[libvirt] Exposing mem-path in domain XML

Daniel P. Berrange berrange at redhat.com
Thu Jul 27 13:50:25 UTC 2017

On Thu, Jul 27, 2017 at 02:11:25PM +0200, Michal Privoznik wrote:
> Dear list,
> there is the following bug [1] which I'm not quite sure how to grasp. So
> there is this application/infrastructure called Kove [2] that allows you
> to have memory for your application stored on a distant host in network
> and basically fetch needed region on pagefault. Now imagine that
> somebody wants to use it for backing up domain memory. However, the way
> that the tool works is it has some kernel module and then some userland
> binary that is fed with the path of the mmaped file. I don't know all
> the details, but the point is, in order to let users use this we need to
> expose the paths for mem-path for the guest memory. I know we did not
> want to do this in the past, but now it looks like we don't have a way
> around it, do we?

We don't want to expose the concept of paths in the XML because this is
a linux specific way to configure hugepages / shared memory. So we hide
the particular path used in the internal impl of the QEMU driver, and
or via the qemu.conf global config file. I don't really want to change
that approach, particularly if the only reason is to integrate with a
closed source binary like Kove. 

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