From: Dmitry Osipenko <digetx@gmail.com>
To: Joerg Roedel <joro@8bytes.org>, Rob Herring <robh+dt@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Thierry Reding <thierry.reding@gmail.com>,
Jon Hunter <jonathanh@nvidia.com>,
Mikko Perttunen <cyndis@kapsi.fi>,
Frank Rowand <frowand.list@gmail.com>,
bskeggs@redhat.com, Russell King <linux@armlinux.org.uk>,
Catalin Marinas <catalin.marinas@arm.com>,
kwizart@gmail.com, devicetree@vger.kernel.org,
nouveau@lists.freedesktop.org,
Linux IOMMU <iommu@lists.linux-foundation.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
linux-tegra@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU
Date: Fri, 27 Jul 2018 23:02:01 +0300 [thread overview]
Message-ID: <4850389.K9ByBxYttl@dimapc> (raw)
In-Reply-To: <20180727183134.GD6738@8bytes.org>
On Friday, 27 July 2018 21:31:34 MSK Joerg Roedel wrote:
> On Fri, Jul 27, 2018 at 11:13:31AM -0600, Rob Herring wrote:
> > I don't follow why we need a property rather than being implied by the
> > device's (the GPU) compatible string.
>
> There might be devices where either setup works, with or without IOMMU
> translation, and the firmware can set the property depending on whether
> the user wants more performance or more security.
>
> If we have a whitelist in the kernel this gets more complicated, we
> probably need additional kernel-parameters to overwrite those whitelist
> entries. Having a property in the device-tree seems to be a better way
> here, imho.
IIUC, device-tree should be considered to be "written in stone" for a consumer
device and hence firmware property isn't something that could be easily
changed. The kernel-parameter will be much more universal. Anyway the global
whitelisting should be a different topic for discussion, right now we need a
kind of private whitelisting that is internal to kernel.
next prev parent reply other threads:[~2018-07-27 20:02 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-26 23:16 [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 1/6] driver core: Add option for disabling of backing devices DMA " Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 2/6] of/device: Don't back devices DMA with IOMMU if that's undesired by driver Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 3/6] drm/tegra: Avoid implicit DMA backing with IOMMU Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 4/6] gpu: host1x: " Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 5/6] drm/nouveau: tegra: Universally avoid " Dmitry Osipenko
2018-07-26 23:16 ` [RFC PATCH v1 6/6] Revert "drm/nouveau: tegra: Detach from ARM DMA/IOMMU mapping" Dmitry Osipenko
2018-07-27 8:25 ` [RFC PATCH v1 0/6] Resolve unwanted DMA backing with IOMMU Joerg Roedel
2018-07-27 9:03 ` Will Deacon
2018-07-27 14:10 ` Dmitry Osipenko
2018-07-27 14:20 ` Joerg Roedel
2018-07-27 17:13 ` Rob Herring
2018-07-27 18:31 ` Joerg Roedel
2018-07-27 20:02 ` Dmitry Osipenko [this message]
2018-07-27 16:02 ` Robin Murphy
2018-07-27 17:03 ` Jordan Crouse
2018-07-27 17:16 ` Dmitry Osipenko
2018-07-28 11:40 ` Dmitry Osipenko
2018-08-02 18:24 ` Dmitry Osipenko
2018-08-03 15:43 ` Robin Murphy
2018-08-03 17:00 ` Jordan Crouse
2018-08-15 19:56 ` Dmitry Osipenko
2018-08-16 17:23 ` Robin Murphy
2018-09-20 17:09 ` Dmitry Osipenko
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