RE: [PATCH v1 15/22] Add iommufd configure option

[Duan, Zhenzhong]

>-----Original Message-----
>From: Jason Gunthorpe <jgg@nvidia.com>
>Sent: Thursday, September 21, 2023 2:20 AM
>Subject: Re: [PATCH v1 15/22] Add iommufd configure option
>
>On Wed, Sep 20, 2023 at 12:17:24PM -0600, Alex Williamson wrote:
>
>> > The iommufd design requires one open of the /dev/iommu to be shared
>> > across all the vfios.
>>
>> "requires"?  It's certainly of limited value to have multiple iommufd
>> instances rather than create multiple address spaces within a single
>> iommufd, but what exactly precludes an iommufd per device if QEMU, or
>> any other userspace so desired?  Thanks,
>
>From the kernel side requires is too strong I suppose
>
>Not sure about these qemu patches though?

I had ever tested with multiple IOMMUFDs and mix of IOMMUFD/legacy BE linking 
to different VFIO devices with this series,  all works fine.

Thanks
Zhenzhong