RE: [PATCH v7 00/27] vfio: Adopt iommufd

[Duan, Zhenzhong]

>-----Original Message-----
>From: Cédric Le Goater <clg@redhat.com>
>Sent: Wednesday, November 22, 2023 1:23 AM
>Subject: Re: [PATCH v7 00/27] vfio: Adopt iommufd
>
>Hello Zhenzhong
>
>On 11/21/23 09:43, Zhenzhong Duan wrote:
>> Hi,
>>
>> Thanks all for giving guides and comments on previous series, this is
>> the remaining part of the iommufd support.
>>
>> Besides suggested changes in v6, I'd like to highlight two changes
>> for final review:
>> 1. Instantiate can_be_deleted callback to fix race where iommufd object
>>     can be deleted before vfio device
>> 2. After careful re-thinking, I'd like to follow Nicolin's suggestion in v5,
>>     remove is_ioas check which indeed looks heavy just for tracepoint.
>>     In fact we can get corresponding info by looking over trace context.
>>
>> PATCH 1: Introduce iommufd object
>> PATCH 2-9: add IOMMUFD container and cdev support
>> PATCH 10-17: fd passing for cdev and linking to IOMMUFD
>> PATCH 18: make VFIOContainerBase parameter const
>> PATCH 19-21: Compile out for IOMMUFD for arm, s390x and x86
>> PATCH 22-26: vfio device init code cleanup
>> PATCH 27: add iommufd doc
>>
>>
>> We have done wide test with different combinations, e.g:
>> - PCI device were tested
>> - FD passing and hot reset with some trick.
>> - device hotplug test with legacy and iommufd backends
>> - with or without vIOMMU for legacy and iommufd backends
>> - divices linked to different iommufds
>> - VFIO migration with a E800 net card(no dirty sync support) passthrough
>> - platform, ccw and ap were only compile-tested due to environment limit
>> - test mdev pass through with mtty and mix with real device and different BE
>> - test iommufd object hotplug/unplug and mix with vfio device plug/unplug
>>
>> Given some iommufd kernel limitations, the iommufd backend is
>> not yet fully on par with the legacy backend w.r.t. features like:
>> - p2p mappings (you will see related error traces)
>> - dirty page sync
>> - and etc.
>>
>>
>> qemu code:
>https://github.com/yiliu1765/qemu/commits/zhenzhong/iommufd_cdev_v7
>> Based on vfio-next, commit id: c487fb8a50
>
>The series is pushed on top of vfio-next in the vfio-8.2 tree :
>
>   https://github.com/legoater/qemu/commits/vfio-8.2
>
>with a little extra to deal with a PPC build failure.

Thanks Cédric. That's strange I didn't see this failure on my env
which has CONFIG_VFIO_PCI enabled by default for PPC.

BRs.
Zhenzhong