Re: [PATCH v2 13/14] arm64: rsi: Interfaces to query attestation token

[Suzuki K Poulose]

On 22/05/2024 16:52, Steven Price wrote:
> On 15/05/2024 12:10, Catalin Marinas wrote:
> > On Fri, Apr 12, 2024 at 09:42:12AM +0100, Steven Price wrote:
> > > diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
> > > index b4cbeafa2f41..c1850aefe54e 100644
> > > --- a/arch/arm64/include/asm/rsi_cmds.h
> > > +++ b/arch/arm64/include/asm/rsi_cmds.h
> > > @@ -10,6 +10,9 @@
> > >   
> > >   #include <asm/rsi_smc.h>
> > >   
> > > +#define GRANULE_SHIFT		12
> > > +#define GRANULE_SIZE		(_AC(1, UL) << GRANULE_SHIFT)
> >
> > The name is too generic and it goes into a header file. Also maybe move
> > it to rsi.h, and use it for other definitions like rsi_config struct
> > size and alignment.
>
> The realm config structure although it 'happens to be' granule sized
> isn't really required to be - so I think it would be a bit confusing to
> specify that.

The struct realm_config must be aligned to GRANULE_SIZE and the argument
must be as such aligned.

> There are only two other interfaces that require this:
>   * RSI_IPA_STATE_GET - completely unused so far
>   * RSI_ATTESTATION_TOKEN_CONTINUE - the buffer has to be contained with
>     a granule, so it affects the maximum length per operation.
>
> I'll rename to RSI_GRANULE_{SHIFT,SIZE}, but I'm not sure it really

That looks good to me.

Suzuki


> belongs in rsi.h because none of that functionality cares about the
> granule size (indeed the driver in the following patch doesn't include
> rsi.h).
>
> Thanks,
> Steve