From: Yi Liu yi.l.liu@intel.com
[ Upstream commit 803f97298e7de9242eb677a1351dcafbbcc9117e ]
PASID usage requires PASID support in both device and IOMMU. Since the iommu drivers always enable the PASID capability for the device if it is supported, this extends the IOMMU_GET_HW_INFO to report the PASID capability to userspace. Also, enhances the selftest accordingly.
Link: https://patch.msgid.link/r/20250321180143.8468-5-yi.l.liu@intel.com Cc: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Kevin Tian kevin.tian@intel.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Tested-by: Zhangfei Gao zhangfei.gao@linaro.org #aarch64 platform Tested-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommufd/device.c | 34 +++++++++++++++++++++++++++++++++- drivers/pci/ats.c | 33 +++++++++++++++++++++++++++++++++ include/linux/pci-ats.h | 3 +++ include/uapi/linux/iommufd.h | 14 +++++++++++++- 4 files changed, 82 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index 3c7800d4ab622..66a6b7466820d 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -3,6 +3,7 @@ */ #include <linux/iommu.h> #include <linux/iommufd.h> +#include <linux/pci-ats.h> #include <linux/slab.h> #include <uapi/linux/iommufd.h>
@@ -1304,7 +1305,8 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) void *data; int rc;
- if (cmd->flags || cmd->__reserved) + if (cmd->flags || cmd->__reserved[0] || cmd->__reserved[1] || + cmd->__reserved[2]) return -EOPNOTSUPP;
idev = iommufd_get_device(ucmd, cmd->dev_id); @@ -1361,6 +1363,36 @@ int iommufd_get_hw_info(struct iommufd_ucmd *ucmd) if (device_iommu_capable(idev->dev, IOMMU_CAP_DIRTY_TRACKING)) cmd->out_capabilities |= IOMMU_HW_CAP_DIRTY_TRACKING;
+ cmd->out_max_pasid_log2 = 0; + /* + * Currently, all iommu drivers enable PASID in the probe_device() + * op if iommu and device supports it. So the max_pasids stored in + * dev->iommu indicates both PASID support and enable status. A + * non-zero dev->iommu->max_pasids means PASID is supported and + * enabled. The iommufd only reports PASID capability to userspace + * if it's enabled. + */ + if (idev->dev->iommu->max_pasids) { + cmd->out_max_pasid_log2 = ilog2(idev->dev->iommu->max_pasids); + + if (dev_is_pci(idev->dev)) { + struct pci_dev *pdev = to_pci_dev(idev->dev); + int ctrl; + + ctrl = pci_pasid_status(pdev); + + WARN_ON_ONCE(ctrl < 0 || + !(ctrl & PCI_PASID_CTRL_ENABLE)); + + if (ctrl & PCI_PASID_CTRL_EXEC) + cmd->out_capabilities |= + IOMMU_HW_CAP_PCI_PASID_EXEC; + if (ctrl & PCI_PASID_CTRL_PRIV) + cmd->out_capabilities |= + IOMMU_HW_CAP_PCI_PASID_PRIV; + } + } + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); out_free: kfree(data); diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index c6b266c772c81..ec6c8dbdc5e9c 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -538,4 +538,37 @@ int pci_max_pasids(struct pci_dev *pdev) return (1 << FIELD_GET(PCI_PASID_CAP_WIDTH, supported)); } EXPORT_SYMBOL_GPL(pci_max_pasids); + +/** + * pci_pasid_status - Check the PASID status + * @pdev: PCI device structure + * + * Returns a negative value when no PASID capability is present. + * Otherwise the value of the control register is returned. + * Status reported are: + * + * PCI_PASID_CTRL_ENABLE - PASID enabled + * PCI_PASID_CTRL_EXEC - Execute permission enabled + * PCI_PASID_CTRL_PRIV - Privileged mode enabled + */ +int pci_pasid_status(struct pci_dev *pdev) +{ + int pasid; + u16 ctrl; + + if (pdev->is_virtfn) + pdev = pci_physfn(pdev); + + pasid = pdev->pasid_cap; + if (!pasid) + return -EINVAL; + + pci_read_config_word(pdev, pasid + PCI_PASID_CTRL, &ctrl); + + ctrl &= PCI_PASID_CTRL_ENABLE | PCI_PASID_CTRL_EXEC | + PCI_PASID_CTRL_PRIV; + + return ctrl; +} +EXPORT_SYMBOL_GPL(pci_pasid_status); #endif /* CONFIG_PCI_PASID */ diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h index 0e8b74e63767a..75c6c86cf09dc 100644 --- a/include/linux/pci-ats.h +++ b/include/linux/pci-ats.h @@ -42,6 +42,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features); void pci_disable_pasid(struct pci_dev *pdev); int pci_pasid_features(struct pci_dev *pdev); int pci_max_pasids(struct pci_dev *pdev); +int pci_pasid_status(struct pci_dev *pdev); #else /* CONFIG_PCI_PASID */ static inline int pci_enable_pasid(struct pci_dev *pdev, int features) { return -EINVAL; } @@ -50,6 +51,8 @@ static inline int pci_pasid_features(struct pci_dev *pdev) { return -EINVAL; } static inline int pci_max_pasids(struct pci_dev *pdev) { return -EINVAL; } +static inline int pci_pasid_status(struct pci_dev *pdev) +{ return -EINVAL; } #endif /* CONFIG_PCI_PASID */
#endif /* LINUX_PCI_ATS_H */ diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index 78747b24bd0fb..9495604e40b06 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -608,9 +608,17 @@ enum iommu_hw_info_type { * IOMMU_HWPT_GET_DIRTY_BITMAP * IOMMU_HWPT_SET_DIRTY_TRACKING * + * @IOMMU_HW_CAP_PCI_PASID_EXEC: Execute Permission Supported, user ignores it + * when the struct + * iommu_hw_info::out_max_pasid_log2 is zero. + * @IOMMU_HW_CAP_PCI_PASID_PRIV: Privileged Mode Supported, user ignores it + * when the struct + * iommu_hw_info::out_max_pasid_log2 is zero. */ enum iommufd_hw_capabilities { IOMMU_HW_CAP_DIRTY_TRACKING = 1 << 0, + IOMMU_HW_CAP_PCI_PASID_EXEC = 1 << 1, + IOMMU_HW_CAP_PCI_PASID_PRIV = 1 << 2, };
/** @@ -626,6 +634,9 @@ enum iommufd_hw_capabilities { * iommu_hw_info_type. * @out_capabilities: Output the generic iommu capability info type as defined * in the enum iommu_hw_capabilities. + * @out_max_pasid_log2: Output the width of PASIDs. 0 means no PASID support. + * PCI devices turn to out_capabilities to check if the + * specific capabilities is supported or not. * @__reserved: Must be 0 * * Query an iommu type specific hardware information data from an iommu behind @@ -649,7 +660,8 @@ struct iommu_hw_info { __u32 data_len; __aligned_u64 data_uptr; __u32 out_data_type; - __u32 __reserved; + __u8 out_max_pasid_log2; + __u8 __reserved[3]; __aligned_u64 out_capabilities; }; #define IOMMU_GET_HW_INFO _IO(IOMMUFD_TYPE, IOMMUFD_CMD_GET_HW_INFO)