[PATCH v8 0/5] Fix PF/VF dependency issue

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

The current implementation of ATS, PASID, and PRI does not handle VF
dependencies correctly.  These are essentially Kuppuswamy's patches; I
reordered and tweaked them slightly.

Please treat this as a proposal, not a done deal, and post a v9 with any
changes needed.

Changes since v7:
 * Moved PRI & PASID capability offset caching to last since they're just
   optimizations
 * Cached offsets at first use instead of adding _init() functions
 * Dropped complicated pci_prg_resp_pasid_required() #ifdefs by just
   searching for the capability again
 * Dropped EA/VF validation since it only enforces spec language without
   fixing any known issues

Changes since v6:
 * Removed locking interfaces used in v6.
 * Made necessary changes to PRI/PASID enable/disable calls to allow
   register changes only for PF.

Changes since v5:
 * Created new patches for PRI/PASID capability caching.
 * Removed individual locks (pri_lock, pasid_lock) and added common
   resource lock to synchronize PRI/PASID updates between PF/VF.
 * Addressed comments from Bjorn Helgaas.

Changes since v4:
 * Defined empty functions for pci_pri_init() and pci_pasid_init() for cases
   where CONFIG_PCI_PRI and CONFIG_PCI_PASID are not enabled.

Changes since v3:
 * Fixed critical path (lock context) in pci_restore_*_state functions.

Changes since v2:
 * Added locking mechanism to synchronize accessing PF registers in VF.
 * Removed spec compliance checks in patches.
 * Addressed comments from Bjorn Helgaas.

Changes since v1:
 * Added more details about the patches in commit log.
 * Removed bulk spec check patch.
 * Addressed comments from Bjorn Helgaas.


Link: https://lore.kernel.org/r/cover.1567029860.git.sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx v7

Kuppuswamy Sathyanarayanan (5):
  PCI/ATS: Handle sharing of PF PRI Capability with all VFs
  PCI/ATS: Handle sharing of PF PASID Capability with all VFs
  PCI/ATS: Disable PF/VF ATS service independently
  PCI/ATS: Cache PRI Capability offset
  PCI/ATS: Cache PASID Capability offset

 drivers/pci/ats.c   | 153 +++++++++++++++++++++++++++-----------------
 include/linux/pci.h |   3 +-
 2 files changed, 96 insertions(+), 60 deletions(-)

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2.23.0.187.g17f5b7556c-goog