Re: [PATCH v4 24/27] backends/iommufd: Retrieve PASID width from iommufd_backend_get_device_info()

[Eric Auger <eric.auger@redhat.com>]

On 10/1/25 3:50 PM, Jonathan Cameron wrote:
> On Mon, 29 Sep 2025 14:36:40 +0100
> Shameer Kolothum <skolothumtho@nvidia.com> wrote:
>
> Bring the bit of the description in the title down here as well.
> Depending on what tools people use for browsing git it might
> end up in very different places on their screen.
+1

Eric
>
>> And store it in HostIOMMUDeviceCaps for later use.
>>
>> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
> Trivial comment inline.
>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
>
>> ---
>>  backends/iommufd.c                 | 6 +++++-
>>  hw/arm/smmuv3-accel.c              | 3 ++-
>>  hw/vfio/iommufd.c                  | 7 +++++--
>>  include/system/host_iommu_device.h | 2 ++
>>  include/system/iommufd.h           | 3 ++-
>>  5 files changed, 16 insertions(+), 5 deletions(-)
> ...
>
>> diff --git a/include/system/host_iommu_device.h b/include/system/host_iommu_device.h
>> index ab849a4a82..c6a2a3899a 100644
>> --- a/include/system/host_iommu_device.h
>> +++ b/include/system/host_iommu_device.h
>> @@ -29,6 +29,7 @@ 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)
> Blank line here to match local style. 
>
>> + * @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
>> @@ -37,6 +38,7 @@ 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 e852193f35..d3efcffc45 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, ram_addr_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 *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,