Re: [PATCH 6/6] target/arm: Support PAuth extension for hvf

[Peter Maydell]

On Sun, 6 Feb 2022 at 00:26, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 2/5/22 03:55, Peter Maydell wrote:
> > Currently we don't allow guests under hvf to use the PAuth extension,
> > because we didn't have any special code to handle that, and therefore
> > in arm_cpu_pauth_finalize() we will sanitize the ID_AA64ISAR1 value
> > the guest sees to clear the PAuth related fields.
> >
> > Add support for this in the same way that KVM does it, by defaulting
> > to "PAuth enabled" if the host CPU has it and allowing the user to
> > disable it via '-cpu pauth=no' on the command line.
> >
> > Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> > ---
> >   target/arm/cpu64.c | 14 ++++++++++----
> >   1 file changed, 10 insertions(+), 4 deletions(-)
>
> Currently not a problem in practice because M1 doesn't support PAuth, so the 
> ID fields are
> already clear.  However, it is a confusing difference to kvm, and presumably 
> some future
> Apple chip will enable PAuth.

No, this is an actual bug that was reported to me. The M1
does support PAuth, with an IMPDEF algorithm (and no
support for QARMA5), and we were suppressing this by
clearing the ID register fields.

thanks
-- PMM