Re: UIO: missing resource mapping

From: Dominic Eschweiler
Date: Fri Jul 13 2012 - 04:09:25 EST


Am Freitag, den 13.07.2012, 02:16 +0300 schrieb Michael S. Tsirkin:
> My concern was people will ask for more and more stuff that pci
> sysfs already has.
> If we do add these is there a way to not duplicate code from pci?

I have some concerns about the placing for the BAR mapping code inside
the kernel. The point is, that sysfs currently makes it possible to map
BARs of all card which are handled by any driver. This is fine in case
of UIO, because it is intended that a user-space program maps BARs, but
it is also possible to map BARs that are already handle by a kernel
driver. It i therefore possible to jam the system by confusing sysfs
entries.

I don't know which implications this has, but I would move the BAR
mapping capabilities completely to UIO. This should ensure that only
BARs can be mapped, which are handled by UIO and no other kernel-space
driver.

--
GruÃ
Dominic

Frankfurt Institute for Advanced Studies (FIAS)
Ruth-Moufang-StraÃe 1
D-60438 Frankfurt am Main
Germany

Phone: +49 69 79844114

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