Re: [Intel-gfx] [PATCH v7 4/9] iommufd: Add iommufd_ctx_has_group()

Alex Williamson
2023-06-08T21:40:59Z

On Fri, 2 Jun 2023 05:15:10 -0700
Yi Liu <yi.l.liu@intel.com> wrote:

> This adds the helper to check if any device within the given iommu_group
> has been bound with the iommufd_ctx. This is helpful for the checking on
> device ownership for the devices which have not been bound but cannot be
> bound to any other iommufd_ctx as the iommu_group has been bound.
>
> Tested-by: Terrence Xu <terrence.xu@intel.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
> drivers/iommu/iommufd/device.c | 30 ++++++++++++++++++++++++++++++
> include/linux/iommufd.h | 8 ++++++++
> 2 files changed, 38 insertions(+)
>
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 4f9b2142274c..4571344c8508 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -98,6 +98,36 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
> }
> EXPORT_SYMBOL_NS_GPL(iommufd_device_bind, IOMMUFD);
>
> +/**
> + * iommufd_ctx_has_group - True if any device within the group is bound
> + * to the ictx
> + * @ictx: iommufd file descriptor
> + * @group: Pointer to a physical iommu_group struct
> + *
> + * True if any device within the group has been bound to this ictx, ex. via
> + * iommufd_device_bind(), therefore implying ictx ownership of the group.
> + */
> +bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group)
> +{
> + struct iommufd_object *obj;
> + unsigned long index;
> +
> + if (!ictx || !group)
> + return false;
> +
> + xa_lock(&ictx->objects);
> + xa_for_each(&ictx->objects, index, obj) {
> + if (obj->type == IOMMUFD_OBJ_DEVICE &&
> + container_of(obj, struct iommufd_device, obj)->group == group) {
> + xa_unlock(&ictx->objects);
> + return true;
> + }
> + }
> + xa_unlock(&ictx->objects);
> + return false;
> +}
> +EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, IOMMUFD);
> +
> /**
> * iommufd_device_unbind - Undo iommufd_device_bind()
> * @idev: Device returned by iommufd_device_bind()
> diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
> index 1129a36a74c4..33fe57e95e42 100644
> --- a/include/linux/iommufd.h
> +++ b/include/linux/iommufd.h
> @@ -16,6 +16,7 @@ struct page;
> struct iommufd_ctx;
> struct iommufd_access;
> struct file;
> +struct iommu_group;
>
> struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
> struct device *dev, u32 *id);
> @@ -50,6 +51,7 @@ void iommufd_ctx_get(struct iommufd_ctx *ictx);
> #if IS_ENABLED(CONFIG_IOMMUFD)
> struct iommufd_ctx *iommufd_ctx_from_file(struct file *file);
> void iommufd_ctx_put(struct iommufd_ctx *ictx);
> +bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group);
>
> int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova,
> unsigned long length, struct page **out_pages,
> @@ -71,6 +73,12 @@ static inline void iommufd_ctx_put(struct iommufd_ctx *ictx)
> {
> }
>
> +static inline bool iommufd_ctx_has_group(struct iommufd_ctx *ictx,
> + struct iommu_group *group)
> +{
> + return false;
> +}
> +
> static inline int iommufd_access_pin_pages(struct iommufd_access *access,
> unsigned long iova,
> unsigned long length,

It looks like the v12 cdev series no longer requires this stub? We
haven't used this function except from iommufd specific code since v5.
Thanks,

Alex