[PATCH v2 0/2] Add PGR response PASID requirement check in Intel IOMMU.

[sathyanarayanan . kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

Intel IOMMU responds automatically when receiving page-requests from
a PCIe endpoint and the page-request queue is full and it cannot accept
any more page-requests. When it auto-responds to page-requests with a
success to the endpoint, it automatically responds with the PASID if
the page-request had a PASID in the incoming request. IOMMU doesn't
actually have any place to check device capabilities (like whether
the device expects PASID in PGR response or not) before sending the
response message. Due to this restriction Intel IOMMU driver only
enables PASID, if the endpoint is compliant to Intel IOMMU's.

Changes since v1:
 * Changed interface name to pci_prg_resp_pasid_required().
 * Update comment header format.

Kuppuswamy Sathyanarayanan (2):
  PCI/ATS: Add pci_prg_resp_pasid_required() interface.
  iommu/vt-d: Enable PASID only if device expects PASID in PRG Response.

 drivers/iommu/intel-iommu.c   |  3 ++-
 drivers/pci/ats.c             | 31 +++++++++++++++++++++++++++++++
 include/linux/pci-ats.h       |  5 +++++
 include/uapi/linux/pci_regs.h |  1 +
 4 files changed, 39 insertions(+), 1 deletion(-)

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2.20.1