[PATCH RFC] Remove PV superpage support (v1).

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

Hey,

This patchset removes the opt_allow_superpage parameter and also the code around it.
I've tested (migration, bootup, etc) with normal PV and HVM guests and all works.

I haven't yet tested kernels that had PV superpage support in (UEK2, UEK3, classic
Xen kernels) but looking at the code it ought to just print in the dmesg:

"Xen hypervisor is not configured to allow hugepages"

and fail when setting up hugepages. That will be tested shortly (hence
the RFC nature).

I am hoping the maintainers can guide me in how they would like:
 - Deal with documentation? I removed the allowsuperpage from documentation
   but perhaps it should just mention deprecated?
 - I left put_superpage as put_page_from_l2e calls it - but I can't see
   how the _PAGE_PSE bit would be set as you won't be able to even
   put that bit on (after my patch). Perhaps just make it an
   ASSERT in put_page_from_l2e?
 - With the removal of this some of the code could be made simpler:
   if (.. _PAGE_PSE  return -EINVAL;
   instead of inverse: if (! .._PAGE_PSE) ..
   I can make that an follow up patch if desired?


 docs/misc/xen-command-line.markdown |   7 --
 tools/libxc/include/xenguest.h      |   3 +-
 tools/libxc/xc_nomigrate.c          |   2 +-
 tools/libxc/xc_sr_restore.c         |   6 +-
 tools/libxl/libxl_internal.h        |   2 +-
 tools/libxl/libxl_save_callout.c    |   4 +-
 tools/libxl/libxl_save_helper.c     |   3 +-
 tools/libxl/libxl_stream_read.c     |   2 +-
 xen/arch/x86/domain.c               |   2 -
 xen/arch/x86/domain_build.c         |   2 -
 xen/arch/x86/mm.c                   | 241 ++----------------------------------
 xen/include/asm-x86/config.h        |   9 +-
 xen/include/asm-x86/guest_pt.h      |   4 +-
 xen/include/asm-x86/mm.h            |  19 ---
 xen/include/public/xen.h            |   4 +-
 15 files changed, 23 insertions(+), 287 deletions(-)

Konrad Rzeszutek Wilk (1):
      xen/libxl/libxl: RIP PV superpage.