Enhance DMAR drivers to handle PCI/memory hotplug events

Intel DMA/interrupt remapping drivers scan available PCI/memory devices at startup and cache discovered hardware topologies. They don't update cached information if PCI/memory hotplug event happens at runtime, then the stale information may break DMA/interrupt remapping logic.

This patchset first (Patch 1-12) tries to introduces some helper functions and fixes several bugs, then (Patch 13,14) uses a global rwsem and RCU to protect global DMA/interrupt remapping data structures, and finally (Patch 15-17) hook PCI/memory hotplug events to update cached information.

It's also a preparation for supporting of DMA/interrupt remapping hotplug.

V1->V2:
1) fix more bugs in dealing with identify mapping domain
2) address round 1 review comments

Jiang Liu (17):
iommu/vt-d: avoid double free of g_iommus on error recovery path iommu/vt-d: avoid caching stale domain_device_info and fix memory
leak
iommu/vt-d: avoid caching stale domain_device_info when hot-removing
PCI device
iommu/vt-d: factor out dmar_alloc_dev_scope() for later reuse iommu/vt-d: move private structures and variables into intel-iommu.c iommu/vt-d: simplify function get_domain_for_dev() iommu/vt-d: free resources if failed to create domain for PCIe
endpoint
iommu/vt-d: reduce duplicated code to handle virtual machine domains iommu/vt-d: fix incorrect iommu_count for si_domain iommu/vt-d: check for NULL pointer when freeing IOMMU data structure iommu/vt-d: fix error in detect ATS capability
iommu/vt-d: introduce macro for_each_dev_scope() to walk device scope
entries
iommu/vt-d: introduce a rwsem to protect global data structures iommu/vt-d: use RCU to protect global resources in interrupt context iommu/vt-d, PCI: update DRHD/RMRR/ATSR device scope caches when PCI
hotplug happens
iommu/vt-d, PCI: unify the way to process DMAR device scope array iommu/vt-d: update IOMMU state when memory hotplug happens

 drivers/iommu/dmar.c                |  412 +++++++++++++------
 drivers/iommu/intel-iommu.c         |  750 ++++++++++++++++++-----------------
 drivers/iommu/intel_irq_remapping.c |  108 +++--
 drivers/iommu/iova.c                |   64 ++-
 include/linux/dmar.h                |   74 ++--
 include/linux/iova.h                |    2 +
 6 files changed, 848 insertions(+), 562 deletions(-)

1.7.10.4