PCI: Enable PASID only if entire path supports End-End TLP prefixes
A PCIe endpoint carries the process address space identifier (PASID) in
the TLP prefix as part of the memory read/write transaction. The address
information in the TLP is relevant only for a given PASID context.
An IOMMU takes PASID value and the address information from the
TLP to look up the physical address in the system.
PASID is an End-End TLP Prefix (PCIe r4.0, sec 6.20). Sec 2.2.10.2 says
It is an error to receive a TLP with an End-End TLP Prefix by a
Receiver that does not support End-End TLP Prefixes. A TLP in
violation of this rule is handled as a Malformed TLP. This is a
reported error associated with the Receiving Port (see Section 6.2).
Prevent error condition by proactively requiring End-End TLP prefix to be
supported on the entire data path between the endpoint and the root port
before enabling PASID.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 340029b..6ba8184 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -350,6 +350,7 @@ struct pci_dev {
unsigned int ltr_path:1; /* Latency Tolerance Reporting
supported from root to here */
#endif
+ unsigned int eetlp_prefix_path:1; /* End-to-End TLP Prefix */
pci_channel_state_t error_state; /* Current connectivity state */
struct device dev; /* Generic device interface */