Commit db8a6a29 authored by Lu Baolu's avatar Lu Baolu Committed by Carlos Llamas
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UPSTREAM: PCI: Enable PASID only when ACS RR & UF enabled on upstream path



The Requester ID/Process Address Space ID (PASID) combination
identifies an address space distinct from the PCI bus address space,
e.g., an address space defined by an IOMMU.

But the PCIe fabric routes Memory Requests based on the TLP address,
ignoring any PASID (PCIe r6.0, sec 2.2.10.4), so a TLP with PASID that
SHOULD go upstream to the IOMMU may instead be routed as a P2P
Request if its address falls in a bridge window.

To ensure that all Memory Requests with PASID are routed upstream,
only enable PASID if ACS P2P Request Redirect and Upstream Forwarding
are enabled for the path leading to the device.

Suggested-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Suggested-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Tested-by: default avatarTony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-5-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>

(cherry picked from commit 201007ef)
Bug: 271394577
Change-Id: I302e3c26cd5d3a0122f4ef52a0191959aef574c0
Signed-off-by: default avatarMichael Shavit <mshavit@google.com>
parent 36db10b1
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