diff --git a/epoll_type.h b/epoll_type.h
index f3ef415..fd9eac3 100644
--- a/epoll_type.h
+++ b/epoll_type.h
@@ -40,6 +40,8 @@ enum epoll_type {
EPOLL_TYPE_VHOST_CMD,
/* vhost-user kick event socket */
EPOLL_TYPE_VHOST_KICK,
+ /* vhost-user migration socket */
+ EPOLL_TYPE_VHOST_MIGRATION,
EPOLL_NUM_TYPES,
};
diff --git a/passt.c b/passt.c
index 1a0c404..b1c8ab6 100644
--- a/passt.c
+++ b/passt.c
@@ -75,6 +75,7 @@ char *epoll_type_str[] = {
[EPOLL_TYPE_TAP_LISTEN] = "listening qemu socket",
[EPOLL_TYPE_VHOST_CMD] = "vhost-user command socket",
[EPOLL_TYPE_VHOST_KICK] = "vhost-user kick socket",
+ [EPOLL_TYPE_VHOST_MIGRATION] = "vhost-user migration socket",
};
static_assert(ARRAY_SIZE(epoll_type_str) == EPOLL_NUM_TYPES,
"epoll_type_str[] doesn't match enum epoll_type");
@@ -356,6 +357,9 @@ loop:
case EPOLL_TYPE_VHOST_KICK:
vu_kick_cb(c.vdev, ref, &now);
break;
+ case EPOLL_TYPE_VHOST_MIGRATION:
+ vu_migrate(c.vdev, eventmask);
+ break;
default:
/* Can't happen */
ASSERT(0);
diff --git a/vhost_user.c b/vhost_user.c
index 2962709..daff9ab 100644
--- a/vhost_user.c
+++ b/vhost_user.c
@@ -981,7 +981,78 @@ static bool vu_set_vring_enable_exec(struct vu_dev *vdev,
}
/**
- * vu_check_device_state_exec() -- Return device state migration result
+ * vu_set_migration_watch() - Add the migration file descriptor to epoll
+ * @vdev: vhost-user device
+ * @fd: File descriptor to add
+ * @direction: Direction of the migration (save or load backend state)
+ */
+static void vu_set_migration_watch(const struct vu_dev *vdev, int fd,
+ uint32_t direction)
+{
+ union epoll_ref ref = {
+ .type = EPOLL_TYPE_VHOST_MIGRATION,
+ .fd = fd,
+ };
+ struct epoll_event ev = { 0 };
+
+ ev.data.u64 = ref.u64;
+ switch (direction) {
+ case VHOST_USER_TRANSFER_STATE_DIRECTION_SAVE:
+ ev.events = EPOLLOUT;
+ break;
+ case VHOST_USER_TRANSFER_STATE_DIRECTION_LOAD:
+ ev.events = EPOLLIN;
+ break;
+ default:
+ ASSERT(0);
+ }
+
+ epoll_ctl(vdev->context->epollfd, EPOLL_CTL_ADD, ref.fd, &ev);
+}
+
+/**
+ * vu_set_device_state_fd_exec() - Set the device state migration channel
+ * @vdev: vhost-user device
+ * @vmsg: vhost-user message
+ *
+ * Return: True as the reply contains 0 to indicate success
+ * and set bit 8 as we don't provide our own fd.
+ */
+static bool vu_set_device_state_fd_exec(struct vu_dev *vdev,
+ struct vhost_user_msg *msg)
+{
+ unsigned int direction = msg->payload.transfer_state.direction;
+ unsigned int phase = msg->payload.transfer_state.phase;
+
+ if (msg->fd_num != 1)
+ die("Invalid device_state_fd message");
+
+ if (phase != VHOST_USER_TRANSFER_STATE_PHASE_STOPPED)
+ die("Invalid device_state_fd phase: %d", phase);
+
+ if (direction != VHOST_USER_TRANSFER_STATE_DIRECTION_SAVE &&
+ direction != VHOST_USER_TRANSFER_STATE_DIRECTION_LOAD)
+ die("Invalide device_state_fd direction: %d", direction);
+
+ if (vdev->device_state_fd != -1) {
+ vu_remove_watch(vdev, vdev->device_state_fd);
+ close(vdev->device_state_fd);
+ }
+
+ vdev->device_state_fd = msg->fds[0];
+ vdev->device_state_result = -1;
+ vu_set_migration_watch(vdev, vdev->device_state_fd, direction);
+
+ debug("Got device_state_fd: %d", vdev->device_state_fd);
+
+ /* We don't provide a new fd for the data transfer */
+ vmsg_set_reply_u64(msg, VHOST_USER_VRING_NOFD_MASK);
+
+ return true;
+}
+
+/**
+ * vu_check_device_state_exec() - Return device state migration result
* @vdev: vhost-user device
* @vmsg: vhost-user message
*
@@ -1018,6 +1089,7 @@ void vu_init(struct ctx *c)
}
c->vdev->log_table = NULL;
c->vdev->log_call_fd = -1;
+ c->vdev->device_state_fd = -1;
c->vdev->device_state_result = -1;
}
@@ -1068,7 +1140,12 @@ void vu_cleanup(struct vu_dev *vdev)
vu_close_log(vdev);
- vdev->device_state_result = -1;
+ if (vdev->device_state_fd != -1) {
+ vu_remove_watch(vdev, vdev->device_state_fd);
+ close(vdev->device_state_fd);
+ vdev->device_state_fd = -1;
+ vdev->device_state_result = -1;
+ }
}
/**
@@ -1099,6 +1176,7 @@ 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_SET_DEVICE_STATE_FD] = vu_set_device_state_fd_exec,
[VHOST_USER_CHECK_DEVICE_STATE] = vu_check_device_state_exec,
};
diff --git a/virtio.h b/virtio.h
index 512ec1b..7bef2d2 100644
--- a/virtio.h
+++ b/virtio.h
@@ -106,6 +106,7 @@ struct vu_dev_region {
* @log_call_fd: Eventfd to report logging update
* @log_size: Size of the logging memory region
* @log_table: Base of the logging memory region
+ * @device_state_fd: Device state migration channel
* @device_state_result: Device state migration result
*/
struct vu_dev {
@@ -118,6 +119,7 @@ struct vu_dev {
int log_call_fd;
uint64_t log_size;
uint8_t *log_table;
+ int device_state_fd;
int device_state_result;
};
diff --git a/vu_common.c b/vu_common.c
index 0ba2351..87a0d94 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -297,3 +297,52 @@ err:
return -1;
}
+
+/**
+ * vu_migrate() - Send/receive passt insternal state to/from QEMU
+ * @vdev: vhost-user device
+ * @events: epoll events
+ */
+void vu_migrate(struct vu_dev *vdev, uint32_t events)
+{
+ int ret;
+
+ /* TODO: collect/set passt internal state
+ * and use vdev->device_state_fd to send/receive it
+ */
+ debug("vu_migrate fd %d events %x", vdev->device_state_fd, events);
+ if (events & EPOLLOUT) {
+ debug("Saving backend state");
+
+ /* send some stuff */
+ ret = write(vdev->device_state_fd, "PASST", 6);
+ /* value to be returned by VHOST_USER_CHECK_DEVICE_STATE */
+ vdev->device_state_result = ret == -1 ? -1 : 0;
+ /* Closing the file descriptor signals the end of transfer */
+ epoll_ctl(vdev->context->epollfd, EPOLL_CTL_DEL,
+ vdev->device_state_fd, NULL);
+ close(vdev->device_state_fd);
+ vdev->device_state_fd = -1;
+ } else if (events & EPOLLIN) {
+ char buf[6];
+
+ debug("Loading backend state");
+ /* read some stuff */
+ ret = read(vdev->device_state_fd, buf, sizeof(buf));
+ /* value to be returned by VHOST_USER_CHECK_DEVICE_STATE */
+ if (ret != sizeof(buf)) {
+ vdev->device_state_result = -1;
+ } else {
+ ret = strncmp(buf, "PASST", sizeof(buf));
+ vdev->device_state_result = ret == 0 ? 0 : -1;
+ }
+ } else if (events & EPOLLHUP) {
+ debug("Closing migration channel");
+
+ /* The end of file signals the end of the transfer. */
+ epoll_ctl(vdev->context->epollfd, EPOLL_CTL_DEL,
+ vdev->device_state_fd, NULL);
+ close(vdev->device_state_fd);
+ vdev->device_state_fd = -1;
+ }
+}
diff --git a/vu_common.h b/vu_common.h
index bd70faf..d56c021 100644
--- a/vu_common.h
+++ b/vu_common.h
@@ -57,4 +57,5 @@ void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
void vu_kick_cb(struct vu_dev *vdev, union epoll_ref ref,
const struct timespec *now);
int vu_send_single(const struct ctx *c, const void *buf, size_t size);
+void vu_migrate(struct vu_dev *vdev, uint32_t events);
#endif /* VU_COMMON_H */