lkml.org 
[lkml]   [2013]   [Apr]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu implementation.
Date


> -----Original Message-----
> From: Alex Williamson [mailto:alex.williamson@redhat.com]
> Sent: Wednesday, April 03, 2013 11:32 PM
> To: Joerg Roedel
> Cc: Sethi Varun-B16395; Yoder Stuart-B08248; Wood Scott-B07421;
> iommu@lists.linux-foundation.org; linuxppc-dev@lists.ozlabs.org; linux-
> kernel@vger.kernel.org; galak@kernel.crashing.org;
> benh@kernel.crashing.org
> Subject: Re: [PATCH 5/5 v11] iommu/fsl: Freescale PAMU driver and iommu
> implementation.
>
> On Tue, 2013-04-02 at 18:18 +0200, Joerg Roedel wrote:
> > Cc'ing Alex Williamson
> >
> > Alex, can you please review the iommu-group part of this patch?
>
> Sure, it looks pretty reasonable. AIUI, all PCI devices are below some
> kind of host bridge that is either new and supports partitioning or old
> and doesn't. I don't know if that's a visibility or isolation
> requirement, perhaps PCI ACS-ish. In the new host bridge case, each
> device gets a group. This seems not to have any quirks for multifunction
> devices though. On AMD and Intel IOMMUs we test multifunction device ACS
> support to determine whether all the functions should be in the same
> group. Is there any reason to trust multifunction devices on PAMU?
>
[Sethi Varun-B16395] In the case where we can partition endpoints we can distinguish transactions based on the bus,device,function number combination. This support is available in the PCIe controller (host bridge).

> I also find it curious what happens to the iommu group of the host
> bridge. In the partitionable case the host bridge group is removed, in
> the non-partitionable case the host bridge group becomes the group for
> the children, removing the host bridge. It's unique to PAMU so far that
> these host bridges are even in an iommu group (x86 only adds pci
> devices), but I don't see it as necessarily wrong leaving it in either
> scenario. Does it solve some problem to remove them from the groups?
> Thanks,
[Sethi Varun-B16395] The PCIe controller isn't a partitionable entity, it would always be owned by the host.

-Varun

\
 
 \ /
  Last update: 2013-04-04 15:42    [W:0.247 / U:3.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site