Hi Jens, On Wed, 31 Jan 2024 at 23:14, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote: > > Hi, > > It's been a while since Shyam posted the last version [1] of this patch > set. I've pinged Shyam, but so far I've had no reply so I'm trying to make > another attempt with the RPMB subsystem. If Shyam has other changes in mind > than what I'm adding here I hope we'll find a way to cover that too. I'm > calling it version two of the patchset since I'm trying to address all > feedback on the previous version even if I'm starting a new thread. > > This patch set introduces a new RPMB subsystem, based on patches from [1], > [2], and [3]. The RPMB subsystem aims at providing access to RPMB > partitions to other kernel drivers, in particular the OP-TEE driver. A new > user space ABI isn't needed, we can instead continue using the already > present ABI when writing the RPMB key during production. > > I've added and removed things to keep only what is needed by the OP-TEE > driver. Since the posting of [3], there has been major changes in the MMC > subsystem so "mmc: block: register RPMB partition with the RPMB subsystem" > is in practice completely rewritten. > > With this OP-TEE can access RPMB during early boot instead of having to > wait for user space to become available as in the current design [4]. > This will benefit the efi variables [5] since we wont rely on userspace as > well as some TPM issues [6] that were solved. > > The OP-TEE driver finds the correct RPMB device to interact with by > iterating over available devices until one is found with a programmed > authentication matching the one OP-TEE is using. This enables coexisting > users of other RPMBs since the owner can be determined by who knows the > authentication key. > > I've put myself as a maintainer for the RPMB subsystem as I have an > interest in the OP-TEE driver to keep this in good shape. However, if you'd > rather see someone else taking the maintainership that's fine too. I'll > help keep the subsystem updated regardless. > > [1] https://lore.kernel.org/lkml/20230722014037.42647-1-shyamsaini@xxxxxxxxxxxxxxxxxxx/ > [2] https://lore.kernel.org/lkml/20220405093759.1126835-2-alex.bennee@xxxxxxxxxx/ > [3] https://lore.kernel.org/linux-mmc/1478548394-8184-2-git-send-email-tomas.winkler@xxxxxxxxx/ > [4] https://optee.readthedocs.io/en/latest/architecture/secure_storage.html#rpmb-secure-storage > [5] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c44b6be62e8dd4ee0a308c36a70620613e6fc55f > [6] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7269cba53d906cf257c139d3b3a53ad272176bca > > Thanks, > Jens > > Changes since Shyam's RFC: > * Removed the remaining leftover rpmb_cdev_*() function calls > * Refactored the struct rpmb_ops with all the previous ops replaced, in > some sense closer to [3] with the route_frames() op > * Added rpmb_route_frames() > * Added struct rpmb_frame, enum rpmb_op_result, and enum rpmb_type from [3] > * Removed all functions not needed in the OP-TEE use case > * Added "mmc: block: register RPMB partition with the RPMB subsystem", based > on the commit with the same name in [3] > * Added "optee: probe RPMB device using RPMB subsystem" for integration > with OP-TEE > * Moved the RPMB driver into drivers/misc/rpmb-core.c > * Added my name to MODULE_AUTHOR() in rpmb-core.c > * Added an rpmb_mutex to serialize access to the IDA > * Removed the target parameter from all rpmb_*() functions since it's > currently unused > Thanks for working on this. This is a huge step towards supporting TEE kernel client drivers. IIRC you mentioned offline to test it with virtio RPMB on Qemu. If it works then I would be happy to try it out as well. Along with that can you point me to the corresponding OP-TEE OS changes? I suppose as you are just adding 3 new RPC calls in patch#3, so we should be fine ABI wise although people have to uprev both OP-TEE and Linux kernel to get this feature enabled. However, OP-TEE should gate those RPCs behind a config flag or can just fallback to user-space supplicant if those aren't supported? -Sumit > > > Jens Wiklander (3): > rpmb: add Replay Protected Memory Block (RPMB) subsystem > mmc: block: register RPMB partition with the RPMB subsystem > optee: probe RPMB device using RPMB subsystem > > MAINTAINERS | 7 + > drivers/misc/Kconfig | 9 ++ > drivers/misc/Makefile | 1 + > drivers/misc/rpmb-core.c | 247 ++++++++++++++++++++++++++++++ > drivers/mmc/core/block.c | 177 +++++++++++++++++++++ > drivers/tee/optee/core.c | 1 + > drivers/tee/optee/ffa_abi.c | 2 + > drivers/tee/optee/optee_private.h | 6 + > drivers/tee/optee/optee_rpc_cmd.h | 33 ++++ > drivers/tee/optee/rpc.c | 221 ++++++++++++++++++++++++++ > drivers/tee/optee/smc_abi.c | 2 + > include/linux/rpmb.h | 184 ++++++++++++++++++++++ > 12 files changed, 890 insertions(+) > create mode 100644 drivers/misc/rpmb-core.c > create mode 100644 include/linux/rpmb.h > > > base-commit: 41bccc98fb7931d63d03f326a746ac4d429c1dd3 > -- > 2.34.1 >
