[PATCH] Support PCIe Alternative RID Interpretation (ARI)

[Ryan Stone]

On Sun, Mar 30, 2014 at 10:29 AM, Konstantin Belousov
<kostikbel at gmail.com> wrote:
>> http://people.freebsd.org/~rstone/patches/ari/0002-Re-implement-the-DMAR-I-O-MMU-code-in-terms-of-PCI-R.patch
>
> I like this patch.
>
> One, trivial note, you do not need () there:
> +       ctxp += (ctx->rid & 0xff);
>

Done.

Unfortunately I had to re-write it a bit to account for the changes in
r263306.  Mostly it was trivial, but there's one thing that I wasn't
sure how best to handle.  busdma_dmar.c currently calls
dmar_bus_dma_is_dev_disabled with the bus/slot/function provided by
dmar_get_requestor.  That no longer works now that I've made the code
be based on RIDs.  What the patch currently does is use the
bus/slot/function from the requester device.  I think that's a little
cleaner anyway because in one case the current code fakes up a slot
and function.  Using those values in the UI for forcing DMAR off for a
device feels wrong to me (and difficult to document).  However, my
behaviour of forcing users to manually walk up the PCI tree to find
the PCIe-PCI bridge is not really all that much better.  If you have
ideas here please let me know.

The current version of the patch is in the same location.