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

From: Bjorn Helgaas
Date: Thu Sep 05 2019 - 15:31:55 EST


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