Messages in this thread | | | Date | Fri, 12 May 2023 13:38:31 +0800 | Subject | Re: [PATCH v3 3/4] iommufd: Add IOMMU_DEVICE_GET_HW_INFO | From | Baolu Lu <> |
| |
On 5/11/23 10:30 PM, Yi Liu wrote: > Under nested IOMMU translation, userspace owns the stage-1 translation > table (e.g. the stage-1 page table of Intel VT-d or the context table > of ARM SMMUv3, and etc.). Stage-1 translation tables are vendor specific, > and needs to be compatiable with the underlying IOMMU hardware. Hence, > userspace should know the IOMMU hardware capability before creating and > configuring the stage-1 translation table to kernel. > > This adds IOMMU_DEVICE_GET_HW_INFO to query the IOMMU hardware information > for a given device. The returned data is vendor specific, userspace needs > to decode it with the structure mapped by the @out_data_type field. > > As only physical devices have IOMMU hardware, so this will return error > if the given device is not a physical device. > > Co-developed-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > --- > drivers/iommu/iommufd/device.c | 72 +++++++++++++++++++++++++ > drivers/iommu/iommufd/iommufd_private.h | 1 + > drivers/iommu/iommufd/main.c | 3 ++ > include/uapi/linux/iommufd.h | 37 +++++++++++++ > 4 files changed, 113 insertions(+) > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > index 051bd8e99858..bc99d092de8f 100644 > --- a/drivers/iommu/iommufd/device.c > +++ b/drivers/iommu/iommufd/device.c > @@ -263,6 +263,78 @@ u32 iommufd_device_to_id(struct iommufd_device *idev) > } > EXPORT_SYMBOL_NS_GPL(iommufd_device_to_id, IOMMUFD); > > +static int iommufd_zero_fill_user(u64 ptr, int bytes) > +{ > + int index = 0; > + > + for (; index < bytes; index++) { > + if (put_user(0, (uint8_t __user *)u64_to_user_ptr(ptr + index))) > + return -EFAULT; > + } > + return 0; > +} > + > +int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) > +{ > + struct iommu_hw_info *cmd = ucmd->cmd; > + unsigned int length = 0, data_len; > + struct iommufd_device *idev; > + const struct iommu_ops *ops; > + void *data = NULL; > + int rc = 0; > + > + if (cmd->flags || cmd->__reserved || !cmd->data_len) > + return -EOPNOTSUPP; > + > + idev = iommufd_get_device(ucmd, cmd->dev_id); > + if (IS_ERR(idev)) > + return PTR_ERR(idev); > + > + ops = dev_iommu_ops(idev->dev); > + if (!ops->hw_info) > + goto done;
If the iommu driver doesn't provide a hw_info callback, it still returns success?
> + > + /* driver has hw_info callback should have a unique hw_info_type */ > + if (ops->hw_info_type == IOMMU_HW_INFO_TYPE_NONE) { > + pr_warn_ratelimited("iommu driver set an invalid type\n"); > + rc = -ENODEV; > + goto out_err; > + } > + > + data = ops->hw_info(idev->dev, &data_len); > + if (IS_ERR(data)) { > + rc = PTR_ERR(data); > + goto out_err; > + } > + > + length = min(cmd->data_len, data_len); > + if (copy_to_user(u64_to_user_ptr(cmd->data_ptr), data, length)) { > + rc = -EFAULT; > + goto out_err; > + } > + > + /* > + * Zero the trailing bytes if the user buffer is bigger than the > + * data size kernel actually has. > + */ > + if (length < cmd->data_len) { > + rc = iommufd_zero_fill_user(cmd->data_ptr + length, > + cmd->data_len - length); > + if (rc) > + goto out_err; > + } > + > +done: > + cmd->data_len = length; > + cmd->out_data_type = ops->hw_info_type; > + rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > + > +out_err: > + kfree(data); > + iommufd_put_object(&idev->obj); > + return rc; > +} > + > static int iommufd_group_setup_msi(struct iommufd_group *igroup, > struct iommufd_hw_pagetable *hwpt) > {
Best regards, baolu
| |