On Wed, Jan 09, 2019 at 07:27:23PM +0800, elohi...@gmail.com wrote: > @@ -382,6 +397,30 @@ If VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD protocol feature > is negotiated, > slave can send file descriptors (at most 8 descriptors in each message) > to master via ancillary data using this fd communication channel. > > +Inflight I/O tracking > +--------------------- > + > +To support slave reconnecting, slave need to track inflight I/O in a > +shared memory. VHOST_USER_GET_INFLIGHT_FD and VHOST_USER_SET_INFLIGHT_FD > +are used to transfer the memory between master and slave. And to encourage > +consistency, we provide a recommended format for this memory:
I think we should make a stronger statement and actually just say what the format is. Not recommend it weakly. > + > +offset width description > +0x0 0x400 region for queue0 > +0x400 0x400 region for queue1 > +0x800 0x400 region for queue2 > +... ... ... > + > +For each virtqueue, we have a 1024 bytes region. Why is the size hardcoded? Why not a function of VQ size? > The region's format is like: > + > +offset width description > +0x0 0x1 descriptor 0 is in use or not > +0x1 0x1 descriptor 1 is in use or not > +0x2 0x1 descriptor 2 is in use or not > +... ... ... > + > +For each descriptor, we use one byte to specify whether it's in use or not. > + > Protocol features > ----------------- > I think that it's a good idea to have a version in this region. Otherwise how are you going to handle compatibility when this needs to be extended?
