Re: [PATCH v7 10/11] qcomtee: enable TEE_IOC_SHM_ALLOC ioctl

[Konrad Dybcio]

On 8/14/25 1:19 AM, Amirreza Zarrabi wrote:
> 
> 
> On 8/14/2025 8:49 AM, Konrad Dybcio wrote:
>> On 8/14/25 12:24 AM, Amirreza Zarrabi wrote:
>>>
>>>
>>> On 8/13/2025 8:00 PM, Konrad Dybcio wrote:
>>>> On 8/13/25 2:35 AM, Amirreza Zarrabi wrote:
>>>>> Enable userspace to allocate shared memory with QTEE. Since
>>>>> QTEE handles shared memory as object, a wrapper is implemented
>>>>> to represent tee_shm as an object. The shared memory identifier,
>>>>> obtained through TEE_IOC_SHM_ALLOC, is transferred to the driver using
>>>>> TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT/OUTPUT.
>>>>>
>>>>> Tested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
>>>>> Acked-by: Sumit Garg <sumit.garg@xxxxxxxxxxxxxxxx>
>>>>> Tested-by: Harshal Dev <quic_hdev@xxxxxxxxxxx>
>>>>> Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>
>>>>> ---
>>>>
>>>> [...]
>>>>
>>>>> +/* Mapping information format as expected by QTEE. */
>>>>> +struct qcomtee_mapping_info {
>>>>> +	u64 paddr;
>>>>> +	u64 len;
>>>>> +	u32 perms;
>>>>> +} __packed;
>>>>
>>>> Please use types with explicit endianness, e.g. __le32. I'm assuming
>>>> TZ will always be little-endian, regardless of the host OS
>>>>
>>>
>>> I'm not entirely sure how this point is relevant. As I understand it,
>>> the core that populates this struct is the same one that accesses it in TZ.
>>> Your argument would absolutely make sense if the host and TZ were operating
>>> on different cores with distinct architectures -- such as one being
>>> little-endian and the other big-endian, which is not the case.
>>
>> CONFIG_CPU_BIG_ENDIAN=y exists on arm64
>>
> 
> Or, you are saying we may have a configuration where host is big-endian
> but TZ is little-endian?

I was indeed about to say that.. I believe our tz is always little-endian
but you can run the HLOS of either endianness

Konrad