Re: [Spice-devel] [RFC PATCH 1/1] Add a usbredir kernel module to remotely connect USB devices over IP.

Jeremy White
2015-07-06T20:15:07Z

On 07/06/2015 03:20 AM, Oliver Neukum wrote:
> On Fri, 2015-07-03 at 10:51 +0200, Krzysztof Opasiak wrote:
>> Doesn't we have the same problem with functionfs/gadgetfs and
>> dummy_hcd?
>> Or with fuse?
>>
>> It's a very generic problem for all "virtualized devices" and it is
>> known for quite a long time. This is why many tutorials about swap
>> warns
>> that swap should be set up only on real block devices which are fully
>> served in kernel.
>
> Indeed. But the point is that it isn't limited to swap. As you as
> a page needs to be laundered the problem exists.
> Mmapping a file for write (non private) is enough.

I'm persuaded to avoid user space in the core design.

Anything else fundamental to usbip that should inform the design of a
usbredir driver? usbip appears to be based off a 2004 vintage of
dummy_hcd. I'll look thoughtfully at the current dummy_hcd; please let
me know if there is anything else I should consider.

Cheers,

Jeremy