Re: [PATCH v6 07/19] vfio/container: Implement HostIOMMUDeviceClass::realize() handler

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

Hi Zhenzhong,

On 6/3/24 08:10, Zhenzhong Duan wrote:
> Utilize range_get_last_bit() to get host IOMMU address width and
> package it in HostIOMMUDeviceCaps for query with .get_cap().
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/vfio/container.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
>
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index c4fca2dfca..48800fe92f 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -1136,6 +1136,31 @@ static void vfio_iommu_legacy_class_init(ObjectClass *klass, void *data)
>      vioc->pci_hot_reset = vfio_legacy_pci_hot_reset;
>  };
>  
> +static bool hiod_legacy_vfio_realize(HostIOMMUDevice *hiod, void *opaque,
> +                                     Error **errp)
> +{
> +    VFIODevice *vdev = opaque;
> +    /* iova_ranges is a sorted list */
> +    GList *l = g_list_last(vdev->bcontainer->iova_ranges);
> +
> +    /* Only support query HOST_IOMMU_DEVICE_CAP_AW_BITS with legacy backend */
I don't get the comment as HOST_IOMMU_DEVICE_CAP_AW_BITS support seems
to be introduced in [PATCH v6 11/19] backends/iommufd: Implement
HostIOMMUDeviceClass::get_cap() handler
> +    if (l) {
> +        Range *range = l->data;
> +        hiod->caps.aw_bits = range_get_last_bit(range) + 1;
> +    } else {
> +        hiod->caps.aw_bits = 0xff;
why this value?
> +    }
> +
> +    return true;
> +}
> +
> +static void hiod_legacy_vfio_class_init(ObjectClass *oc, void *data)
> +{
> +    HostIOMMUDeviceClass *hioc = HOST_IOMMU_DEVICE_CLASS(oc);
> +
> +    hioc->realize = hiod_legacy_vfio_realize;
> +};
> +
>  static const TypeInfo types[] = {
>      {
>          .name = TYPE_VFIO_IOMMU_LEGACY,
> @@ -1144,6 +1169,7 @@ static const TypeInfo types[] = {
>      }, {
>          .name = TYPE_HOST_IOMMU_DEVICE_LEGACY_VFIO,
>          .parent = TYPE_HOST_IOMMU_DEVICE,
> +        .class_init = hiod_legacy_vfio_class_init,
>      }
>  };
>  

Thanks

Eric