On Fri, 18 Mar 2022 14:27:35 -0300
Jason Gunthorpe <j...@nvidia.com> wrote:
> +/**
> + * iommufd_bind_pci_device - Bind a physical device to an iommu fd
> + * @fd: iommufd file descriptor.
> + * @pdev: Pointer to a physical PCI device struct
> + * @id: Output ID number to return to userspace for this device
> + *
> + * A successful bind establishes an ownership over the device and returns
> + * struct iommufd_device pointer, otherwise returns error pointer.
> + *
> + * A driver using this API must set driver_managed_dma and must not touch
> + * the device until this routine succeeds and establishes ownership.
> + *
> + * Binding a PCI device places the entire RID under iommufd control.
> + *
> + * The caller must undo this with iommufd_unbind_device()
> + */
> +struct iommufd_device *iommufd_bind_pci_device(int fd, struct pci_dev *pdev,
> + u32 *id)
> +{
> + struct iommufd_device *idev;
> + struct iommufd_ctx *ictx;
> + struct iommu_group *group;
> + int rc;
> +
> + ictx = iommufd_fget(fd);
> + if (!ictx)
> + return ERR_PTR(-EINVAL);
> +
> + group = iommu_group_get(&pdev->dev);
> + if (!group) {
> + rc = -ENODEV;
> + goto out_file_put;
> + }
> +
> + /*
> + * FIXME: Use a device-centric iommu api and this won't work with
> + * multi-device groups
> + */
> + rc = iommu_group_claim_dma_owner(group, ictx->filp);
> + if (rc)
> + goto out_group_put;
> +
> + idev = iommufd_object_alloc(ictx, idev, IOMMUFD_OBJ_DEVICE);
> + if (IS_ERR(idev)) {
> + rc = PTR_ERR(idev);
> + goto out_release_owner;
> + }
> + idev->ictx = ictx;
> + idev->dev = &pdev->dev;
> + /* The calling driver is a user until iommufd_unbind_device() */
> + refcount_inc(&idev->obj.users);
> + /* group refcount moves into iommufd_device */
> + idev->group = group;
> +
> + /*
> + * If the caller fails after this success it must call
> + * iommufd_unbind_device() which is safe since we hold this refcount.
> + * This also means the device is a leaf in the graph and no other object
> + * can take a reference on it.
> + */
> + iommufd_object_finalize(ictx, &idev->obj);
> + *id = idev->obj.id;
> + return idev;
> +
> +out_release_owner:
> + iommu_group_release_dma_owner(group);
> +out_group_put:
> + iommu_group_put(group);
> +out_file_put:
> + fput(ictx->filp);
> + return ERR_PTR(rc);
> +}
> +EXPORT_SYMBOL_GPL(iommufd_bind_pci_device);
I'm stumped why this needs to be PCI specific. Anything beyond the RID
comment? Please enlighten. Thanks,
Alex
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