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Message-ID: <r4zkfioctmlatxkb4lqmfc7vk7cdenenihoicq2k37wvxeihss@gtkzxr26p6ei>
Date: Sun, 6 Oct 2024 22:34:19 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Mukesh Ojha <quic_mojha@...cinc.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
Mathieu Poirier <mathieu.poirier@...aro.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
Konrad Dybcio <konradybcio@...nel.org>, Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/6] Peripheral Image Loader support for Qualcomm SoCs
On Sat, Oct 05, 2024 at 02:53:53AM GMT, Mukesh Ojha wrote:
> Qualcomm is looking to enable remote processors on the SA8775p SoC
> running KVM Linux host and is currently trying to figure out an
> upstream-compatible solution for the IOMMU translation scheme problem it
> is facing when SoCs running with KVM. This issue arises due to
> differences in how IOMMU translation is currently handled on SoCs
> running Qualcomm EL2 hypervisor(QHEE) where IOMMU translation for any
> device is completely owned by it and the other issue is that remote
> processors firmware does not contain resource table where these IOMMU
> configuration setting will be present.
>
> Qualcomm SoCs running with the QHEE(EL2) have been utilizing the
> Peripheral Authentication Service (PAS) from its TrustZone (TZ) firmware
> to securely authenticate and reset via a single SMC call
> _auth_and_reset_. This call first gets trapped to QHEE, which then
> makes a call to TZ for authentication. Once it is done, the call returns
> to QHEE, which sets up the IOMMU translation scheme for these remote
> processors and later brings them out of reset. The design of the
> Qualcomm EL2 hypervisor dictates that the Linux host OS running at EL1
> is not allowed to set up IOMMU translation for remote processors,
> and only a single stage is being configured for them.
>
> To make the remote processors’ bring-up (PAS) sequence
> hypervisor-independent, the auth_and_reset SMC call is now entirely
> handled by TZ. However, the problem of IOMMU handling still remains with
> the KVM host, which has no knowledge of the remote processors’ IOMMU
> configuration.
>
> We have looked up one approach where SoC remoteproc device tree could
> contain resources like iommus for remoteproc carveout and qcom,devmem
> specific binding for device memory needed for remoteproc and these
> properties are optional and will only be overlaid by the firmware if it
> is running with non-QHEE based hypervisor like KVM.
Can you follow the approach that has been implemented for existing
systems (ChromeOS) not using QHEE? See drivers/remoteproc/qcom_q6v5_adsp.c
If this approach can not be used, please describe why.
>
> - Patch 1/6 adds the iommus and qcom,devmem binding for PAS common yaml.
> - Patch 2/6 and 3/6 add helper function to IOMMU map and unmap carveout
> and device memory region.
> - Patch 4/6 adds a function to parse individual field of qcom,devmem property.
> - Patch 5/6 add helpers to create/destroy SHM bridge for remoteproc
> carveout and to get memory from tzmem SHM bridge pool for remoteproc
> firmware metadata.
> - Patch 6/6 enable all the required support to enable remoteproc for
> non-QHEE hypervisor based systems like KVM host via parsing the iommus
> properties and mapping/unmapping carveout and device memory based on
> it.
>
> Komal Bajaj (1):
> remoteproc: qcom: Add iommu map_unmap helper function
>
> Mukesh Ojha (2):
> remoteproc: qcom: Add support of SHM bridge to enable memory
> protection
> remoteproc: qcom: Enable map/unmap and SHM bridge support
>
> Shiraz Hashim (3):
> dt-bindings: remoteproc: qcom,pas-common: Introduce iommus and
> qcom,devmem property
> remoteproc: qcom: Add helper function to support IOMMU devmem
> translation
> remoteproc: qcom: Add support to parse qcom,devmem property
>
> .../bindings/remoteproc/qcom,pas-common.yaml | 42 +++++
> .../bindings/remoteproc/qcom,sa8775p-pas.yaml | 20 +++
> drivers/firmware/qcom/qcom_scm.c | 29 +++-
> drivers/firmware/qcom/qcom_tzmem.c | 14 +-
> drivers/remoteproc/qcom_common.c | 148 ++++++++++++++++++
> drivers/remoteproc/qcom_common.h | 38 +++++
> drivers/remoteproc/qcom_q6v5_pas.c | 140 ++++++++++++++++-
> include/linux/firmware/qcom/qcom_scm.h | 1 +
> include/linux/firmware/qcom/qcom_tzmem.h | 10 ++
> 9 files changed, 423 insertions(+), 19 deletions(-)
>
> --
> 2.34.1
>
--
With best wishes
Dmitry
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