Pull xen updates from Juergen Gross:
"A small series for fixing a problem with Xen PVH guests when running
as backends (e.g. as dom0).
Mapping other guests' memory is now working via ZONE_DEVICE, thus not
requiring to abuse the memory hotplug functionality for that purpose"
* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: add helpers to allocate unpopulated memory
memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
xen/balloon: add header guard