Re: [PATCH v6 30/33] backends/iommufd: Retrieve PASID width from iommufd_backend_get_device_info()

["Cédric Le Goater" <clg@redhat.com>]

On 11/20/25 14:22, Shameer Kolothum wrote:
> Retrieve PASID width from iommufd_backend_get_device_info() and store it
> in HostIOMMUDeviceCaps for later use.
> 
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.

> ---
>   backends/iommufd.c                 | 6 +++++-
>   hw/arm/smmuv3-accel.c              | 3 ++-
>   hw/vfio/iommufd.c                  | 7 +++++--
>   include/system/host_iommu_device.h | 3 +++
>   include/system/iommufd.h           | 3 ++-
>   5 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/backends/iommufd.c b/backends/iommufd.c
> index e68a2c934f..6381f9664b 100644
> --- a/backends/iommufd.c
> +++ b/backends/iommufd.c
> @@ -388,7 +388,8 @@ bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be,
>   
>   bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>                                        uint32_t *type, void *data, uint32_t len,
> -                                     uint64_t *caps, Error **errp)
> +                                     uint64_t *caps, uint8_t *max_pasid_log2,
> +                                     Error **errp)
>   {
>       struct iommu_hw_info info = {
>           .size = sizeof(info),
> @@ -407,6 +408,9 @@ bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>       g_assert(caps);
>       *caps = info.out_capabilities;
>   
> +    if (max_pasid_log2) {
> +        *max_pasid_log2 = info.out_max_pasid_log2;
> +    }
>       return true;
>   }
>   
> diff --git a/hw/arm/smmuv3-accel.c b/hw/arm/smmuv3-accel.c
> index 35a94c720a..254d29ee2d 100644
> --- a/hw/arm/smmuv3-accel.c
> +++ b/hw/arm/smmuv3-accel.c
> @@ -113,7 +113,8 @@ smmuv3_accel_hw_compatible(SMMUv3State *s, HostIOMMUDeviceIOMMUFD *idev,
>       uint64_t caps;
>   
>       if (!iommufd_backend_get_device_info(idev->iommufd, idev->devid, &data_type,
> -                                         &info, sizeof(info), &caps, errp)) {
> +                                         &info, sizeof(info), &caps, NULL,
> +                                         errp)) {
>           return false;
>       }
>   
> diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
> index ca8a6b7029..bbe944d7cc 100644
> --- a/hw/vfio/iommufd.c
> +++ b/hw/vfio/iommufd.c
> @@ -353,7 +353,8 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev,
>        * instead.
>        */
>       if (!iommufd_backend_get_device_info(vbasedev->iommufd, vbasedev->devid,
> -                                         &type, NULL, 0, &hw_caps, errp)) {
> +                                         &type, NULL, 0, &hw_caps, NULL,
> +                                         errp)) {
>           return false;
>       }
>   
> @@ -889,19 +890,21 @@ static bool hiod_iommufd_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
>       HostIOMMUDeviceCaps *caps = &hiod->caps;
>       VendorCaps *vendor_caps = &caps->vendor_caps;
>       enum iommu_hw_info_type type;
> +    uint8_t max_pasid_log2;
>       uint64_t hw_caps;
>   
>       hiod->agent = opaque;
>   
>       if (!iommufd_backend_get_device_info(vdev->iommufd, vdev->devid, &type,
>                                            vendor_caps, sizeof(*vendor_caps),
> -                                         &hw_caps, errp)) {
> +                                         &hw_caps, &max_pasid_log2, errp)) {
>           return false;
>       }
>   
>       hiod->name = g_strdup(vdev->name);
>       caps->type = type;
>       caps->hw_caps = hw_caps;
> +    caps->max_pasid_log2 = max_pasid_log2;
>   
>       idev = HOST_IOMMU_DEVICE_IOMMUFD(hiod);
>       idev->iommufd = vdev->iommufd;
> diff --git a/include/system/host_iommu_device.h b/include/system/host_iommu_device.h
> index ab849a4a82..bfb2b60478 100644
> --- a/include/system/host_iommu_device.h
> +++ b/include/system/host_iommu_device.h
> @@ -30,6 +30,8 @@ typedef union VendorCaps {
>    * @hw_caps: host platform IOMMU capabilities (e.g. on IOMMUFD this represents
>    *           the @out_capabilities value returned from IOMMU_GET_HW_INFO ioctl)
>    *
> + * @max_pasid_log2: width of PASIDs supported by host IOMMU device
> + *
>    * @vendor_caps: host platform IOMMU vendor specific capabilities (e.g. on
>    *               IOMMUFD this represents a user-space buffer filled by kernel
>    *               with host IOMMU @type specific hardware information data)
> @@ -37,6 +39,7 @@ typedef union VendorCaps {
>   typedef struct HostIOMMUDeviceCaps {
>       uint32_t type;
>       uint64_t hw_caps;
> +    uint8_t max_pasid_log2;
>       VendorCaps vendor_caps;
>   } HostIOMMUDeviceCaps;
>   #endif
> diff --git a/include/system/iommufd.h b/include/system/iommufd.h
> index 41e216c677..aa78bf1e1d 100644
> --- a/include/system/iommufd.h
> +++ b/include/system/iommufd.h
> @@ -71,7 +71,8 @@ int iommufd_backend_unmap_dma(IOMMUFDBackend *be, uint32_t ioas_id,
>                                 hwaddr iova, uint64_t size);
>   bool iommufd_backend_get_device_info(IOMMUFDBackend *be, uint32_t devid,
>                                        uint32_t *type, void *data, uint32_t len,
> -                                     uint64_t *caps, Error **errp);
> +                                     uint64_t *caps, uint8_t *max_pasid_log2,
> +                                     Error **errp);
>   bool iommufd_backend_alloc_hwpt(IOMMUFDBackend *be, uint32_t dev_id,
>                                   uint32_t pt_id, uint32_t flags,
>                                   uint32_t data_type, uint32_t data_len,