Re: [PATCH v3 00/15] iommu: Retire bus_set_iommu()

Niklas Schnelle
2022-07-08T08:17:59Z

On Tue, 2022-07-05 at 18:08 +0100, Robin Murphy wrote:
> v2: https://lore.kernel.org/linux-iommu/cover.1650890638.git.robin.murphy@arm.com/
>
> Hi all,
>
> Here's v3, now with working x86! Having finally made sense of how I
> broke Intel, I've given AMD the same fix by inspection. I'm still not
> 100% sure about s390, but it looks like it should probably be OK since
> it seems to register an IOMMU instance for each PCI device (?!) before
> disappearing into PCI hotplug code, wherein I assume we should never see
> a PCI device appear without its IOMMU already registered.

Yes, this is a bit unusual as our PCI architecture doesn't really have
a notion of an IOMMU device only of I/O translation tables. These are
then registered per PCI function. PCI functions may share I/O
translation tables and thus DMA address spaces but this is not done at
the moment. As Matt already mentioned we do need a small change for
this patch series. Since that was still mangled in his mail for me I
just replied with that using "git send-email". With Matt's patch
applied I can confirm that this works fine for us and does look like a
useful simplification. So feel free to add my

Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>