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iommufd: Extend IOMMU_GET_HW_INFO to report PASID capability

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[ 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>
This commit is contained in:
Yi Liu
2025-03-21 11:01:42 -07:00
committed by Greg Kroah-Hartman
parent e506751b7d
commit b4c11dd41c
4 changed files with 82 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/iommu/iommufd/device.c
View File

@@ -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);

33
drivers/pci/ats.c
View File

@@ -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 */

3
include/linux/pci-ats.h
View File

@@ -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 */

14
include/uapi/linux/iommufd.h
View File

@@ -504,9 +504,17 @@ 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,
};
/**
@@ -522,6 +530,9 @@ 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
@@ -545,7 +556,8 @@ 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)