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
