Re: [PATCH v7 02/28] iommufd/viommu: Explicitly define vdev->virt_id

Pranjal Shrivastava
2025-07-01T13:52:04Z

On Thu, Jun 26, 2025 at 12:34:33PM -0700, Nicolin Chen wrote:
> The "id" is too genernal to get its meaning easily. Rename it explicitly to
> "virt_id" and update the kdocs for readability. No functional changes.
>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> drivers/iommu/iommufd/iommufd_private.h | 7 ++++++-
> drivers/iommu/iommufd/driver.c | 2 +-
> drivers/iommu/iommufd/viommu.c | 4 ++--
> 3 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
> index 4f5e8cd99c96..09f895638f68 100644
> --- a/drivers/iommu/iommufd/iommufd_private.h
> +++ b/drivers/iommu/iommufd/iommufd_private.h
> @@ -634,7 +634,12 @@ struct iommufd_vdevice {
> struct iommufd_object obj;
> struct iommufd_viommu *viommu;
> struct device *dev;
> - u64 id; /* per-vIOMMU virtual ID */
> +
> + /*
> + * Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID of
> + * AMD IOMMU, and vRID of a nested Intel VT-d to a Context Table
> + */
> + u64 virt_id;
> };
>
> #ifdef CONFIG_IOMMUFD_TEST
> diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
> index 2fee399a148e..887719016804 100644
> --- a/drivers/iommu/iommufd/driver.c
> +++ b/drivers/iommu/iommufd/driver.c
> @@ -30,7 +30,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu,
> xa_lock(&viommu->vdevs);
> xa_for_each(&viommu->vdevs, index, vdev) {
> if (vdev->dev == dev) {
> - *vdev_id = vdev->id;
> + *vdev_id = vdev->virt_id;
> rc = 0;
> break;
> }
> diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
> index 25ac08fbb52a..bc8796e6684e 100644
> --- a/drivers/iommu/iommufd/viommu.c
> +++ b/drivers/iommu/iommufd/viommu.c
> @@ -111,7 +111,7 @@ void iommufd_vdevice_destroy(struct iommufd_object *obj)
> struct iommufd_viommu *viommu = vdev->viommu;
>
> /* xa_cmpxchg is okay to fail if alloc failed xa_cmpxchg previously */
> - xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
> + xa_cmpxchg(&viommu->vdevs, vdev->virt_id, vdev, NULL, GFP_KERNEL);
> refcount_dec(&viommu->obj.users);
> put_device(vdev->dev);
> }
> @@ -150,7 +150,7 @@ int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
> goto out_put_idev;
> }
>
> - vdev->id = virt_id;
> + vdev->virt_id = virt_id;
> vdev->dev = idev->dev;
> get_device(idev->dev);
> vdev->viommu = viommu;

Reviewed-by: Pranjal Shrivastava <praan@google.com>

> --
> 2.43.0
>