linux/include
Oleksandr Tyshchenko 9dd060afe2 xen/balloon: Bring alloc(free)_xenballooned_pages helpers back
This patch rolls back some of the changes introduced by commit
121f2faca2 "xen/balloon: rename alloc/free_xenballooned_pages"
in order to make possible to still allocate xenballooned pages
if CONFIG_XEN_UNPOPULATED_ALLOC is enabled.

On Arm the unpopulated pages will be allocated on top of extended
regions provided by Xen via device-tree (the subsequent patches
will add required bits to support unpopulated-alloc feature on Arm).
The problem is that extended regions feature has been introduced
into Xen quite recently (during 4.16 release cycle). So this
effectively means that Linux must only use unpopulated-alloc on Arm
if it is running on "new Xen" which advertises these regions.
But, it will only be known after parsing the "hypervisor" node
at boot time, so before doing that we cannot assume anything.

In order to keep working if CONFIG_XEN_UNPOPULATED_ALLOC is enabled
and the extended regions are not advertised (Linux is running on
"old Xen", etc) we need the fallback to alloc_xenballooned_pages().

This way we wouldn't reduce the amount of memory usable (wasting
RAM pages) for any of the external mappings anymore (and eliminate
XSA-300) with "new Xen", but would be still functional ballooning
out RAM pages with "old Xen".

Also rename alloc(free)_xenballooned_pages to xen_alloc(free)_ballooned_pages
and make xen_alloc(free)_unpopulated_pages static inline in xen.h
if CONFIG_XEN_UNPOPULATED_ALLOC is disabled.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/1639080336-26573-4-git-send-email-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
2022-01-06 09:53:35 +01:00
..
acpi Merge branches 'acpica', 'acpi-ec', 'acpi-pmic' and 'acpi-video' 2021-11-10 14:03:14 +01:00
asm-generic Add linux/cacheflush.h 2021-11-17 10:36:15 -05:00
clocksource
crypto
drm Removed the TTM Huge Page functionnality to address a crash, a timeout 2021-11-11 08:14:19 +10:00
dt-bindings dt-bindings: Rename Ingenic CGU headers to ingenic,*.h 2021-11-11 22:27:14 -06:00
keys
kunit include/kunit/test.h: replace kernel.h with the necessary inclusions 2021-11-09 10:02:49 -08:00
kvm
linux mm: vmscan: Reduce throttling due to a failure to make progress 2021-12-31 11:17:07 -08:00
math-emu
media Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
memory
misc
net sctp: use call_rcu to free endpoint 2021-12-25 17:13:37 +00:00
pcmcia
ras
rdma RDMA/netlink: Add __maybe_unused to static inline in C file 2021-11-16 13:13:08 -04:00
scsi SCSI misc on 20211112 2021-11-12 12:25:50 -08:00
soc net: mscc: ocelot: create a function that replaces an existing VCAP filter 2021-11-26 11:38:20 -08:00
sound ASoC: Fixes for v5.16 2021-11-25 14:35:24 +01:00
target
trace mm: vmscan: Reduce throttling due to a failure to make progress 2021-12-31 11:17:07 -08:00
uapi Networking fixes for 5.16-rc8, including fixes from.. Santa? 2021-12-30 11:12:12 -08:00
vdso
video
xen xen/balloon: Bring alloc(free)_xenballooned_pages helpers back 2022-01-06 09:53:35 +01:00