[PATCH V3] PCI: Enable PASID when End-to-End TLP is supported by all bridges
From: Sinan Kaya <hidden>
Date: 2018-06-30 15:24:34
Also in:
linux-arm-msm, linux-pci, lkml
Subsystem:
pci subsystem, the rest · Maintainers:
Bjorn Helgaas, Linus Torvalds
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-to-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 <redacted> --- drivers/pci/ats.c | 3 +++ drivers/pci/probe.c | 24 ++++++++++++++++++++++++ include/linux/pci.h | 1 + include/uapi/linux/pci_regs.h | 1 + 4 files changed, 29 insertions(+)
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 4923a2a..5b78f3b 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;
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ac876e3..39fd3ac 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c@@ -2042,6 +2042,29 @@ static void pci_configure_ltr(struct pci_dev *dev) #endif } +static void pci_configure_eetlp_prefix(struct pci_dev *dev) +{ +#ifdef CONFIG_PCI_PASID + struct pci_dev *bridge; + u32 cap; + + if (!pci_is_pcie(dev)) + return; + + pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap); + if (!(cap & PCI_EXP_DEVCAP2_E2ETLP)) + return; + + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) + dev->eetlp_prefix_path = 1; + else { + bridge = pci_upstream_bridge(dev); + if (bridge && bridge->eetlp_prefix_path) + dev->eetlp_prefix_path = 1; + } +#endif +} + static void pci_configure_device(struct pci_dev *dev) { struct hotplug_params hpp;
@@ -2051,6 +2074,7 @@ static void pci_configure_device(struct pci_dev *dev) pci_configure_extended_tags(dev, NULL); pci_configure_relaxed_ordering(dev); pci_configure_ltr(dev); + pci_configure_eetlp_prefix(dev); memset(&hpp, 0, sizeof(hpp)); ret = pci_get_hp_params(dev, &hpp);
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 */
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 4da87e2..a617ab2 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h@@ -636,6 +636,7 @@ #define PCI_EXP_DEVCAP2_OBFF_MASK 0x000c0000 /* OBFF support mechanism */ #define PCI_EXP_DEVCAP2_OBFF_MSG 0x00040000 /* New message signaling */ #define PCI_EXP_DEVCAP2_OBFF_WAKE 0x00080000 /* Re-use WAKE# for OBFF */ +#define PCI_EXP_DEVCAP2_E2ETLP 0x00200000 /* End-to-End TLP Prefix */ #define PCI_EXP_DEVCTL2 40 /* Device Control 2 */ #define PCI_EXP_DEVCTL2_COMP_TIMEOUT 0x000f /* Completion Timeout Value */ #define PCI_EXP_DEVCTL2_COMP_TMOUT_DIS 0x0010 /* Completion Timeout Disable */
--
2.7.4