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Subject: Re: [RFC PATCH v3 8/8] vfio: Add nested IOPF support
To:     Lu Baolu <baolu.lu@linux.intel.com>,
        Alex Williamson <alex.williamson@redhat.com>
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 <9daf8877-a538-2d19-f548-b00ea6f127df@linux.intel.com>
From:   Shenming Lu <lushenming@huawei.com>
Message-ID: <8b6e5abd-d965-2331-7af3-08bef399af0f@huawei.com>
Date:   Tue, 1 Jun 2021 12:36:15 +0800
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On 2021/5/27 19:18, Lu Baolu wrote:
> Hi Shenming and Alex,
> 
> On 5/27/21 7:03 PM, Shenming Lu wrote:
>>> I haven't fully read all the references, but who imposes the fact that
>>> there's only one fault handler per device?  If type1 could register one
>>> handler and the vfio-pci bus driver another for the other level, would
>>> we need this path through vfio-core?
>> If we could register more than one handler per device, things would become
>> much more simple, and the path through vfio-core would not be needed.
>>
>> Hi Baolu,
>> Is there any restriction for having more than one handler per device?
>>
> 
> Currently, each device could only have one fault handler. But one device
> might consume multiple page tables. From this point of view, it's more
> reasonable to have one handler per page table.

Sounds good to me. I have pointed it out in the IOASID uAPI proposal. :-)

Thanks,
Shenming

> 
> Best regards,
> baolu
> .