+iommu folks. On 5/19/2018 12:52 PM, Sinan Kaya wrote: > 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. > > A translation agent takes PASID value and the address information from the > TLP to look up the physical address in the system. > > If a bridge drops the TLP prefix, the translation agent can resolve the > address to an incorrect location and cause data corruption. Prevent > this condition by requiring End-to-End TLP prefix to be supported on the > entire data path between the endpoint and the root port. > > Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx> > --- > drivers/pci/ats.c | 16 ++++++++++++++++ > include/uapi/linux/pci_regs.h | 1 + > 2 files changed, 17 insertions(+) > > diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c > index 89305b5..0bcded5 100644 > --- a/drivers/pci/ats.c > +++ b/drivers/pci/ats.c > @@ -265,7 +265,9 @@ EXPORT_SYMBOL_GPL(pci_reset_pri); > int pci_enable_pasid(struct pci_dev *pdev, int features) > { > u16 control, supported; > + struct pci_dev *bridge; > int pos; > + u32 cap; > > if (WARN_ON(pdev->pasid_enabled)) > return -EBUSY; > @@ -274,6 +276,20 @@ int pci_enable_pasid(struct pci_dev *pdev, int features) > if (!pos) > return -EINVAL; > > + bridge = pci_upstream_bridge(pdev); > + while (bridge) { > + if (!pci_find_capability(bridge, PCI_CAP_ID_EXP)) > + return -EINVAL; > + > + if (pcie_capability_read_dword(bridge, PCI_EXP_DEVCAP2, &cap)) > + return -EINVAL; > + > + if (!(cap & PCI_EXP_DEVCAP2_E2ETLP)) > + return -EINVAL; > + > + bridge = pci_upstream_bridge(bridge); > + } > + > pci_read_config_word(pdev, pos + PCI_PASID_CAP, &supported); > supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV; > > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h > index 103ba79..d91dea5 100644 > --- a/include/uapi/linux/pci_regs.h > +++ b/include/uapi/linux/pci_regs.h > @@ -634,6 +634,7 @@ > #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 */ > -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html