log_fd_exec() -- Set the eventfd used to report logging update
+ * @vdev: vhost-user device
+ * @vmsg: vhost-user message
+ *
+ * Return: False as no reply is requested
+ */
+static bool vu_set_log_fd_exec(struct vu_dev *vdev,
+ struct vhost_user_msg *msg)
+{
+ if (msg->fd_num != 1)
+ die("Invalid log_fd message");
+
+ if (vdev->log_call_fd != -1)
+ close(vdev->log_call_fd);
+
+ vdev->log_call_fd = msg->fds[0];
+
+ debug("Got log_call_fd: %d", vdev->log_call_fd);
+
+ return false;
+}
+
/**
* vu_set_vring_num_exec() - Set the size of the queue (vring size)
* @vdev: vhost-user device
@@ -864,8 +915,10 @@ void vu_init(struct ctx *c)
.notification = true,
};
}
+ c->vdev->log_call_fd = -1;
}
+
/**
* vu_cleanup() - Reset vhost-user device
* @vdev: vhost-user device
@@ -909,6 +962,8 @@ void vu_cleanup(struct vu_dev *vdev)
}
}
vdev->nregions = 0;
+
+ vu_close_log(vdev);
}
/**
@@ -929,6 +984,7 @@ static bool (*vu_handle[VHOST_USER_MAX])(struct vu_dev *vdev,
[VHOST_USER_GET_QUEUE_NUM] = vu_get_queue_num_exec,
[VHOST_USER_SET_OWNER] = vu_set_owner_exec,
[VHOST_USER_SET_MEM_TABLE] = vu_set_mem_table_exec,
+ [VHOST_USER_SET_LOG_FD] = vu_set_log_fd_exec,
[VHOST_USER_SET_VRING_NUM] = vu_set_vring_num_exec,
[VHOST_USER_SET_VRING_ADDR] = vu_set_vring_addr_exec,
[VHOST_USER_SET_VRING_BASE] = vu_set_vring_base_exec,
diff --git a/vhost_user.h b/vhost_user.h
index fbacb55..2fc0342 100644
--- a/vhost_user.h
+++ b/vhost_user.h
@@ -240,5 +240,6 @@ static inline bool vu_queue_started(const struct vu_virtq *vq)
void vu_print_capabilities(void);
void vu_init(struct ctx *c);
void vu_cleanup(struct vu_dev *vdev);
+void vu_log_kick(const struct vu_dev *vdev);
void vu_control_handler(struct vu_dev *vdev, int fd, uint32_t events);
#endif /* VHOST_USER_H */
diff --git a/virtio.h b/virtio.h
index 0af259d..3b0df34 100644
--- a/virtio.h
+++ b/virtio.h
@@ -103,6 +103,7 @@ struct vu_dev_region {
* @regions: Guest shared memory regions
* @features: Vhost-user features
* @protocol_features: Vhost-user protocol features
+ * @log_call_fd: Eventfd to report logging update
*/
struct vu_dev {
struct ctx *context;
@@ -111,6 +112,7 @@ struct vu_dev {
struct vu_virtq vq[VHOST_USER_MAX_QUEUES];
uint64_t features;
uint64_t protocol_features;
+ int log_call_fd;
};
/**
--
cgit v1.2.3