On 23.07.26 16:38, Jorge Ramirez-Ortiz via U-Boot wrote:
> OP-TEE secure storage (CFG_RPMB_FS) relies on an RPMB partition, but
> U-Boot's OP-TEE RPMB supplicant only speaks the legacy single-command
> interface, which is bound to eMMC. SoCs that are UFS-only and have no
> eMMC (for example the Qualcomm SA8775P) therefore cannot back OP-TEE
> secure storage from U-Boot today. This series adds that support.
> 
> It introduces the transport-agnostic OP-TEE RPMB "subsystem" interface
> (PROBE_RESET / PROBE_NEXT / FRAMES), where the normal world enumerates
> the RPMB device and reports its kind, size and CID, then carries the
> signed frames. The legacy eMMC supplicant is preserved unchanged, only
> renamed to rpmb_emmc.c, with the new UFS backend added as a separate
> rpmb_ufs.c; the two are mutually exclusive via Kconfig (SUPPORT_UFS_RPMB
> depends on !SUPPORT_EMMC_RPMB) because the OP-TEE supplicant handles a
> single RPMB transport. The subsystem interface is UFS-only for now; eMMC
> can be migrated onto it later as the legacy path is retired.
> 

Just stumbled over this. Not sure if you saw [1] already. Our series
collide, and while yours lacks RPMB TA enumeration (to enable fTPM
e.g.), mine is based on the the in-tree emmc-only core. How to resolve
that best? Establish a common optee/rpmb.c for now so that the service
enumeration can be shared by both?

> On top of that it adds a UFS RPMB transport that moves JEDEC RPMB frames
> to and from the RPMB Well-Known LUN using SCSI SECURITY PROTOCOL IN/OUT.
> The per-region 16-byte CID is derived by BLAKE2b-hashing the exact
> device-id string the Linux kernel builds (ufshcd_create_device_id()
> plus a "-R<region>" suffix), so OP-TEE derives an RPMB key that matches
> the one Linux would use.
> 
> The first patch is a standalone UFS descriptor fix the RPMB path depends
> on (UTF-16BE string decoding); the transport patches also include a
> power-on UNIT ATTENTION retry and a DMA-alignment bounce for the RPMB
> WLUN.
> 
> Note: reading UFS descriptors reliably also requires the descriptor
> data-segment cache-invalidation fix, which has already been posted and
> merged separately, so this series is based on top of it.
> 
> Tested on the Qualcomm IQ-9075-EVK (SA8775P): OP-TEE with CFG_RPMB_FS
> programs the RPMB key through U-Boot and reads/writes secure-storage
> objects, with the derived CID matching the Linux UFS device_id ABI.

Looks like the QEMU model for UFS is still lacking RPMB support. Did you
happen to have a look if the eMMC bits could be reused for that? We are
doing most of the security stack integration tests via QEMU now,
including OTP key deployments - you would need a lot of new hardware
otherwise.

Jan

[1]
https://lore.kernel.org/u-boot/[email protected]/

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Siemens AG, Foundational Technologies
Linux Expert Center

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