[PATCH RFC v2 3/8] tee: optee: add RPMI shared-memory and parameter support
Amirreza Zarrabi
amirreza.zarrabi at oss.qualcomm.com
Thu Oct 8 15:27:26 PDT 2026
Hi Jens,
On 10/8/2026 6:10 PM, Jens Wiklander wrote:
> Hi Amir,
>
> On Tue, Oct 6, 2026 at 2:40 AM Amirreza Zarrabi
> <amirreza.zarrabi at oss.qualcomm.com> wrote:
>>
>> OP-TEE commands and RPCs need shared memory that secure world can
>> identify through RPMI parcels.
>>
>> Register normal-world pages as read-write parcels shared with the
>> OP-TEE endpoint. Track each parcel ID and nonce in a hash table and
>> store the combined identity in tee_shm.sec_world_id. Use a fixed
>> nonzero nonce to distinguish registered memory from NULL references.
>>
>> Add conversions between TEE parameters and parcel memory references.
>>
>> On client memory unregistration, ask OP-TEE to release its mapping
>> before reclaiming the parcel. Supplicant memory has already been
>> released by OP-TEE through its SHM_FREE RPC and only needs reclaiming.
>>
>> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi at oss.qualcomm.com>
>> ---
>> drivers/tee/optee/Makefile | 1 +
>> drivers/tee/optee/optee_private.h | 27 +++
>> drivers/tee/optee/rpmi_abi.c | 417 ++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 445 insertions(+)
>>
>> diff --git a/drivers/tee/optee/Makefile b/drivers/tee/optee/Makefile
>> index 183cdde1ac04..8576cc73a922 100644
>> --- a/drivers/tee/optee/Makefile
>> +++ b/drivers/tee/optee/Makefile
>> @@ -9,6 +9,7 @@ optee-objs += supp.o
>> optee-objs += device.o
>> optee-$(CONFIG_HAVE_ARM_SMCCC) += smc_abi.o
>> optee-$(CONFIG_ARM_FFA_TRANSPORT) += ffa_abi.o
>> +optee-$(CONFIG_RISCV_RPMI_TEE_TRANSPORT) += rpmi_abi.o
>>
>> # for tracing framework to find optee_trace.h
>> CFLAGS_smc_abi.o := -I$(src)
>> diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
>> index 02d6f79df407..2422caf3c883 100644
>> --- a/drivers/tee/optee/optee_private.h
>> +++ b/drivers/tee/optee/optee_private.h
>> @@ -180,6 +180,28 @@ struct optee_ffa {
>> };
>> #endif
>>
>> +#if IS_REACHABLE(CONFIG_RISCV_RPMI_TEE_TRANSPORT)
>> +struct rpmi_tee_device;
>> +
>> +/**
>> + * struct optee_rpmi - RPMI shared-memory identity state
>> + * @rdev: owning RPMI service device
>> + * @shm_rht_lock: protects parcel lookup, insertion, removal and publication
>> + * @shm_rht: lookup by the host-endian parcel ID and nonce pair
>> + *
>> + * Callers keep their tee_shm alive while using its registration. Lookup
>> + * returns a raw pointer; the mutex does not protect its lifetime after
>> + * unlocking. Never hold @shm_rht_lock across a transport operation, RPC or
>> + * thread-availability wait.
>> + */
>> +struct optee_rpmi {
>> + struct rpmi_tee_device *rdev;
>> + /* Protects parcel lookup, insertion, removal and publication. */
>> + struct mutex shm_rht_lock;
>> + struct rhashtable shm_rht;
>> +};
>> +#endif
>> +
>> struct optee;
>>
>> /**
>> @@ -240,6 +262,7 @@ struct optee_ops {
>> * @ctx: driver internal TEE context
>> * @smc: specific to SMC ABI
>> * @ffa: specific to FF-A ABI
>> + * @rpmi: specific to RPMI ABI
>> * @shm_arg_cache: shared memory cache argument
>> * @call_queue: queue of threads waiting to call @invoke_fn
>> * @notif: notification synchronization struct
>> @@ -271,6 +294,9 @@ struct optee {
>> #endif
>> #if IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)
>> struct optee_ffa ffa;
>> +#endif
>> +#if IS_REACHABLE(CONFIG_RISCV_RPMI_TEE_TRANSPORT)
>> + struct optee_rpmi rpmi;
>> #endif
>> };
>> struct optee_shm_arg_cache shm_arg_cache;
>> @@ -464,4 +490,5 @@ static inline void optee_ffa_abi_unregister(void)
>> }
>> #endif
>>
>> +
>> #endif /*OPTEE_PRIVATE_H*/
>> diff --git a/drivers/tee/optee/rpmi_abi.c b/drivers/tee/optee/rpmi_abi.c
>> new file mode 100644
>> index 000000000000..e7fc853cfb15
>> --- /dev/null
>> +++ b/drivers/tee/optee/rpmi_abi.c
>> @@ -0,0 +1,417 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
>> + */
>> +
>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> +
>> +#include <linux/cleanup.h>
>> +#include <linux/mailbox/riscv-rpmi-message.h>
>> +#include <linux/overflow.h>
>> +#include <linux/rpmi_tee.h>
>> +#include <linux/slab.h>
>> +#include <linux/unaligned.h>
>> +#include "optee_private.h"
>> +#include "optee_rpmi.h"
>> +
>> +/* Nonzero nonce keeps parcel ID zero distinct from a null reference. */
>> +#define OPTEE_RPMI_SHM_NONCE 1
> The spec describes this as:
>
> A token nonce which receivers will need to present to the framework,
> together with MEM_PARCEL_ID, to accept the memory.
> It is intended as a way to reduce the likelihood of accidental
> collisions on MEM_PARCEL_ID values, which can be reused by the
> framework after they have been destroyed.
>
> Why don't we change the nonce with each new parcel to live up to that?
>
True, That's the intention. I just set it to a constsnt to reduce the
code size so we can concentrate on the ABI. I'll include the nonce
allocation in the next version.
>> +
>> +struct optee_rpmi_parcel_key {
>> + u32 parcel_id;
>> + u32 nonce;
>> +};
>> +
>> +struct optee_rpmi_shm_rht_entry {
>> + struct rhash_head node;
>> + struct optee_rpmi_parcel_key key;
>> + struct tee_shm *shm;
>> +};
>> +
>> +static const struct rhashtable_params optee_rpmi_shm_rht_params = {
>> + .head_offset = offsetof(struct optee_rpmi_shm_rht_entry, node),
>> + .key_offset = offsetof(struct optee_rpmi_shm_rht_entry, key),
>> + .key_len = sizeof(struct optee_rpmi_parcel_key),
>> + .automatic_shrinking = true,
>> +};
>> +
>> +/* Keep transport errors separate from the control status in a response. */
>> +static int optee_rpmi_call_with_status(struct optee *optee,
>> + const void *req, size_t req_len,
>> + void *resp, size_t resp_size,
>> + s32 *status)
>> +{
>> + struct rpmi_tee_device *rdev = optee->rpmi.rdev;
>> + size_t received = resp_size;
>> + int ret;
>> +
>> + ret = rdev->ops->msg_ops->call(rdev, req, req_len, resp, &received);
>> + if (ret)
>> + return ret;
>> +
>> + if (received != resp_size)
>> + return -EPROTO;
>> +
>> + *status = get_unaligned_le32(resp);
>> +
>> + return 0;
>> +}
>> +
>> +/**
>> + * optee_rpmi_call - Send a control request and decode its RPMI status
>> + * @optee: OP-TEE instance.
>> + * @req: Control request, including the operation number.
>> + * @req_len: Request size in bytes.
>> + * @resp: Response buffer, beginning with a little-endian RPMI status.
>> + * @resp_size: Exact expected response size, including the status field.
>> + *
>> + * Return: 0 on success, a transport error, -EPROTO for an unexpected response
>> + * size, or the control status converted to a Linux error code.
>> + */
>> +static int optee_rpmi_call(struct optee *optee, const void *req, size_t req_len,
>> + void *resp, size_t resp_size)
>> +{
>> + s32 status;
>> + int ret;
>> +
>> + ret = optee_rpmi_call_with_status(optee, req, req_len, resp, resp_size,
>> + &status);
>> + if (ret)
>> + return ret;
>> +
>> + return rpmi_to_linux_error(status);
>> +}
>> +
>> +static int optee_rpmi_shm_rht_init(struct optee *optee)
>> +{
>> + int ret;
>> +
>> + mutex_init(&optee->rpmi.shm_rht_lock);
>> + ret = rhashtable_init(&optee->rpmi.shm_rht, &optee_rpmi_shm_rht_params);
>> + if (ret)
>> + mutex_destroy(&optee->rpmi.shm_rht_lock);
>> +
>> + return ret;
>> +}
>> +
>> +static void optee_rpmi_shm_rht_free(void *ptr, void *arg)
>> +{
>> + kfree(ptr);
>> +}
>> +
>> +static void optee_rpmi_shm_rht_uninit(struct optee *optee)
>> +{
>> + rhashtable_free_and_destroy(&optee->rpmi.shm_rht,
>> + optee_rpmi_shm_rht_free, NULL);
>> + mutex_destroy(&optee->rpmi.shm_rht_lock);
>> +}
>> +
>> +/* Allocate and publish a parcel-to-SHM mapping. */
>> +static int optee_rpmi_shm_rht_add(struct optee *optee, struct tee_shm *shm,
>> + u32 parcel_id, u32 nonce)
>> +{
>> + struct optee_rpmi_shm_rht_entry *entry;
>> + int ret;
>> +
>> + entry = kzalloc_obj(*entry);
>> + if (!entry)
>> + return -ENOMEM;
>> +
>> + entry->shm = shm;
>> + entry->key.parcel_id = parcel_id;
>> + entry->key.nonce = nonce;
>> +
>> + scoped_guard(mutex, &optee->rpmi.shm_rht_lock)
>> + ret = rhashtable_lookup_insert_fast(&optee->rpmi.shm_rht,
>> + &entry->node,
>> + optee_rpmi_shm_rht_params);
>> + if (ret)
>> + kfree(entry);
>> +
>> + return ret;
>> +}
>> +
>> +/* Remove and free a parcel-to-SHM mapping. */
>> +static int optee_rpmi_shm_rht_rm(struct optee *optee, u32 parcel_id, u32 nonce)
>> +{
>> + struct optee_rpmi_shm_rht_entry *entry;
>> + struct optee_rpmi_parcel_key key = {
>> + .parcel_id = parcel_id,
>> + .nonce = nonce,
>> + };
>> + int ret = -ENOENT;
>> +
>> + scoped_guard(mutex, &optee->rpmi.shm_rht_lock) {
>> + entry = rhashtable_lookup_fast(&optee->rpmi.shm_rht, &key,
>> + optee_rpmi_shm_rht_params);
>> + if (entry)
>> + ret = rhashtable_remove_fast(&optee->rpmi.shm_rht,
>> + &entry->node,
>> + optee_rpmi_shm_rht_params);
>> + }
>> +
>> + if (!ret)
>> + kfree(entry);
>> +
>> + return ret;
>> +}
>> +
>> +/* Return a raw pointer; the surrounding call or RPC owns the SHM lifetime. */
>> +static struct tee_shm *
>> +optee_rpmi_get_shm_for_parcel(struct optee *optee, u32 parcel_id, u32 nonce)
>> +{
>> + struct optee_rpmi_shm_rht_entry *entry;
>> + struct optee_rpmi_parcel_key key = {
>> + .parcel_id = parcel_id,
>> + .nonce = nonce,
>> + };
>> +
>> + guard(mutex)(&optee->rpmi.shm_rht_lock);
>> + entry = rhashtable_lookup_fast(&optee->rpmi.shm_rht, &key,
>> + optee_rpmi_shm_rht_params);
>> +
>> + return entry ? entry->shm : NULL;
>
> Please use a full if statement instead of the ternary operator
>
Ack.
>> +}
>> +
>> +/* Extract the parcel ID and nonce stored in the SHM identity. */
>> +static void optee_rpmi_shm_get_identity(const struct tee_shm *shm,
>> + u32 *parcel_id, u32 *nonce)
>> +{
>> + *parcel_id = lower_32_bits(shm->sec_world_id);
>> + *nonce = upper_32_bits(shm->sec_world_id);
>
> By keeping parcel_id and nonce in separate fields, we add quite a bit
> of code only to handle u64 -> u32 + u32 and vice versa. I wonder if it
> wouldn't be easier always to keep them in a u64 and say that the upper
> 32 bits are a nonce, or something. With that, we could make the
> optee_shm_rem_ffa_handle() function and friends common helpers in the
> optee driver.
Yes. I'll do that.
I'll also try to extract the sharable functions from FFA in the next version.
>
>> +}
>> +
>> +static int optee_rpmi_shm_register(struct tee_context *ctx, struct tee_shm *shm,
>> + struct page **pages, size_t num_pages,
>> + unsigned long start)
>> +{
>> + struct optee *optee = tee_get_drvdata(ctx->teedev);
>> + struct rpmi_tee_device *rdev = optee->rpmi.rdev;
>> + struct rpmi_tee_mem_receiver receiver = {
>> + .endpoint_id = rdev->endpoint_id,
>> + .access = RPMI_TEE_MEM_ACCESS_READ | RPMI_TEE_MEM_ACCESS_WRITE,
>> + };
>> + struct rpmi_tee_mem_args args = {
>> + .nonce = OPTEE_RPMI_SHM_NONCE,
>> + .receivers = &receiver,
>> + .receiver_count = 1,
>> + .creator_access = RPMI_TEE_MEM_ACCESS_READ |
>> + RPMI_TEE_MEM_ACCESS_WRITE,
>> + };
>> + struct sg_table sgt;
>> + int ret;
>> +
>> + ret = optee_check_mem_type(start, num_pages);
>> + if (ret)
>> + return ret;
>> +
>> + ret = sg_alloc_table_from_pages(&sgt, pages, num_pages, 0,
>> + num_pages * PAGE_SIZE, GFP_KERNEL);
>> + if (ret)
>> + return ret;
>> +
>> + args.sg = sgt.sgl;
>> + ret = rdev->ops->mem_ops->memory_share(rdev, &args);
>> + sg_free_table(&sgt);
>> + if (ret)
>> + return ret;
>> +
>> + ret = optee_rpmi_shm_rht_add(optee, shm, args.parcel_id, args.nonce);
>> + if (ret) {
>> + int reclaim_ret;
>> +
>> + reclaim_ret = rdev->ops->mem_ops->memory_reclaim(rdev, args.parcel_id);
>> + if (reclaim_ret)
>> + dev_err(&rdev->dev, "reclaim parcel %#x failed: %d\n",
>> + args.parcel_id, reclaim_ret);
>> + return ret;
>> + }
>> +
>> + shm->sec_world_id = ((u64)args.nonce << 32) | args.parcel_id;
>> +
>> + return 0;
>> +}
>> +
>> +static int optee_rpmi_shm_unregister(struct tee_context *ctx,
>> + struct tee_shm *shm)
>> +{
>> + struct optee *optee = tee_get_drvdata(ctx->teedev);
>> + struct rpmi_tee_device *rdev = optee->rpmi.rdev;
>> + struct optee_rpmi_unregister_req req;
>> + struct optee_rpmi_status_resp resp;
>> + u32 parcel_id, nonce;
>> + int ret;
>> +
>> + optee_rpmi_shm_get_identity(shm, &parcel_id, &nonce);
>> + optee_rpmi_shm_rht_rm(optee, parcel_id, nonce);
>> + shm->sec_world_id = 0;
>> +
>> + req.op = cpu_to_le32(OPTEE_RPMI_UNREGISTER_SHM);
>> + req.parcel_id = cpu_to_le32(parcel_id);
>> + req.nonce = cpu_to_le32(nonce);
>> + ret = optee_rpmi_call(optee, &req, sizeof(req), &resp, sizeof(resp));
>> + if (ret)
>> + dev_err(&rdev->dev, "unregister parcel %#x failed: %d\n",
>> + parcel_id, ret);
>> +
>> + ret = rdev->ops->mem_ops->memory_reclaim(rdev, parcel_id);
>> + if (ret)
>> + dev_err(&rdev->dev, "reclaim parcel %#x failed: %d\n",
>> + parcel_id, ret);
>> +
>> + return ret;
>> +}
>> +
>> +static int optee_rpmi_shm_unregister_supp(struct tee_context *ctx,
>> + struct tee_shm *shm)
>> +{
>> + struct optee *optee = tee_get_drvdata(ctx->teedev);
>> + struct rpmi_tee_device *rdev = optee->rpmi.rdev;
>> + u32 parcel_id, nonce;
>> + int ret;
>> +
>> + optee_rpmi_shm_get_identity(shm, &parcel_id, &nonce);
>> + optee_rpmi_shm_rht_rm(optee, parcel_id, nonce);
>> + shm->sec_world_id = 0;
>> + /* OP-TEE has already retired the parcel through SHM_FREE RPC. */
>> + ret = rdev->ops->mem_ops->memory_reclaim(rdev, parcel_id);
>> + if (ret)
>> + dev_err(&rdev->dev, "reclaim parcel %#x failed: %d\n",
>> + parcel_id, ret);
>> +
>> + return ret;
>> +}
>> +
>> +/* Convert a memory reference to an OP-TEE RPMI parcel reference. */
>> +static int to_msg_param_rpmi_mem(struct optee_msg_param *mp,
>> + const struct tee_param *p)
>> +{
>> + struct tee_shm *shm = p->u.memref.shm;
>> +
>> + mp->attr = OPTEE_MSG_ATTR_TYPE_PMEM_INPUT + p->attr -
>> + TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
>> + memset(&mp->u, 0, sizeof(mp->u));
>> + /* For !shm, return parcel_id = 0 and nonce = 0 to represent NULL. */
>> + if (shm) {
>> + if (check_add_overflow((u64)shm->offset,
>> + (u64)p->u.memref.shm_offs,
>> + &mp->u.pmem.offs))
>> + return -EINVAL;
>
> By combining the shm->offset with p->u.memref.shm_offs, OP-TEE
> requires an explicit call to register the shared memory so it knows
> the initial page offset. Compared with the FF-A ABI, which can tell
> the initial page offset from mp->u.fmem.internal_offs. See also the
> mobj_ffa_get_by_cookie() call in set_fmem_param() in
> core/tee/entry_std.c in optee_os.git
>
I addressed this in my reply to the earlier commit. The intended
secure-side memory object covers the entire parcel, so the supplied
offset is parcel-relative. OP-TEE can retrieve the parcel lazily and
apply that offset directly, without a separate SHM registration call.
Is there a requirement for OP-TEE to know the initial page offset
separately that I am overlooking? I understand it helps with a
logical buffer representation and to match with Linux SHM.
The whole-parcel memory-object model appears to work without it.
But if you feel, having seperate offsets is better or may help
for some unification with FFA in future. I can do that :).
>> +
>> + optee_rpmi_shm_get_identity(shm, &mp->u.pmem.parcel_id,
>> + &mp->u.pmem.nonce);
>> + }
>> +
>> + mp->u.pmem.size = p->u.memref.size;
>> +
>> + return 0;
>> +}
>> +
>> +static int optee_rpmi_to_msg_param(struct optee *optee,
>> + struct optee_msg_param *msg_params,
>> + size_t num_params,
>> + const struct tee_param *params)
>> +{
>> + size_t n;
>> +
>> + for (n = 0; n < num_params; n++) {
>> + const struct tee_param *p = params + n;
>> + struct optee_msg_param *mp = msg_params + n;
>
> Please add an empty line after the variables.
>
Ack.
Thanks Jens for the review.
Best Regards,
Amir
> Cheers,
> Jens
>
>> + switch (p->attr) {
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
>> + mp->attr = OPTEE_MSG_ATTR_TYPE_NONE;
>> + memset(&mp->u, 0, sizeof(mp->u));
>> + break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
>> + optee_to_msg_param_value(mp, p);
>> + break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>> + if (to_msg_param_rpmi_mem(mp, p))
>> + return -EINVAL;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/* Convert an RPMI parcel reference to a memref; callers own SHM lifetime. */
>> +static int from_msg_param_rpmi_mem(struct optee *optee, struct tee_param *p,
>> + u32 attr, const struct optee_msg_param *mp)
>> +{
>> + struct tee_shm *shm;
>> + u64 offset;
>> +
>> + p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT + attr -
>> + OPTEE_MSG_ATTR_TYPE_PMEM_INPUT;
>> +
>> + if (mp->u.pmem.size > SIZE_MAX)
>> + return -EOVERFLOW;
>> + p->u.memref.size = mp->u.pmem.size;
>> +
>> + if (!mp->u.pmem.nonce) {
>> + /* Return NULL shm. */
>> + if (mp->u.pmem.offs || mp->u.pmem.parcel_id)
>> + return -EINVAL;
>> + p->u.memref.shm = NULL;
>> + p->u.memref.shm_offs = 0;
>> + return 0;
>> + }
>> +
>> + shm = optee_rpmi_get_shm_for_parcel(optee, mp->u.pmem.parcel_id,
>> + mp->u.pmem.nonce);
>> + if (!shm || mp->u.pmem.offs < shm->offset)
>> + return -EINVAL;
>> +
>> + offset = mp->u.pmem.offs - shm->offset;
>> + if (offset > SIZE_MAX)
>> + return -EOVERFLOW;
>> +
>> + p->u.memref.shm = shm;
>> + p->u.memref.shm_offs = offset;
>> +
>> + return 0;
>> +}
>> +
>> +static int optee_rpmi_from_msg_param(struct optee *optee,
>> + struct tee_param *params,
>> + size_t num_params,
>> + const struct optee_msg_param *msg_params)
>> +{
>> + size_t n;
>> +
>> + for (n = 0; n < num_params; n++) {
>> + const struct optee_msg_param *mp = msg_params + n;
>> + struct tee_param *p = params + n;
>> + u32 attr = mp->attr & OPTEE_MSG_ATTR_TYPE_MASK;
>> + int ret;
>> +
>> + switch (attr) {
>> + case OPTEE_MSG_ATTR_TYPE_NONE:
>> + p->attr = TEE_IOCTL_PARAM_ATTR_TYPE_NONE;
>> + memset(&p->u, 0, sizeof(p->u));
>> + break;
>> + case OPTEE_MSG_ATTR_TYPE_VALUE_INPUT:
>> + case OPTEE_MSG_ATTR_TYPE_VALUE_OUTPUT:
>> + case OPTEE_MSG_ATTR_TYPE_VALUE_INOUT:
>> + optee_from_msg_param_value(p, attr, mp);
>> + break;
>> + case OPTEE_MSG_ATTR_TYPE_PMEM_INPUT:
>> + case OPTEE_MSG_ATTR_TYPE_PMEM_OUTPUT:
>> + case OPTEE_MSG_ATTR_TYPE_PMEM_INOUT:
>> + ret = from_msg_param_rpmi_mem(optee, p, attr, mp);
>> + if (ret)
>> + return ret;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> + }
>> + return 0;
>> +}
>>
>> --
>> 2.34.1
>>
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