Re: [RFC PATCH v1 11/38] KVM: arm64: CCA: register host tsm platform device

[Jeremy Linton]

On 10/10/25 10:30 AM, Jason Gunthorpe wrote:
> On Fri, Oct 10, 2025 at 10:28:36AM -0500, Jeremy Linton wrote:
>
> > > So you could use auxiliary_device, you'd consider SMC itself to be the
> > > shared HW block and all the auxiliary drivers are per-subsystem
> > > aspects of that shared SMC interface. It is not a terrible fit for
> > > what it was intended for at least.
> >
> > Turns out that changing any of this, will at the moment break systemd's
> > confidential vm detection, because they wanted the earliest indicator the
> > guest was capable and that turned out to be this platform device.
>
> Having systemd detect a software created platform device sounds
> compltely crazy, don't do that. Make a proper sysfs uapi for such a
> general idea please.

Yes, I agree, its just at the time the statment was around what is the 
most reliable early indicator, and since there isn't a hwcap or anything 
that ended up being the choice, as disgusting as it is.

Presumably once all this works out the sysfs/api surface will be more 
'defined'


> Jason