IOMMU, vtd and iotlb flush rework (v3)

[Jean Guyader <jean.guyader@eu.citrix.com>]

In one of my previous email I detailed a bug I was seeing when passing
through a Intel GPU on a guest that has more that 4G or RAM.

Allen suggested that I go for the Plan B but after a discussion with Tim
we agreed that Plan B was way to disruptive in term of code change.

This patch series implements Plan A.

http://xen.1045712.n5.nabble.com/VTD-Intel-iommu-IOTLB-flush-really-slow-td4952866.html

Changes between v2 and v3:
        - Check for the presence iotlb_flush_all callback before calling it.

Changes between v1 and v2:
       - Move size in struct xen_add_to_physmap in padding between .domid and .space.
       - Store iommu_dont_flush per cpu
       - Change the code in hvmloader to relocate by batch of 64K, .size is now 16 bits.

Jean Guyader (6):
      vtd: Refactor iotlb flush code
      iommu: Introduce iommu_flush and iommu_flush_all.
      add_to_physmap: Move the code for XENMEM_add_to_physmap.
      mm: New XENMEM, XENMEM_add_to_physmap_gmfn_range
      hvmloader: Change memory relocation loop when overlap with PCI hole.
      Introduce per cpu flag (iommu_dont_flush_iotlb) to avoid unnecessary iotlb flush

 tools/firmware/hvmloader/pci.c      |   20 +++-
 xen/arch/x86/mm.c                   |  203 +++++++++++++++++++++--------------
 xen/drivers/passthrough/iommu.c     |   25 +++++
 xen/drivers/passthrough/vtd/iommu.c |  100 ++++++++++--------
 xen/include/public/memory.h         |    4 +
 xen/include/xen/iommu.h             |    7 ++
 6 files changed, 230 insertions(+), 129 deletions(-)