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Message-ID: <91dddccd-a6c1-21b3-34d6-6a8082a386e7@nvidia.com>
Date: Tue, 14 Dec 2021 08:05:44 +0000
From: Jon Hunter <jonathanh@...dia.com>
To: joro@...tes.org, will@...nel.org, robh+dt@...nel.org,
robin.murphy@....com
Cc: linux-tegra@...r.kernel.org, dri-devel@...ts.freedesktop.org,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Mikko Perttunen <cyndis@...si.fi>,
Mikko Perttunen <mperttunen@...dia.com>,
thierry.reding@...il.com
Subject: Re: [PATCH v2 0/8] Host1x context isolation support
Hi all,
Still no response on this :-(
On 06/12/2021 09:55, Jon Hunter wrote:
> Will, Joerg, Rob,
>
> On 08/11/2021 10:36, Mikko Perttunen wrote:
>> On 9/16/21 5:32 PM, Mikko Perttunen wrote:
>>> Hi all,
>>>
>>> ***
>>> New in v2:
>>>
>>> Added support for Tegra194
>>> Use standard iommu-map property instead of custom mechanism
>>> ***
>>>
>>> this series adds support for Host1x 'context isolation'. Since
>>> when programming engines through Host1x, userspace can program in
>>> any addresses it wants, we need some way to isolate the engines'
>>> memory spaces. Traditionally this has either been done imperfectly
>>> with a single shared IOMMU domain, or by copying and verifying the
>>> programming command stream at submit time (Host1x firewall).
>>>
>>> Since Tegra186 there is a privileged (only usable by kernel)
>>> Host1x opcode that allows setting the stream ID sent by the engine
>>> to the SMMU. So, by allocating a number of context banks and stream
>>> IDs for this purpose, and using this opcode at the beginning of
>>> each job, we can implement isolation. Due to the limited number of
>>> context banks only each process gets its own context, and not
>>> each channel.
>>>
>>> This feature also allows sharing engines among multiple VMs when
>>> used with Host1x's hardware virtualization support - up to 8 VMs
>>> can be configured with a subset of allowed stream IDs, enforced
>>> at hardware level.
>>>
>>> To implement this, this series adds a new host1x context bus, which
>>> will contain the 'struct device's corresponding to each context
>>> bank / stream ID, changes to device tree and SMMU code to allow
>>> registering the devices and using the bus, as well as the Host1x
>>> stream ID programming code and support in TegraDRM.
>>>
>>> Device tree bindings are not updated yet pending consensus that the
>>> proposed changes make sense.
>>>
>>> Thanks,
>>> Mikko
>>>
>>> Mikko Perttunen (8):
>>> gpu: host1x: Add context bus
>>> gpu: host1x: Add context device management code
>>> gpu: host1x: Program context stream ID on submission
>>> iommu/arm-smmu: Attach to host1x context device bus
>>> arm64: tegra: Add Host1x context stream IDs on Tegra186+
>>> drm/tegra: falcon: Set DMACTX field on DMA transactions
>>> drm/tegra: vic: Implement get_streamid_offset
>>> drm/tegra: Support context isolation
>>>
>>> arch/arm64/boot/dts/nvidia/tegra186.dtsi | 12 ++
>>> arch/arm64/boot/dts/nvidia/tegra194.dtsi | 12 ++
>>> drivers/gpu/Makefile | 3 +-
>>> drivers/gpu/drm/tegra/drm.h | 2 +
>>> drivers/gpu/drm/tegra/falcon.c | 8 +
>>> drivers/gpu/drm/tegra/falcon.h | 1 +
>>> drivers/gpu/drm/tegra/submit.c | 13 ++
>>> drivers/gpu/drm/tegra/uapi.c | 34 ++++-
>>> drivers/gpu/drm/tegra/vic.c | 38 +++++
>>> drivers/gpu/host1x/Kconfig | 5 +
>>> drivers/gpu/host1x/Makefile | 2 +
>>> drivers/gpu/host1x/context.c | 174 ++++++++++++++++++++++
>>> drivers/gpu/host1x/context.h | 27 ++++
>>> drivers/gpu/host1x/context_bus.c | 31 ++++
>>> drivers/gpu/host1x/dev.c | 12 +-
>>> drivers/gpu/host1x/dev.h | 2 +
>>> drivers/gpu/host1x/hw/channel_hw.c | 52 ++++++-
>>> drivers/gpu/host1x/hw/host1x06_hardware.h | 10 ++
>>> drivers/gpu/host1x/hw/host1x07_hardware.h | 10 ++
>>> drivers/iommu/arm/arm-smmu/arm-smmu.c | 13 ++
>>> include/linux/host1x.h | 21 +++
>>> include/linux/host1x_context_bus.h | 15 ++
>>> 22 files changed, 488 insertions(+), 9 deletions(-)
>>> create mode 100644 drivers/gpu/host1x/context.c
>>> create mode 100644 drivers/gpu/host1x/context.h
>>> create mode 100644 drivers/gpu/host1x/context_bus.c
>>> create mode 100644 include/linux/host1x_context_bus.h
>>>
>>
>> IOMMU/DT folks, any thoughts about this approach? The patches that are
>> of interest outside of Host1x/TegraDRM specifics are patches 1, 2, 4,
>> and 5.
>
>
> Any feedback on this?
>
> Jon
>
--
nvpublic
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