[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Xen-devel] Error restoring DomU when using GPLPV

> Could the grant-table/shinfo Xenheap pages be confusing matters I
> The save process may save those pages out - since dom0 can map them it
> also save them - and then they get mistakenly restored as domheap
pages at
> the far end. All would work out okay in the end when you remap those
> pages during GPLPV restore as the domheap pages would get implciitly
> But maybe there is not allocation headroom for the guest in the
meantime so
> the restore fails.
> Just a theory. Maybe you could try unmapping grant/shinfo pages in the
> suspend callback? This may not help for live migration though, where
> get transmitted before the callback. It may be necessary to allow dom0
> specify 'map me a page but not if it's special' and plumb that up to
> xc_domain_save. It'd be good to have the theory proved first.

I took the easier path and told my grant code to map 2 less pages, and
sure enough it tries to allocate 31 pages (which succeeds) but then
tries to allocate 7 (which fails). So the 31 (was 33) must contain the
grant table pages etc. I'll attempt to add the unmap code you requested
and see if it makes a difference...

So why doesn't PV have this problem? Does it not send the pages first?
And do you think that a Linux HVM domain with PV drivers would suffer
the same fate?



Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.