Re: [PATCH 2.6.25] module: allow ndiswrapper to use GPL-only symbols

Ingo Molnar
2008-03-03T10:58:47Z

* Pavel Roskin <proski@gnu.org> wrote:

> > btw., what are the technical reasons why ndiswrapper cannot be done
> > in userspace, much like the (wildly successful) FUSE concept?
>
> ndiswrapper contains essentially two drivers in one - PCI and USB.
> The PCI driver uses DMA, which should be a strong argument for keeping
> it in the kernel.

how exactly does it use DMA - how does it allocate the memory it later
on DMAs into, and how does it typically program that DMA target - is
there any control over that in the NDIS protocol - or will NDIS drivers
just write random addresses to the mmio space and then the hardware does
DMA to/from those addresses? [without the NDIS framework having any
knowledge about the encoding of those bits?]

on modern hardware it might even be possible to jail an ndiswrapper
driver to its own pages via the IOMMU.

Ingo