Re: [PATCH v2 5/6] tee: qcomtee: Add support for registering QTEE services on TEE bus

[Harshal Dev]

Hi Amir,

On 29-07-2026 12:35 pm, Amirreza Zarrabi wrote:
> Hi Harshal,
> 
> On 7/22/2026 4:59 PM, Harshal Dev wrote:
>> QTEE exposes certain secure services implemented either within the QTEE
>> kernel or via pre-loaded Trusted Applications (TAs). Such always-available
>> services can be readily accessed by TEE client drivers via QTEE's
>> object-IPC protocol if the service is registered as a device on the TEE
>> bus.
>>
>> One such service is the EFI-variables service, implemented by the
>> uefisecapp TA which enables kernel clients to access EFI variables at
>> runtime.
>>
>> Maintain a static list of such always-available secure services and add
>> support for the QCOMTEE driver to register these services as devices on
>> the TEE bus during probe.
>>
>> Signed-off-by: Harshal Dev <harshal.dev@xxxxxxxxxxxxxxxx>
>> ---
>>  drivers/tee/qcomtee/call.c           | 160 ++++++++++++++++++++++++++++++++++-
>>  drivers/tee/qcomtee/core.c           |   9 +-
>>  drivers/tee/qcomtee/qcomtee.h        |  12 +++
>>  drivers/tee/qcomtee/qcomtee_msg.h    |   1 +
>>  drivers/tee/qcomtee/qcomtee_object.h |   3 +-
>>  5 files changed, 177 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
>> index c1bba5fbfa3e..e909955e6b21 100644
>> --- a/drivers/tee/qcomtee/call.c
>> +++ b/drivers/tee/qcomtee/call.c
>> @@ -662,7 +662,7 @@ static void qcomtee_get_qtee_feature_list(struct tee_context *ctx, u32 id,
>>  {
>>  	struct qcomtee_object *client_env, *service;
>>  	struct qcomtee_arg u[3] = { 0 };
>> -	int result;
>> +	int result, error = 0;
>>  
>>  	struct qcomtee_object_invoke_ctx *oic __free(kfree) =
>>  		qcomtee_object_invoke_ctx_alloc(ctx, true);
>> @@ -675,9 +675,13 @@ static void qcomtee_get_qtee_feature_list(struct tee_context *ctx, u32 id,
>>  
>>  	/* Get ''FeatureVersions Service'' object. */
>>  	service = qcomtee_object_get_service(oic, client_env,
>> -					     QCOMTEE_FEATURE_VER_UID);
>> -	if (service == NULL_QCOMTEE_OBJECT)
>> +					     QCOMTEE_FEATURE_VER_UID,
>> +					     &error);
>> +	if (service == NULL_QCOMTEE_OBJECT) {
>> +		if (error)
>> +			pr_err("Failed to get service! error: %d\n", error);
>>  		goto out_failed;
>> +	}
> 
> no need to check for !error (why new variable reuse result),

Ack. will use 'result' everywhere where I am calling this. Makes sense.

> just print "FeatureVersions Service unavailable (%d)", result
> The message "Failed to get service! error: %d\n" is not helpful.

Ack.

> 
>>  
>>  	/* IB: Feature to query. */
>>  	u[0].b.addr = &id;
>> @@ -697,6 +701,153 @@ static void qcomtee_get_qtee_feature_list(struct tee_context *ctx, u32 id,
>>  	qcomtee_object_put(client_env);
>>  }
>>  
>> +/**
>> + * is_qcomtee_service_available() - Check if the QTEE service identified by the UID
>> + * is available
>> + * @ctx: TEE context.
>> + * @uid: 32-bit UID of the service.
>> + *
>> + * Returns true if the service exists and is available.
>> + * Returns false if a service is not exposed by QTEE.
>> + */
>> +static bool is_qcomtee_service_available(struct tee_context *ctx, u32 uid)
>> +{
>> +	struct qcomtee_object *client_env;
>> +	struct qcomtee_object *service;
>> +	int error = 0;
>> +	bool ret = false;
>> +
>> +	struct qcomtee_object_invoke_ctx *oic __free(kfree) =
>> +		qcomtee_object_invoke_ctx_alloc(ctx, true);
>> +	if (!oic)
>> +		return ret;
>> +
>> +	client_env = qcomtee_object_get_client_env(oic);
>> +	if (client_env == NULL_QCOMTEE_OBJECT)
>> +		return ret;
>> +
>> +	/* Get service object corresponding to the uid. */
>> +	service = qcomtee_object_get_service(oic, client_env, uid, &error);
>> +	if (service != NULL_QCOMTEE_OBJECT) {
>> +		qcomtee_object_put(service);
>> +		ret = true;
>> +	}
>> +
>> +	/* When we fail to get the service, QTEE provides the reason. */
>> +	if (error)
>> +		pr_err("Failed to get service! error: %d\n", error);
>> +
> 
> This is not a useful message. We need to know which static service is missing:
> e.g. print "%s is unavailable (%d)", qcom.tz.uefisecapp, error.

Ack.

> Also it is possible to re-org to avoid qcomtee_object_invoke_ctx_alloc() and
> qcomtee_object_get_client_env() on each iteration? oic is reusable.
>

Agreed, since this is called in a loop, it results in unnecessary re-allocation
on every iteration and call to QTEE for getting client_env().
Ack. 
>> +	qcomtee_object_put(client_env);
>> +	return ret;
>> +}
>> +
>> +/*
>> + * QTEE Service UUID name space identifier
>> + *
>> + * A random UUID that is allocated as a name space identifier for forming UUID's
>> + * representing secure services exposed by QTEE.
>> + */
>> +static const uuid_t qtee_service_uuid_ns = UUID_INIT(0xe1b48857, 0x6154, 0x49f9,
>> +						     0x93, 0x4e, 0xa2, 0xf2,
>> +						     0x0a, 0xba, 0x98, 0x42);
>> +
>> +static const struct qtee_service qtee_services[] = {
>> +	{ "qcom.tz.uefisecapp",
>> +	   QCOMTEE_UEFI_SEC_UID }
>> +};
>> +
>> +static void qtee_release_service(struct device *dev)
>> +{
>> +	struct tee_client_device *qtee_service = to_tee_client_device(dev);
>> +
>> +	kfree(qtee_service);
>> +}
>> +
>> +/**
>> + * qtee_enumerate_service() - Enumerate a given QTEE service and register
>> + * it on the TEE bus as a TEE client device
>> + * @ctx: TEE context.
>> + * @service_uuid: UUID of the service to be registered on the TEE bus.
>> + * @uid: 32-bit UID used by QTEE to identify the service.
>> + *
>> + * Returns 0 on success and < 0 on failure.
>> + */
>> +static int qtee_enumerate_service(struct tee_context *ctx, const char *service_name,
>> +				  const u32 uid)
>> +{
>> +	struct tee_client_device *qtee_service;
>> +	uuid_t service_uuid;
>> +	int rc;
>> +
>> +	if (!is_qcomtee_service_available(ctx, uid))
>> +		return -ENXIO;
> 
> -EOPNOTSUPP?

Ack.

> 
>> +
>> +	tee_generate_uuid_v5(&service_uuid, &qtee_service_uuid_ns, service_name,
>> +			     strlen(service_name));
>> +
>> +	qtee_service = kzalloc_obj(*qtee_service);
>> +	if (!qtee_service)
>> +		return -ENOMEM;
>> +
>> +	qtee_service->dev.bus = &tee_bus_type;
>> +	qtee_service->dev.release = qtee_release_service;
>> +	if (dev_set_name(&qtee_service->dev, "qtee-svc-%pUb", &service_uuid)) {
>> +		kfree(qtee_service);
>> +		return -ENOMEM;
>> +	}
>> +	uuid_copy(&qtee_service->id.uuid, &service_uuid);
>> +
>> +	rc = device_register(&qtee_service->dev);
>> +	if (rc) {
>> +		pr_err("QTEE service registration failed, err: %d\n", rc);
>> +		put_device(&qtee_service->dev);
>> +		kfree(qtee_service);
> 
> It is double free!? is not put_device enough?
>

Thank you for catching this, I did not realize that put_device frees the entire
struct.

Ack. 
>> +		return rc;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * qtee_enumerate_services() - Enumerate all the secure services exposed by QTEE
>> + * from the static 'qtee_services' list and register them on the TEE bus as
>> + * TEE client devices.
>> + *
>> + * Not all versions of QTEE support a given service. Hence, we try to
>> + * enumerate as many services from the 'qtee_services' list as possible.
>> + * Not being able to enumerate a service shouldn't cause the driver probe
>> + * to fail since none of the services in the list are mandatory for
>> + * establishing communication with QTEE.
>> + * @ctx: TEE context.
>> + */
>> +static void qtee_enumerate_services(struct tee_context *ctx)
>> +{
>> +	int rc;
>> +	u32 idx;
>> +
>> +	for (idx = 0; idx < ARRAY_SIZE(qtee_services); idx++) {
>> +		rc = qtee_enumerate_service(ctx, qtee_services[idx].name,
>> +					    qtee_services[idx].uid);
>> +		if (rc == -ENXIO)
>> +			pr_err("QTEE does not implement service %d.\n",
>> +			       qtee_services[idx].uid);
> 
> If you print in is_qcomtee_service_available(), why here again?
>

Ack, will remove from here.

Regards,
Harshal 
> - Amir
> 
>> +	}
>> +}
>> +
>> +static int qtee_unregister_service(struct device *dev, void *data)
>> +{
>> +	if (!strncmp(dev_name(dev), "qtee-svc", strlen("qtee-svc")))
>> +		device_unregister(dev);
>> +
>> +	return 0;
>> +}
>> +
>> +static void qtee_unregister_services(void)
>> +{
>> +	bus_for_each_dev(&tee_bus_type, NULL, NULL,
>> +			 qtee_unregister_service);
>> +}
>> +
>>  static const struct tee_driver_ops qcomtee_ops = {
>>  	.get_version = qcomtee_get_version,
>>  	.open = qcomtee_open,
>> @@ -778,6 +929,8 @@ static int qcomtee_probe(struct platform_device *pdev)
>>  		QTEE_VERSION_GET_MINOR(qcomtee->qtee_version),
>>  		QTEE_VERSION_GET_PATCH(qcomtee->qtee_version));
>>  
>> +	qtee_enumerate_services(qcomtee->ctx);
>> +
>>  	return 0;
>>  
>>  err_dest_wq:
>> @@ -807,6 +960,7 @@ static void qcomtee_remove(struct platform_device *pdev)
>>  {
>>  	struct qcomtee *qcomtee = platform_get_drvdata(pdev);
>>  
>> +	qtee_unregister_services();
>>  	teedev_close_context(qcomtee->ctx);
>>  	/* Wait for RELEASE operations to be processed for QTEE objects. */
>>  	tee_device_unregister(qcomtee->teedev);
>> diff --git a/drivers/tee/qcomtee/core.c b/drivers/tee/qcomtee/core.c
>> index b1cb50e434f0..4e39e867c3e9 100644
>> --- a/drivers/tee/qcomtee/core.c
>> +++ b/drivers/tee/qcomtee/core.c
>> @@ -896,19 +896,20 @@ qcomtee_object_get_client_env(struct qcomtee_object_invoke_ctx *oic)
>>  
>>  struct qcomtee_object *
>>  qcomtee_object_get_service(struct qcomtee_object_invoke_ctx *oic,
>> -			   struct qcomtee_object *client_env, u32 uid)
>> +			   struct qcomtee_object *client_env, u32 uid,
>> +			   int *result)
>>  {
>>  	struct qcomtee_arg u[3] = { 0 };
>> -	int ret, result;
>> +	int ret;
>>  
>>  	u[0].b.addr = &uid;
>>  	u[0].b.size = sizeof(uid);
>>  	u[0].type = QCOMTEE_ARG_TYPE_IB;
>>  	u[1].type = QCOMTEE_ARG_TYPE_OO;
>>  	ret = qcomtee_object_do_invoke(oic, client_env, QCOMTEE_CLIENT_ENV_OPEN,
>> -				       u, &result);
>> +				       u, result);
>>  
>> -	if (ret || result)
>> +	if (ret || *result)
>>  		return NULL_QCOMTEE_OBJECT;
>>  
>>  	return u[1].o;
>> diff --git a/drivers/tee/qcomtee/qcomtee.h b/drivers/tee/qcomtee/qcomtee.h
>> index f39bf63fd1c2..66d305a46c0a 100644
>> --- a/drivers/tee/qcomtee/qcomtee.h
>> +++ b/drivers/tee/qcomtee/qcomtee.h
>> @@ -17,6 +17,8 @@
>>  #define QCOMTEE_OBJREF_FLAG_USER	BIT(1)
>>  #define QCOMTEE_OBJREF_FLAG_MEM		BIT(2)
>>  
>> +#define QTEE_UUID_NS_NAME_SIZE	        128
>> +
>>  /**
>>   * struct qcomtee - Main service struct.
>>   * @teedev: client device.
>> @@ -39,6 +41,16 @@ struct qcomtee {
>>  	u32 qtee_version;
>>  };
>>  
>> +/**
>> + * struct qtee_service - A secure service exposed by QTEE identified by a 32-bit UID.
>> + * @name: Name of the QTEE service.
>> + * @uid: 32-bit UID used by QTEE to identify the service.
>> + */
>> +struct qtee_service {
>> +	const char *name;
>> +	const u32 uid;
>> +};
>> +
>>  void qcomtee_fetch_async_reqs(struct qcomtee_object_invoke_ctx *oic);
>>  struct qcomtee_object *qcomtee_idx_erase(struct qcomtee_object_invoke_ctx *oic,
>>  					 u32 idx);
>> diff --git a/drivers/tee/qcomtee/qcomtee_msg.h b/drivers/tee/qcomtee/qcomtee_msg.h
>> index 878f70178a5b..ecaf8db67d45 100644
>> --- a/drivers/tee/qcomtee/qcomtee_msg.h
>> +++ b/drivers/tee/qcomtee/qcomtee_msg.h
>> @@ -105,6 +105,7 @@ union qcomtee_msg_arg {
>>  #define QTEE_VERSION_GET_MINOR(x) (((x) >> 12) & 0xffU)
>>  #define QTEE_VERSION_GET_PATCH(x) ((x) >> 0 & 0xfffU)
>>  
>> +#define QCOMTEE_UEFI_SEC_UID            413
>>  /* Response types as returned from qcomtee_object_invoke_ctx_invoke(). */
>>  
>>  /* The message contains a callback request. */
>> diff --git a/drivers/tee/qcomtee/qcomtee_object.h b/drivers/tee/qcomtee/qcomtee_object.h
>> index 7bd6e23b038c..f4cb9b8fcbd4 100644
>> --- a/drivers/tee/qcomtee/qcomtee_object.h
>> +++ b/drivers/tee/qcomtee/qcomtee_object.h
>> @@ -316,6 +316,7 @@ qcomtee_object_get_client_env(struct qcomtee_object_invoke_ctx *oic);
>>  
>>  struct qcomtee_object *
>>  qcomtee_object_get_service(struct qcomtee_object_invoke_ctx *oic,
>> -			   struct qcomtee_object *client_env, u32 uid);
>> +			   struct qcomtee_object *client_env, u32 uid,
>> +			   int *result);
>>  
>>  #endif /* QCOMTEE_OBJECT_H */
>>
>