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Date:   Fri, 28 Aug 2020 15:46:39 +0200
From:   "jroedel@suse.de" <jroedel@suse.de>
To:     "Deucher, Alexander" <Alexander.Deucher@amd.com>
Cc:     "Kuehling, Felix" <Felix.Kuehling@amd.com>,
        Joerg Roedel <joro@8bytes.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "Huang, Ray" <Ray.Huang@amd.com>,
        "Koenig, Christian" <Christian.Koenig@amd.com>,
        "Lendacky, Thomas" <Thomas.Lendacky@amd.com>,
        "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] iommu/amd: Fix IOMMUv2 devices when SME is active
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On Wed, Aug 26, 2020 at 03:25:58PM +0000, Deucher, Alexander wrote:
> > Alex, do you know if anyone has tested amdgpu on an APU with SME
> > enabled? Is this considered something we support?
> 
> It's not something we've tested.  I'm not even sure the GPU portion of
> APUs will work properly without an identity mapping.  SME should work
> properly with dGPUs however, so this is a proper fix for them.  We
> don't use the IOMMUv2 path on dGPUs at all.

Is it possible to make the IOMMUv2 paths optional on iGPUs as well when
SME is active (or better, when the GPU is not identity mapped)?

Regards,

	Joerg