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Date: Mon, 5 Dec 2022 11:53:16 +0100
From: Joerg Roedel <joro@8bytes.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: iommu@lists.linux.dev, Maxime Ripard <maxime@cerno.tech>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
	Robin Murphy <robin.murphy@arm.com>,
	Samuel Holland <samuel@sholland.org>, Chen-Yu Tsai <wens@csie.org>,
	Will Deacon <will@kernel.org>, Joerg Roedel <jroedel@suse.de>
Subject: Re: [PATCH] iommu/sun50i: Remove IOMMU_DOMAIN_IDENTITY
Message-ID: <Y43NnDhS8saBM/JP@8bytes.org>
References: <0-v1-97f0adf27b5e+1f0-s50_identity_jgg@nvidia.com>
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In-Reply-To: <0-v1-97f0adf27b5e+1f0-s50_identity_jgg@nvidia.com>

On Mon, Nov 28, 2022 at 10:06:28AM -0400, Jason Gunthorpe wrote:
> This driver treats IOMMU_DOMAIN_IDENTITY the same as UNMANAGED, which
> cannot possibly be correct.
> 
> UNMANAGED domains are required to start out blocking all DMAs. This seems
> to be what this driver does as it allocates a first level 'dt' for the IO
> page table that is 0 filled.
> 
> Thus UNMANAGED looks like a working IO page table, and so IDENTITY must be
> a mistake. Remove it.
> 
> Fixes: 4100b8c229b3 ("iommu: Add Allwinner H6 IOMMU driver")
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Applied, thanks.