[0/2] xen/x86: alternative fix for XSA-369

Message

Roger Pau Monne March 17, 2021, 11:03 a.m. UTC

Hello,

This is a proposal for an alternative fix for XSA-369 that instead of
special casing XEN_UNPOPULATED_ALLOC to size the p2m relies on making
XEN_BALLOON_MEMORY_HOTPLUG_LIMIT depend on the generic MEMORY_HOTPLUG
option rather than XEN_BALLOON_MEMORY_HOTPLUG.

I think this is safer, as we don't want to be special casing any option
that pulls in generic MEMORY_HOTPLUG without XEN_BALLOON_MEMORY_HOTPLUG.
Without this we would also need to at least special case ZONE_DEVICE
which also relies on MEMORY_HOTPLUG, and is what pulls the generic
MEMORY_HOTPLUG option even when XEN_BALLOON_MEMORY_HOTPLUG is disabled
with XEN_UNPOPULATED_ALLOC.

Thanks, Roger.

Roger Pau Monne (2):
  xen/x86: make XEN_BALLOON_MEMORY_HOTPLUG_LIMIT depend on
    MEMORY_HOTPLUG
  Revert "xen: fix p2m size in dom0 for disabled memory hotplug case"

 arch/x86/include/asm/xen/page.h | 12 ------------
 arch/x86/xen/p2m.c              |  7 ++-----
 arch/x86/xen/setup.c            | 25 ++++++++++++++++++++++---
 drivers/xen/Kconfig             |  4 ++--
 4 files changed, 26 insertions(+), 22 deletions(-)