[PATCH v2 00/14] Make PAT handling less brittle

[Demi Marie Obenour <demi@xxxxxxxxxxxxxxxxxxxxxx>]

While working on Qubes OS Marek found out that there were some PAT hacks
in the Linux i195 driver.  I decided to make Xen use Linux’s PAT to see
if it solved the graphics glitches that were observed; it did.  This
required a substantial amount of preliminary work that is useful even
without using Linux’s PAT.

Patches 1 through 13 are the preliminary work and I would like them to
be accepted into upstream Xen.  Patch 13 does break ABI by rejecting the
unused PAT entries, but this will only impact buggy PV guests and can be
disabled with a Xen command-line option.  Patch 14 actually switches to
Linux’s PAT and is NOT intended to be merged (at least for now) as it
would at a minimum break migration of PV guests from hosts that do not
have the patch.

Demi Marie Obenour (14):
  x86/mm: Avoid hard-coding PAT in get_page_from_l1e()
  p2m-pt: Avoid hard-coding Xen's PAT
  x86/mm/shadow: avoid assuming a specific Xen PAT
  efi: Avoid hard-coding the various PAT constants
  x86/mm/shadow: do not open-code PAGE_CACHE_ATTRS
  x86: Add memory type constants
  x86: Replace PAT_* with X86_MT_*
  x86: Replace MTRR_* constants with X86_MT_* constants
  x86: Replace EPT_EMT_* constants with X86_MT_*
  x86: Remove remaining uses of MTRR_* constants
  x86: Derive XEN_MSR_PAT from its individual entries
  x86/mm: make code robust to future PAT changes
  x86/mm: Reject invalid cacheability in PV guests by default
  x86: Use Linux's PAT

 xen/arch/x86/cpu/mtrr/generic.c         |  12 +--
 xen/arch/x86/cpu/mtrr/main.c            |  33 ++++----
 xen/arch/x86/e820.c                     |   4 +-
 xen/arch/x86/hvm/hvm.c                  |  12 +--
 xen/arch/x86/hvm/mtrr.c                 | 102 ++++++++++++------------
 xen/arch/x86/hvm/vmx/vmcs.c             |   2 +-
 xen/arch/x86/hvm/vmx/vmx.c              |  18 ++---
 xen/arch/x86/include/asm/hvm/vmx/vmcs.h |   2 +-
 xen/arch/x86/include/asm/hvm/vmx/vmx.h  |   9 ---
 xen/arch/x86/include/asm/mtrr.h         |  22 +----
 xen/arch/x86/include/asm/page.h         |   4 +-
 xen/arch/x86/include/asm/processor.h    |  15 ++--
 xen/arch/x86/include/asm/x86-defns.h    |  13 +++
 xen/arch/x86/mm.c                       |  80 +++++++++++++++++--
 xen/arch/x86/mm/hap/nested_ept.c        |   4 +-
 xen/arch/x86/mm/p2m-ept.c               |  70 ++++++++--------
 xen/arch/x86/mm/p2m-pt.c                |   6 +-
 xen/arch/x86/mm/shadow/multi.c          |  16 ++--
 xen/common/efi/boot.c                   |  12 +--
 19 files changed, 248 insertions(+), 188 deletions(-)

-- 
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab