Re: [Qemu-devel] [PATCH] target-arm: make smc behave as a nop

[Rob Herring]

On Tue, Feb 11, 2014 at 5:29 PM, Peter Maydell <address@hidden> wrote:
> On 11 February 2014 23:19, Rob Herring <address@hidden> wrote:
>> From: Rob Herring <address@hidden>
>>
>> Several platforms make smc calls for things such as PL310 cache setup.
>> In these cases, making smc a nop rather than an illegal instruction
>> is sufficient for qemu to work.
>
> I can't remember if we've had this discussion before. Anyway,
> I think that making SMC NOP is too much of a platform-specific
> hack. If we want to support these platforms we need to either
> (a) implement TrustZone properly (b) implement some coherent
> mechanism for handing off SMCs to a bit of board specific firmware.
> (We might want the latter anyway for running these guests under
> KVM.)

I don't disagree and that is coming in some form with PSCI support,
but what do you gain in the meantime by platforms not booting. There
is no real usecase for faulting on smc's. I rather see code that works
on actual h/w work than correctly model in qemu code that doesn't work
on actual h/w.

Rob