[PATCH 0/4] xen: critical bug fixes for 2.6.39-rc3

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Hi all,
this is a small collection of critical xen bug fixes for 2.6.39-rc3:
the recent changes to the initial kernel pagetable allocation mechanism
(4b239f458c229de044d6905c2b0f9fe16ed9e01e in particular) caused a number
of issues on Xen.
This patch series fixes those issues and it is required just to boot a
2.6.39 linux kernel as regular xen guest.


The list of patches with a diffstat follows:

Stefano Stabellini (4):
      xen: mask_rw_pte mark RO all pagetable pages up to pgt_buf_top
      x86,xen: introduce x86_init.mapping.pagetable_reserve
      xen: more debugging in the e820 parsing
      xen: do not create the extra e820 region at an addr lower than 4G

 arch/x86/include/asm/pgtable_types.h |    1 +
 arch/x86/include/asm/x86_init.h      |    9 +++++++++
 arch/x86/kernel/x86_init.c           |    4 ++++
 arch/x86/mm/init.c                   |    9 +++++++--
 arch/x86/xen/mmu.c                   |   17 ++++++++++++++++-
 arch/x86/xen/setup.c                 |    6 +++++-
 6 files changed, 42 insertions(+), 4 deletions(-)


The first two commits make sure pagetable pages are marked RO while
other pages are marked RW.

The third commit adds a couple of useful debugging statements.

The fourth commit fixes a boot crash on xen when booting as initial
domain: the xen extra memory region shouldn't start below 4G otherwise
e820_end_of_low_ram_pfn() could return an address above 4G. As a
consequence init_memory_mapping would end up mapping MMIO regions
without going through the fixmap.


A git branch with this series is available here:

git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git 2.6.39-rc3-fixes


Comments are welcome.

- Stefano