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Subject: Re: [RFC] /dev/ioasid uAPI proposal
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     "Tian, Kevin" <kevin.tian@intel.com>,
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        David Gibson <david@gibson.dropbear.id.au>,
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From:   "Enrico Weigelt, metux IT consult" <lkml@metux.net>
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Date:   Tue, 8 Jun 2021 12:43:38 +0200
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On 04.06.21 14:30, Jason Gunthorpe wrote:

Hi,

> Containers already needed to do this today. Container orchestration is
> hard.

Yes, but I hate to see even more work upcoming here.

> Yes, /dev/ioasid shouldn't do anything unless you have a device to
> connect it with. In this way it is probably safe to stuff it into
> every container.

Okay, if we can guarantee that, I'm completely fine.

>>> Having FDs spawn other FDs is pretty ugly, it defeats the "everything
>>> is a file" model of UNIX.
>>
>> Unfortunately, this is already defeated in many other places :(
>> (I'd even claim that ioctls already break it :p)
> 
> I think you are reaching a bit :)
> 
>> It seems your approach also breaks this, since we now need to open two
>> files in order to talk to one device.
> 
> It is two devices, thus two files.

Two separate real (hardware) devices or just two logical device nodes ?


--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
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