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| author |   Sinan Kaya <okaya@codeaurora.org> | 2018-06-30 11:24:24 -0400 |
|---|---|---|
| committer |   Bjorn Helgaas <bhelgaas@google.com> | 2018-06-30 14:10:03 -0500 |
| commit | 7ce3f912ae0a79e5d738a3ae1f158b281973e849 (patch) | |
| tree | 69c2b3d22573fa0a3567e4c3e093fc1fb70d7965 /drivers/pci/ats.c | |
| parent | Linux 4.18-rc1 (diff) | |
| download | linux-dev-7ce3f912ae0a79e5d738a3ae1f158b281973e849.tar.xz linux-dev-7ce3f912ae0a79e5d738a3ae1f158b281973e849.zip | |
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>
Diffstat (limited to 'drivers/pci/ats.c')
| -rw-r--r-- | drivers/pci/ats.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index 4923a2a8e14b..5b78f3b1b918 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -273,6 +273,9 @@ int pci_enable_pasid(struct pci_dev *pdev, int features) if (WARN_ON(pdev->pasid_enabled)) return -EBUSY; + if (!pdev->eetlp_prefix_path) + return -EINVAL; + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PASID); if (!pos) return -EINVAL; |