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Message-ID: <8f9a7ca7-5098-40c6-94b2-490a857d7dae@oss.qualcomm.com>
Date: Thu, 12 Jun 2025 09:45:10 +1000
From: Amirreza Zarrabi <amirreza.zarrabi@....qualcomm.com>
To: Andrew Davis <afd@...com>, Jens Wiklander <jens.wiklander@...aro.org>,
Sumit Garg <sumit.garg@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konradybcio@...nel.org>,
Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
Apurupa Pattapu <quic_apurupa@...cinc.com>,
Kees Cook <kees@...nel.org>,
"Gustavo A. R. Silva" <gustavoars@...nel.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
Christian König <christian.koenig@....com>
Cc: Harshal Dev <quic_hdev@...cinc.com>, linux-arm-msm@...r.kernel.org,
op-tee@...ts.trustedfirmware.org, linux-kernel@...r.kernel.org,
linux-hardening@...r.kernel.org, dri-devel@...ts.freedesktop.org,
linaro-mm-sig@...ts.linaro.org, linux-doc@...r.kernel.org,
Sumit Garg <sumit.garg@....qualcomm.com>,
Neil Armstrong <neil.armstrong@...aro.org>
Subject: Re: [PATCH v5 03/12] tee: add TEE_IOCTL_PARAM_ATTR_TYPE_UBUF
Hi Andrew,
On 6/12/2025 8:40 AM, Andrew Davis wrote:
> On 5/27/25 1:56 AM, Amirreza Zarrabi wrote:
>> For drivers that can transfer data to the TEE without using shared
>> memory from client, it is necessary to receive the user address
>> directly, bypassing any processing by the TEE subsystem. Introduce
>> TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT/OUTPUT/INOUT to represent
>> userspace buffers.
>>
>
> Could you expand on this, what is the issue with normal MEMREF?
>
QTEE supports two types of data passing: (1) memory objects and (2) buffers.
A memory object can be a normal shared memory (shm) instance. However, a
buffer is an [offset, size] pair referring to the transport memory shared
with QTEE (established at the begining of the invocation).
There is no direct representation of VALUE in the QTEE ABI, so even basic
data types, such as int, must be passed as a buffer [offset, sizeof(int)].
VALUE cannot be used because it only represents a u64 data size. While MEMREF
is an option, it requires additional ioctl calls and memory copies.
For example, if you need to send three integers to QTEE, you would require:
(1) Three ioctl calls to allocate three shared memory pages.
(2) Three memcpy operations to copy each integer into its respective shared memory.
(3) Three memcpy operations to transfer data from shared memory to the
transport buffer shared with QTEE.
You can optimize this slightly by making a single ioctl call for shared
memory allocation. However, the backend still needs to inspect the shared
memory, parse it, and extract the data and size information.
With UBUF user pass user address and size, and ther is only one copy_from_use
in the backend.
Regards,
Amir
> Andrew
>
>> Reviewed-by: Sumit Garg <sumit.garg@....qualcomm.com>
>> Tested-by: Neil Armstrong <neil.armstrong@...aro.org>
>> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@....qualcomm.com>
>> ---
>> drivers/tee/tee_core.c | 33 +++++++++++++++++++++++++++++++++
>> include/linux/tee_drv.h | 6 ++++++
>> include/uapi/linux/tee.h | 22 ++++++++++++++++------
>> 3 files changed, 55 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
>> index b9ea5a85278c..74e40ed83fa7 100644
>> --- a/drivers/tee/tee_core.c
>> +++ b/drivers/tee/tee_core.c
>> @@ -387,6 +387,17 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params,
>> params[n].u.value.b = ip.b;
>> params[n].u.value.c = ip.c;
>> break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> + params[n].u.ubuf.uaddr = u64_to_user_ptr(ip.a);
>> + params[n].u.ubuf.size = ip.b;
>> +
>> + if (!access_ok(params[n].u.ubuf.uaddr,
>> + params[n].u.ubuf.size))
>> + return -EFAULT;
>> +
>> + 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:
>> @@ -455,6 +466,11 @@ static int params_to_user(struct tee_ioctl_param __user *uparams,
>> put_user(p->u.value.c, &up->c))
>> return -EFAULT;
>> break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> + if (put_user((u64)p->u.ubuf.size, &up->b))
>> + return -EFAULT;
>> + break;
>> case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>> case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>> if (put_user((u64)p->u.memref.size, &up->b))
>> @@ -655,6 +671,13 @@ static int params_to_supp(struct tee_context *ctx,
>> ip.b = p->u.value.b;
>> ip.c = p->u.value.c;
>> break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> + ip.a = (u64)p->u.ubuf.uaddr;
>> + ip.b = p->u.ubuf.size;
>> + ip.c = 0;
>> + 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:
>> @@ -757,6 +780,16 @@ static int params_from_supp(struct tee_param *params, size_t num_params,
>> p->u.value.b = ip.b;
>> p->u.value.c = ip.c;
>> break;
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
>> + case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT:
>> + p->u.ubuf.uaddr = u64_to_user_ptr(ip.a);
>> + p->u.ubuf.size = ip.b;
>> +
>> + if (!access_ok(params[n].u.ubuf.uaddr,
>> + params[n].u.ubuf.size))
>> + return -EFAULT;
>> +
>> + break;
>> case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
>> case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
>> /*
>> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
>> index a54c203000ed..78bbf12f02f0 100644
>> --- a/include/linux/tee_drv.h
>> +++ b/include/linux/tee_drv.h
>> @@ -82,6 +82,11 @@ struct tee_param_memref {
>> struct tee_shm *shm;
>> };
>> +struct tee_param_ubuf {
>> + void * __user uaddr;
>> + size_t size;
>> +};
>> +
>> struct tee_param_value {
>> u64 a;
>> u64 b;
>> @@ -92,6 +97,7 @@ struct tee_param {
>> u64 attr;
>> union {
>> struct tee_param_memref memref;
>> + struct tee_param_ubuf ubuf;
>> struct tee_param_value value;
>> } u;
>> };
>> diff --git a/include/uapi/linux/tee.h b/include/uapi/linux/tee.h
>> index d0430bee8292..3e9b1ec5dfde 100644
>> --- a/include/uapi/linux/tee.h
>> +++ b/include/uapi/linux/tee.h
>> @@ -151,6 +151,13 @@ struct tee_ioctl_buf_data {
>> #define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT 6
>> #define TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT 7 /* input and output */
>> +/*
>> + * These defines userspace buffer parameters.
>> + */
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT 8
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT 9
>> +#define TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INOUT 10 /* input and output */
>> +
>> /*
>> * Mask for the type part of the attribute, leaves room for more types
>> */
>> @@ -186,14 +193,17 @@ struct tee_ioctl_buf_data {
>> /**
>> * struct tee_ioctl_param - parameter
>> * @attr: attributes
>> - * @a: if a memref, offset into the shared memory object, else a value parameter
>> - * @b: if a memref, size of the buffer, else a value parameter
>> + * @a: if a memref, offset into the shared memory object,
>> + * else if a ubuf, address of the user buffer,
>> + * else a value parameter
>> + * @b: if a memref or ubuf, size of the buffer, else a value parameter
>> * @c: if a memref, shared memory identifier, else a value parameter
>> *
>> - * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref or value is used in
>> - * the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value and
>> - * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref. TEE_PARAM_ATTR_TYPE_NONE
>> - * indicates that none of the members are used.
>> + * @attr & TEE_PARAM_ATTR_TYPE_MASK indicates if memref, ubuf, or value is
>> + * used in the union. TEE_PARAM_ATTR_TYPE_VALUE_* indicates value,
>> + * TEE_PARAM_ATTR_TYPE_MEMREF_* indicates memref, and TEE_PARAM_ATTR_TYPE_UBUF_*
>> + * indicates ubuf. TEE_PARAM_ATTR_TYPE_NONE indicates that none of the members
>> + * are used.
>> *
>> * Shared memory is allocated with TEE_IOC_SHM_ALLOC which returns an
>> * identifier representing the shared memory object. A memref can reference
>>
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