Re: [RFC PATCH 0/3] initalise ff-a after finalising pKVM

On Tue, May 05, 2026 at 10:54:06AM +0100, Yeoreum Yun wrote:
> This patch is split out from the patchset [0] --
> fix FF-A call failure with pKVM when the FF-A driver is built-in,
> specifically the IMA-related part.
> 
> When pKVM is enabled, the FF-A driver must be initialised after pKVM.
> Otherwise, pKVM cannot negotiate the FF-A version or obtain the RX/TX
> buffer information, leading to failures in FF-A calls.
> 
> Currently, pKVM initialisation completes at device_initcall_sync,
> while ffa_init() runs at the device_initcall level.
> 
> So far, linker deployes kvm_arm_init() before ffa_init(), and SMCs can
> still be trapped even before finalise_pkvm() is invoked.
> As a result, this issue has not been observed.
> 
> However, relying on above stuff is fragile.
> Therefore, when pKVM is enabled, the FF-A infrastructure should be
> initialised only after pKVM initialisation has been fully finalised.
> 
> To achieve this, introduce an ffa_root_dev ("arm-ffa") and
> a corresponding driver to defer initialisation of the FF-A infrastructure
> until pKVM initialisation is complete, and to defer probing of all FF-A devices until then
> when pKVM is enabled.
>

I have posted an alternative based on all the discussion in this thread
@[1]. I have not cc-ed all the people as the changes are contained in
FF-A driver and not sure if all the cc-ed here are much interested.
All the lists are included I assume and one can always provide feedback
referring to the link.

-- 
Regards,
Sudeep

[1] https://lore.kernel.org/all/[email protected]/