Re: [PATCH v6 05/12] vfio: Support for RamDiscardMgr in the !vIOMMU case

[Paolo Bonzini]

On 22/02/21 12:57, David Hildenbrand wrote:
> +static int vfio_sync_ram_discard_listener_dirty_bitmap(VFIOContainer 
> *container,
> +                                                   MemoryRegionSection 
> *section)
> +{
> +    RamDiscardMgr *rdm = memory_region_get_ram_discard_mgr(section->mr);
> +    RamDiscardMgrClass *rdmc = RAM_DISCARD_MGR_GET_CLASS(rdm);
> +    VFIORamDiscardListener tmp_vrdl, *vrdl = NULL;
> +
> +    QLIST_FOREACH(vrdl, &container->vrdl_list, next) {
> +        if (vrdl->mr == section->mr &&
> +            vrdl->offset_within_region == section->offset_within_region) {
> +            break;
> +        }
> +    }
> +
> +    if (!vrdl) {
> +        hw_error("vfio: Trying to sync missing RAM discard listener");
> +    }
> +
> +    tmp_vrdl = *vrdl;
> +    ram_discard_listener_init(&tmp_vrdl.listener,
> +                              vfio_ram_discard_notify_dirty_bitmap, NULL, 
> NULL);
> +    return rdmc->replay_populated(rdm, section->mr, &tmp_vrdl.listener);
> +}
> +

Can you explain why this is related to the sync_dirty_bitmap call?  This 
needs a comment in vfio_sync_dirty_bitmap.

Also, why can't you just pass vrdl to the call?

Paolo