xen: enable BALLOON_MEMORY_HOTPLUG by default

Without it a PVH dom0 is mostly useless, as it would balloon down huge
amounts of RAM in order get physical address space to map foreign
memory and grants, ultimately leading to an out of memory situation.

Such option is also needed for HVM or PVH driver domains, since they
also require mapping grants into physical memory regions.

Suggested-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20200324150015.50496-2-roger.pau@citrix.com
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Roger Pau Monne 2020-03-24 16:00:15 +01:00 committed by Boris Ostrovsky
parent 0df683ff74
commit 2abb65a39b

View file

@ -13,6 +13,7 @@ config XEN_BALLOON
config XEN_BALLOON_MEMORY_HOTPLUG
bool "Memory hotplug support for Xen balloon driver"
depends on XEN_BALLOON && MEMORY_HOTPLUG
default y
help
Memory hotplug support for Xen balloon driver allows expanding memory
available for the system above limit declared at system startup.