Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver

Yeoreum Yun
2026-04-20T13:01:14Z

Hi Sebastian,
> On Fri, Apr 17, 2026 at 06:57:59PM +0100, Yeoreum Yun wrote:
>
> Hello Yeoreum,
>
>
> > When pKVM is enabled, the FF-A driver must be initialized after pKVM.
> > Otherwise, pKVM cannot negotiate the FF-A version or
> > obtain RX/TX buffer information, leading to failures in FF-A calls.
>
> At the moment this already happens after you move back ffa_init() to
> device_initcall().

How? the kvm_arm_init() is device_initcall() if both built as built-in.

>
> >
> > During FF-A driver initialization, check whether pKVM has been initialized.
> > If not, defer probing of the FF-A driver.
> >
>
> I don't think you need to add this dependency. pKVM is
> installed through KVM's module_init() which ends up calling hyp_ffa_init() to
> do the proxy initialization. The ARM-FFA driver comes after it (since
> pKVM is arch specific code). We don't have to call finalize_pkvm(..) to
> be able to handle smc(FF-A) calls in the hyp-proxy.
>

As Marc said, the before finalised_pkvm(), smc wouldn't be trapped
to pKVM. IOW, in case when both built as built-in,
if ffa_init() is called before finalised_pkvm(),
it couldn't proxy the FFA_VERSION, FFA_RXTX_MAP and FFA_PARTITION_INFO_GET
called by ffa_init().

How can you gurantee hyp_ffa_init() which is called by kvm_arm_init()
comes first even kvm_arm_init() and ffa_init() are on device_initcall?

[...]

Thanks

--
Sincerely,
Yeoreum Yun