Messages in this thread Patch in this message | | | From | Cindy Lu <> | Subject | [PATCH v4 5/5] Documentation: Add reconnect process for VDUSE | Date | Wed, 7 Feb 2024 13:43:32 +0800 |
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Add a document explaining the reconnect process, including what the Userspace App needs to do and how it works with the kernel.
Signed-off-by: Cindy Lu <lulu@redhat.com> --- Documentation/userspace-api/vduse.rst | 32 +++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
diff --git a/Documentation/userspace-api/vduse.rst b/Documentation/userspace-api/vduse.rst index bdb880e01132..a2be85e0e516 100644 --- a/Documentation/userspace-api/vduse.rst +++ b/Documentation/userspace-api/vduse.rst @@ -231,3 +231,35 @@ 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 it does not exist, need to create the instance.goto step 1 + If it does exist, it means this is a reconnect and goto step 3. + +1. Create a new VDUSE instance with ioctl(VDUSE_CREATE_DEV) on + /dev/vduse/control. + +2. When the ioctl(VDUSE_CREATE_DEV) function is called, the kernel allocates memory + to save the reconnect information. + +3. Userspace App need to mmap the pages to userspace + Userspace App need to map Pages 0 to vq_number for vq status, + Users can define the structure for saving the reconnect information themselves + in the userspace. + +4. Check if the infomatin sutiable for reconnect + If this is reconnect: + Before attempting to reconnect, The userspace application need to the + ioctl VDUSE_DEV_GET_CONFIG,VDUSE_DEV_GET_STATUS,VDUSE_DEV_GET_FEATURES... + to get the and confirm if these information are suitable for reconnecting. + +5. Start the userspace App. + While running, the application should store the relevant information about + reconnections in mapped pages. + When calling ioctl VDUSE_VQ_GET_INFO from the userspace APP to get vq information, it is necessary + to check if this is a reconnection. If a reconnection has occurred, the vq-related information + must be get from the mapped pages. + +6. When the Userspace App exits, it is necessary to unmap all the reconnect pages. -- 2.43.0
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