Hi Yi,
On 9/12/2024 6:47 PM, Yi Liu wrote:
> 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, so it is reasonable to extend the IOMMU_GET_HW_INFO to
> report the PASID capability to userspace.
>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> ---
> drivers/iommu/iommufd/device.c | 27 ++++++++++++++++++++++++++-
> drivers/pci/ats.c | 32 ++++++++++++++++++++++++++++++++
> include/linux/pci-ats.h | 3 +++
> include/uapi/linux/iommufd.h | 14 +++++++++++++-
> 4 files changed, 74 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 18f94aa462ea..6b7e3e5f4598 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -4,6 +4,8 @@
> #include <linux/iommufd.h>
> #include <linux/slab.h>
> #include <linux/iommu.h>
> +#include <linux/pci.h>
> +#include <linux/pci-ats.h>
> #include <uapi/linux/iommufd.h>
> #include "../iommu-priv.h"
>
> @@ -1185,7 +1187,8 @@ 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);
> @@ -1242,6 +1245,28 @@ 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;
> +
> + if (dev_is_pci(idev->dev)) {
> + struct pci_dev *pdev = to_pci_dev(idev->dev);
> + int ctrl;
> +
> + if (pdev->is_virtfn)
> + pdev = pci_physfn(pdev);
> +
> + ctrl = pci_pasid_ctrl_status(pdev);
> + if (ctrl >= 0 && (ctrl & PCI_PASID_CTRL_ENABLE)) {
> + cmd->out_max_pasid_log2 =
> + ilog2(idev->dev->iommu->max_pasids);
> + 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 c570892b2090..886f24e3999f 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -505,4 +505,36 @@ 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_ctrl_status - Check the PASID status
> + * @pdev: PCI device structure
> + *
> + * Returns a negative value when no PASI capability is present.
s/PASI/PASID/
> + * 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_ctrl_status(struct pci_dev *pdev)
> +{
> + u16 ctrl = 0;
No need to initialize ctrl.
-Vasant
