RE: [PATCH v1 13/22] vfio: Add base container

[Duan, Zhenzhong]

Hi Eric,

>-----Original Message-----
>From: Eric Auger <eric.auger@redhat.com>
>Sent: Thursday, September 21, 2023 1:31 AM
>Subject: Re: [PATCH v1 13/22] vfio: Add base container
>
>Hi Zhenzhong,
>
>On 9/19/23 19:23, Cédric Le Goater wrote:
>> On 8/30/23 12:37, Zhenzhong Duan wrote:
>>> From: Yi Liu <yi.l.liu@intel.com>
>>>
>>> Abstract the VFIOContainer to be a base object. It is supposed to be
>>> embedded by legacy VFIO container and later on, into the new iommufd
>>> based container.
>>>
>>> The base container implements generic code such as code related to
>>> memory_listener and address space management. The VFIOContainerOps
>>> implements callbacks that depend on the kernel user space being used.
>>>
>>> 'common.c' and vfio device code only manipulates the base container with
>>> wrapper functions that calls the functions defined in
>>> VFIOContainerOpsClass.
>>> Existing 'container.c' code is converted to implement the legacy
>>> container
>>> ops functions.
>>>
>>> Below is the base container. It's named as VFIOContainer, old
>>> VFIOContainer
>>> is replaced with VFIOLegacyContainer.
>>
>> Usualy, we introduce the new interface solely, port the current models
>> on top of the new interface, wire the new models in the current
>> implementation and remove the old implementation. Then, we can start
>> adding extensions to support other implementations.
>>
>> spapr should be taken care of separatly following the principle above.
>> With my PPC hat, I would not even read such a massive change, too risky
>> for the subsystem. This path will need (much) further splitting to be
>> understandable and acceptable.
>We might split this patch by
>1) introducing VFIOLegacyContainer encapsulating the base VFIOContainer,
>without using the ops in a first place:
> common.c would call vfio_container_* with harcoded legacy
>implementation, ie. retrieving the legacy container with container_of.
>2) we would introduce the BE interface without using it.
>3) we would use the new BE interface
>
>Obviously this needs to be further tried out. If you wish I can try to
>split it that way ... Please let me know

Sure, thanks for your help, glad that I can cooperate with you to move
this series forward.
I just updated the branch which rebased to newest upstream for you to pick at 
https://github.com/yiliu1765/qemu/tree/zhenzhong/iommufd_cdev_v1_rebased 

Thanks
Zhenzhong