On 29/11/16 23:34, Stefano Stabellini wrote: > > The producer (the backend for **in**, the frontend for **out**) writes to the > array in the following way: > - read memory barrier > - read *cons*, *prod* from shared memory > - write to array at position *prod* up to *cons*, wrapping around the circular > buffer when necessary - write memory barrier > - increase *prod* > - notify the other end via evtchn > > The consumer (the backend for **out**, the frontend for **in**) reads from the > array in the following way:
- read memory barrier > - read *prod*, *cons* from shared memory > - read from array at position *cons* up to *prod*, wrapping around the > circular > buffer when necessary > - memory barrier > - increase *cons* > - notify the other end via evtchn Your barriers are wrong (see corrections above). I think you should use a private copy of cons/prod in the consumer/producer and use this to validate that the shared prod/cons is within a sensible range. You're missing a mechanism to omit unnecessary evtchn notifications (like the standard ring protocol has). This all looks like a generic "transfer byte stream" mechanism which could be usefully made generic and not specific to 9pfs. David _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
