Re: [PATCH v2 05/10] vfio: Implement get_host_iommu_info() callback

["Cédric Le Goater" <clg@redhat.com>]

On 4/8/24 10:12, Zhenzhong Duan wrote:
> Utilize iova_ranges to calculate host IOMMU address width and
> package it in HIOD_LEGACY_INFO for vIOMMU usage.
> 
> HIOD_LEGACY_INFO will be used by both VFIO and VDPA so declare
> it in host_iommu_device.h.
> 
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>   include/sysemu/host_iommu_device.h | 10 ++++++++++
>   hw/vfio/container.c                | 24 ++++++++++++++++++++++++
>   2 files changed, 34 insertions(+)
> 
> diff --git a/include/sysemu/host_iommu_device.h b/include/sysemu/host_iommu_device.h
> index 22ccbe3a5d..beb8be8231 100644
> --- a/include/sysemu/host_iommu_device.h
> +++ b/include/sysemu/host_iommu_device.h
> @@ -16,4 +16,14 @@ struct HostIOMMUDeviceClass {
>       int (*get_host_iommu_info)(HostIOMMUDevice *hiod, void *data, uint32_t len,
>                                  Error **errp);
>   };
> +
> +/*
> + * Define the format of host IOMMU related info that current VFIO
> + * or VDPA can privode to vIOMMU.
> + *
> + * @aw_bits: Host IOMMU address width. 0xff if no limitation.
> + */
> +typedef struct HIOD_LEGACY_INFO {

Please use CamelCase names.

> +    uint8_t aw_bits;
> +} HIOD_LEGACY_INFO;
>   #endif
> diff --git a/hw/vfio/container.c b/hw/vfio/container.c
> index 44018ef085..ba0ad4a41b 100644
> --- a/hw/vfio/container.c
> +++ b/hw/vfio/container.c
> @@ -1143,8 +1143,32 @@ static void vfio_iommu_legacy_class_init(ObjectClass *klass, void *data)
>       vioc->pci_hot_reset = vfio_legacy_pci_hot_reset;
>   };
>   
> +static int hiod_legacy_vfio_get_host_iommu_info(HostIOMMUDevice *hiod,
> +                                                void *data, uint32_t len,
> +                                                Error **errp)
> +{
> +    VFIODevice *vbasedev = HIOD_LEGACY_VFIO(hiod)->vdev;
> +    /* iova_ranges is a sorted list */
> +    GList *l = g_list_last(vbasedev->bcontainer->iova_ranges);
> +    HIOD_LEGACY_INFO *info = data;
> +
> +    assert(sizeof(HIOD_LEGACY_INFO) <= len);
> +
> +    if (l) {
> +        Range *range = l->data;
> +        info->aw_bits = find_last_bit(&range->upb, BITS_PER_LONG) + 1;

There is a comment in range.h saying:

     /*
      * Do not access members directly, use the functions!

Please introduce a new helper.


Thanks,

C.



> +    } else {
> +        info->aw_bits = 0xff;
> +    }
> +
> +    return 0;
> +}
> +
>   static void hiod_legacy_vfio_class_init(ObjectClass *oc, void *data)
>   {
> +    HostIOMMUDeviceClass *hioc = HOST_IOMMU_DEVICE_CLASS(oc);
> +
> +    hioc->get_host_iommu_info = hiod_legacy_vfio_get_host_iommu_info;
>   };
>   
>   static const TypeInfo types[] = {