Hi Tetsuya: There are two major technical issues in my mind for vhost-user implementation.
1) memory region map Vhost-user passes us file fd and offset for each memory region. Unfortunately the mmap offset is "very" wrong. I discovered this issue long time ago, and also found that I couldn't mmap the huge page file even with correct offset(need double check). Just now I find that people reported this issue on Nov 3. [Qemu-devel] [PULL 27/29] vhost-user: fix mmap offset calculation Anyway, I turned to the same idea used in our DPDK vhost-cuse: only use the fd for region(0) to map the whole file. I think we should use this way temporarily to support qemu-2.1 as it has that bug. 2) what message is the indicator for vhost start/release? Previously for vhost-cuse, it has SET_BACKEND message. What we should do for vhost-user? SET_VRING_KICK for start? What about for release? Unlike the kernel virtio, the DPDK virtio in guest could be restarted. Thoughts? -huawei
