Re: [PATCH] iommu: amd/intel: Remove multifunction assumption around grouping

[Joerg Roedel <joro@8bytes.org>]

On Thu, May 30, 2013 at 12:39:18PM -0600, Alex Williamson wrote:
> If a device is multifunction and does not have ACS enabled then we
> assume that the entire package lacks ACS and use function 0 as the
> base of the group.  The PCIe spec however states that components are
> permitted to implement ACS on some, none, or all of their applicable
> functions.  It's therefore conceivable that function 0 may be fully
> independent and support ACS while other functions do not.  Instead
> use the lowest function of the slot that does not have ACS enabled
> as the base of the group.  This may be the current device, which is
> intentional.  So long as we use a consistent algorithm, all the
> non-ACS functions will be grouped together and ACS functions will
> get separate groups.
> 
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
>  drivers/iommu/amd_iommu.c   |   25 +++++++++++++++++++------
>  drivers/iommu/intel-iommu.c |   25 +++++++++++++++++++------

Didn't really fit into any of my existing branches. Applied it to
x86/vt-d because it is probably not worth creating a new x86-specific
branch just for this patch.

Thanks,

	Joerg