Re: [RFC PATCH 2/2] vfio: Include no-iommu mode

[Avi Kivity <avi-VrcmuVmyx1hWk0Htik3J/w@public.gmane.org>]

On 10/12/2015 07:23 PM, Alex Williamson wrote:
>> Also, although you think the long option will set the bar high
>> enough it probably will not satisfy anyone. It is annoying enough, that
>> I would just carry a patch to remove it the silly requirement.
>> And the the people who believe
>> all user mode DMA is evil won't be satisfied either.
> I find that many users blindly follow howtos and only sometimes do they
> question the options if they sound scary enough.  So yeah, I would
> intend to make the option upstream sound scary enough for people to
> think twice about using it and maybe even read the description.  That
> still doesn't prevent pasting it into modprobe.d and forgetting about
> it.

I think we need to allow for packages to work with this.  I.e. drop 
files into config directories rather than require editing of config 
files.  I think this is mostly workable via modprobe.d.

(for our own use case, we don't require the extreme performance of many 
L2/L3 dpdk apps so we'll work with regular iommued vfio for bare-metal 
installations and ship prebuilt virtual machine images for clouds, so it 
doesn't matter that much to me).