[PATCH v2 0/8] Host1x context isolation support

Mikko Perttunen
2021-09-16T14:37:04Z

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