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Message-ID: <44c823d7c9ab15579d30734761200c0a6ed44a6f.camel@linux.ibm.com>
Subject: Re: [PATCH v3 00/15] iommu: Retire bus_set_iommu()
From:   Niklas Schnelle <schnelle@linux.ibm.com>
To:     Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org,
        Matthew Rosato <mjrosato@linux.ibm.com>
Cc:     will@kernel.org, iommu@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, baolu.lu@linux.intel.com,
        suravee.suthikulpanit@amd.com, vasant.hegde@amd.com,
        mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Fri, 08 Jul 2022 10:17:30 +0200
In-Reply-To: <cover.1657034827.git.robin.murphy@arm.com>
References: <cover.1657034827.git.robin.murphy@arm.com>
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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>