From 7ce3f912ae0a79e5d738a3ae1f158b281973e849 Mon Sep 17 00:00:00 2001 From: Sinan Kaya Date: Sat, 30 Jun 2018 11:24:24 -0400 Subject: 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 Signed-off-by: Bjorn Helgaas --- drivers/pci/ats.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/pci/ats.c') 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; -- cgit v1.2.3