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

Daniel P. Berrange wrote:
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.

The latter, so yeah afaics we should be able to increase them later without any harmful effects on ABI compatibility.

I've bumped up some of the limits in response to your comments.


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