Re: [Libvir] Proposed remote protocol (XDR source file qemud/remote_protocol.x)

On Mon, Apr 30, 2007 at 06:42:01PM +0100, Richard W.M. Jones wrote: > Attached are the args (*_args) and return structures (*_ret) for all the > calls covered by the remote protocol, that is to say everything except > Save, Restore and CoreDump (see previous email). > > The only problem area are the upper limits imposed on the lengths of > various strings and arrays. The upper limits seem to be required for > safely decoding messages from untrusted sources. Some of them however > would impose limits on such things as the number of CPUs supported, and > perhaps those limits are too low (or too high)? I don't really have any > experience of the sort of huge machines that people might be running > libvirt on. SGI did a preso at the Xen summit about their 1024 CPU monster ia64 box. So given that such a thing already exists, we need biggger to account for future developments. One thing I'm not clear - are these limits actually applied at the protocol level, or is the protocol completely variable length and these limits enforced during decoding ? If the latter, then this isn't so critical to get perfect, because we can do updates without breaking back-compat.