On Sun, Oct 06, 2024 at 10:34:19PM +0300, Dmitry Baryshkov wrote: > 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. > I believe, drivers/remoteproc/qcom_q6v5_adsp.c does not follow TZ's PAS method (Secure) of handling remoteproc that may be the reason it has been kept separately from drivers/remoteproc/qcom_q6v5_pas.c . If we keep this implementation align with current PAS driver we would acheive more code reusability with less code change. However, I am not against, if we want to keep this as separate driver with qcom_q6v5_pas_common.c shared between the current pas driver with QHEE vs this implementation with non-QHEE. -Mukesh > > > > - 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
