Messages in this thread Patch in this message | | | From | Cindy Lu <> | Subject | [PATCH v2 5/5] Documentation: Add reconnect process for VDUSE | Date | Tue, 21 Nov 2023 15:30:50 +0800 |
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Add the document to explained how the reconnect process include how the Userspace App need to do and how it works with kernel
Signed-off-by: Cindy Lu <lulu@redhat.com> --- Documentation/userspace-api/vduse.rst | 29 +++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/Documentation/userspace-api/vduse.rst b/Documentation/userspace-api/vduse.rst index bdb880e01132..6e01c21d94df 100644 --- a/Documentation/userspace-api/vduse.rst +++ b/Documentation/userspace-api/vduse.rst @@ -231,3 +231,32 @@ able to start the dataplane processing as follows: after the used ring is filled. For more details on the uAPI, please see include/uapi/linux/vduse.h. + +HOW VDUSE devices reconnectoin works +---------------- +0. Userspace APP checks if the device /dev/vduse/vduse_name exists, if not create + the device. If yes means this is reconnect, goto 3 + +1. Create a new VDUSE instance with ioctl(VDUSE_CREATE_DEV) on + /dev/vduse/control. + +2. In ioctl(VDUSE_CREATE_DEV), the kernel alloc the memory to sync the reconnect + information. + +3. Userspace App will mmap the pages to userspace + + If this first time to connect, userspace App need save the reconnect + information (struct vhost_reconnect_data) in mapped pages + + If this is reconnect, userspace App need to check if the saved information + OK to reconnect, Also userspace App MUST set the bit reconnected in + struct vhost_reconnect_data to 1. (kernel will use this bit to identify if the + userAPP is reconnected ) + +4. Successfully start the userspace App. + userspace APP need to call ioctl VDUSE_VQ_GET_INFO to sync the vq information. also + APP need to save the reconnect information (struct vhost_reconnect_vring) + while running + +5. When the Userspace App exit, Userspace App need to unmap all the reconnect + pages -- 2.34.3
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