Re: [PATCH v4 22/24] powerpc/pseries: Implement secvars for dynamic secure boot

Andrew Donnellan
2023-02-01T02:16:54Z

On Tue, 2023-01-31 at 18:55 +1000, Nicholas Piggin wrote:
> > > > +       var.datalen = 1;
> > > > +       var.data = kzalloc(1, GFP_KERNEL);
> > >
> > > This could just point to a u8 on stack I think?
> >
> > Until we get VMAP_STACK and we'll have to switch back.
>
> AFAIKS plpks_read_var does not require linear map, so should not be
> required. IMO that's the right way to go for an external API, so
> actually plpks_write_var is the outlier there and should be changed
> to follow read and remove in not requiring special pointers.

Indeed, I was confused - in the read case, the buffer doesn't get
directly passed to the hcall.

I'll wait a little bit longer for more feedback on v5 of this series
and maybe fix this in v6 if mpe thinks I should respin it again.

--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited