Re: [PATCH v2 0/9] remoteproc: qcom_q6v5_wcss: add native ipq9574 support

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 1/15/26 6:27 AM, Alex G. wrote:
> On Wednesday, January 14, 2026 4:26:36 AM CST Konrad Dybcio wrote:
>> On 1/14/26 4:54 AM, Alex G. wrote:
>>> On Tuesday, January 13, 2026 8:28:11 AM CST Konrad Dybcio wrote:
>>>> On 1/9/26 5:33 AM, Alexandru Gagniuc wrote:
>>>>> Support loading remoteproc firmware on IPQ9574 with the qcom_q6v5_wcss
>>>>> driver. This firmware is usually used to run ath11k firmware and enable
>>>>> wifi with chips such as QCN5024.
>>>>>
>>>>> When submitting v1, I learned that the firmware can also be loaded by
>>>>> the trustzone firmware. Since TZ is not shipped with the kernel, it
>>>>> makes sense to have the option of a native init sequence, as not all
>>>>> devices come with the latest TZ firmware.
>>>>>
>>>>> Qualcomm tries to assure us that the TZ firmware will always do the
>>>>> right thing (TM), but I am not fully convinced
>>>>
>>>> Why else do you think it's there in the firmware? :(
>>>
>>> A more relevant question is, why do some contributors sincerely believe
>>> that the TZ initialization of Q6 firmware is not a good idea for their
>>> use case?
>>>
>>> To answer your question, I think the TZ initialization is an afterthought
>>> of the SoC design. I think it was only after ther the design stage that
>>> it was brought up that a remoteproc on AHB has out-of-band access to
>>> system memory, which poses security concerns to some customers. I think
>>> authentication was implemented in TZ to address that. I also think that
>>> in order to prevent clock glitching from bypassing such verification,
>>> they had to move the initialization sequence in TZ as well.
>>
>> I wouldn't exactly call it an afterthought.. Image authentication (as in,
>> verifying the signature of the ELF) has always been part of TZ, because
>> doing so in a user-modifiable context would be absolutely nonsensical
>>
>> qcom_scm_pas_auth_and_reset() which configures and powers up the rproc
>> has been there for a really long time too (at least since the 2012 SoCs
>> like MSM8974) and I would guesstimate it's been there for a reason - not
>> all clocks can or should be accessible from the OS (from a SW standpoint
>> it would be convenient to have a separate SECURE_CC block where all the
>> clocks we shouldn't care about are moved, but the HW design makes more
>> sense as-is, for the most part), plus there is additional access control
>> hardware on the platform that must be configured from a secure context
>> (by design) which I assume could be part of this sequence, based on
>> the specifics of a given SoC
> 
> What was the original use case for the Q6 remoteproc? I see today's use case 
> is as a conduit for ath11k firmware to control PCIe devices. Was that always 
> the case? I imagine a more modern design would treat the remoteproc as 
> untrusted by putting it under a bridge or IOMMU with more strict memory access 
> control, so that firmware couldn't access OS memory.

There is an SMMU on this SoC.

I don't know the original backstory, but if anything, the through-Q6
approach is probably *more* secure, since there's additional access
control hardware inbetween

Konrad