[PATCH v8 00/14] Implement the XEN_DOMCTL_memory_mapping hypercall for ARM

[Arianna Avanzini <avanzini.arianna@gmail.com>]

Hello,

this is a new version - the eighth - of my implementation proposal for the
memory_mapping DOMCTL for the ARM architecture. As usual, this cover letter just
lists the most relevant changes performed on the patchset, while a more detailed
description can be found in the description and changelog of each patch; also,
some more information about the patch series' origin can be found in the last
full cover letter ([1]).

First of all, the commit descriptions have been reworded to get rid of tentative
phrases that were pointless in that context, as suggested by Dario Faggioli.

Patch 0002 has been modified to revert some uncorrect changes due to my
misunderstanding of previous comments, as pointed out by Julien Grall. Also,
according to his suggestions, an error message has been added to let a failure
encountered during an unmap be less obscure. The error path has been improved
to include unmapping previously-created page-table mappings, unlocking the
p2m_lock and flushing the TLBs in case some mappings have been successfully
removed.

Patch 0004 has been changed to address issues pointed out by Julien Grall and
Ian Campbell. Now the correct DIV_ROUND_UP() macro is used instead of the
ternary operator, and the map_one_mmio() function, defined for the xgene-storm
platform, accepts pfns as arguments instead of paddr_t. Also, the function
apply_p2m_changes() is now called from map_mmio_regions() with the correct
count.

A new patch 0005 has been added to let the map_mmio_regions() function for ARM
unmap partially-mapped I/O-memory regions if mapping a page fails, as suggested
by Julien Grall. The approach which has been used includes having the function
apply_p2m_changes() return, in the case of an error, the number of pages that
have been successfully mapped, therefore allowing the caller to undo what has
been done, if necessary. The definition of unmap_mmio_regions() for ARM has been
moved to this patch and now uses the correct count as indicated by Julien Grall.

The title and description of patch 0006 have been changed to (hopefully) better
fit the patch content, as requested by Jan Beulich.

The patch factoring out map and unmap operations from the x86 version of the
memory_mapping DOMCTL has been split into two, as suggested by Jan Beulich, to
make the review easier: patch 0007 now just cleans up existing code, by letting
mfn + nr_mfns be computed only once and by changing the name of the tmp_rc local
variable to rc; patch 0009 instead actually factors out the operations.

A new patch 0008 now adds an empty stub for the ARM architecture of the MTRR-
related function memory_type_changed(), currently available only for x86, and
makes its definition common to both x86 and ARM. This was requested by Jan
Beulich and Ian Campbell.

The call to PERROR() in patch 0012 has been fixed, as it showed an error message
whose meaning was the opposite of the correct one, as pointed out by Jan
Beulich.

The patch which implemented a separation of the functions of the memory_mapping
and iomem_permission DOMCTLs has now been split into two, as suggested by Jan
Beulich: patch 0013 now contains only libxl-related preparatory changes, while
patch 0014 actually implements the separation. As for patch 0014, changes
performed on the iomem_permission DOMCTL handling code have been dropped, while
the permission checks performed by memory_mapping have been changed to be more
conservative and check both the calling domain and the grantee domain's
permissions.
As of now, patch 0014 performs the separation only for I/O memory and not for
I/O ports (as was instead suggested by Jan Beulich) because, as far as I know,
Julien Grall is working on the I/O ports patch series, and I'm afraid I might be
conflicting with his work. I am however surely willing to add a patch for that
if he is OK with it.

The code has again been tested on a cubieboard2, with Linux v3.15-rc3 as a dom0
and ERIKA Enterprise ([2]) as a domU. The x86 bits have been tested on an x86_64
machine, as I forgot to say in the last versions of the patchset and Jan Beulich
pointed out; in particular, this last version, has been tested with Linux 
3.15.0-rc5 as both dom0 and domU.
Any feedback about this new version of the patchset is more than welcome,
Arianna

[1] http://lists.xen.org/archives/html/xen-devel/2014-03/msg01724.html
[2] http://erika.tuxfamily.org/drupal/

Arianna Avanzini (14):
  arch/arm: domain build: let dom0 access I/O memory of mapped devices
  arch/arm: add consistency check to REMOVE p2m changes
  arch/arm: let map_mmio_regions() take pfn as parameters
  arch/arm: let map_mmio_regions() use start and count
  arch/arm: unmap partially-mapped I/O-memory regions
  arch/x86: warn if to-be-removed mapping does not exist
  arch/x86: cleanup memory_mapping DOMCTL
  xen/common: move memory_type_changed() function to common code
  xen/x86: factor out map and unmap from the memory_mapping DOMCTL
  xen/common: move the memory_mapping DOMCTL hypercall to common code
  tools/libxl: parse optional start gfn from the iomem config option
  tools/libxl: handle the iomem parameter with the memory_mapping hcall
  tools/libxl: explicitly grant access to needed I/O-memory ranges
  xen/common: do not implicitly permit access to mapped I/O memory

 docs/man/xl.cfg.pod.5                | 18 +++++--
 tools/libxc/xc_domain.c              | 12 +++++
 tools/libxl/libxl.h                  | 10 ++++
 tools/libxl/libxl_create.c           | 34 +++++++++++++
 tools/libxl/libxl_internal.h         |  1 +
 tools/libxl/libxl_pci.c              | 26 ++++------
 tools/libxl/libxl_types.idl          |  4 ++
 tools/libxl/xl_cmdimpl.c             | 17 ++++---
 xen/arch/arm/Makefile                |  1 +
 xen/arch/arm/domain_build.c          | 18 +++++--
 xen/arch/arm/gic.c                   | 15 +++---
 xen/arch/arm/mtrr.c                  |  6 +++
 xen/arch/arm/p2m.c                   | 99 ++++++++++++++++++++++++++++--------
 xen/arch/arm/platforms/exynos5.c     |  9 ++--
 xen/arch/arm/platforms/omap5.c       | 17 +++----
 xen/arch/arm/platforms/xgene-storm.c | 16 +++---
 xen/arch/x86/domctl.c                | 76 ---------------------------
 xen/arch/x86/mm/p2m.c                | 53 +++++++++++++++++--
 xen/common/domctl.c                  | 55 +++++++++++++++++++-
 xen/include/asm-arm/mm.h             |  2 +
 xen/include/asm-arm/mtrr.h           |  6 +++
 xen/include/asm-arm/p2m.h            | 11 ++--
 xen/include/asm-x86/mtrr.h           |  2 +-
 xen/include/asm-x86/p2m.h            |  3 +-
 xen/include/xen/mtrr.h               |  8 +++
 xen/include/xen/p2m-common.h         | 16 ++++++
 26 files changed, 365 insertions(+), 170 deletions(-)
 create mode 100644 xen/arch/arm/mtrr.c
 create mode 100644 xen/include/asm-arm/mtrr.h
 create mode 100644 xen/include/xen/mtrr.h
 create mode 100644 xen/include/xen/p2m-common.h

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1.9.2