On Thu, 10 Oct 2024 08:33:13 +0100,
Oliver Upton <oliver.upton@xxxxxxxxx> wrote:
>
> On Wed, Oct 09, 2024 at 08:00:03PM +0100, Marc Zyngier wrote:
> > S1PIE implicitly disables hierarchical permissions, as specified in
> > R_JHSVW, by making TCR_ELx.HPDn RES1.
> >
> > Add a predicate for S1PIE being enabled for a given translation regime,
> > and emulate this behaviour by forcing the hpd field to true if S1PIE
> > is enabled for that translation regime.
> >
> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/at.c | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
> > index adcfce3f67f03..f5bd750288ff5 100644
> > --- a/arch/arm64/kvm/at.c
> > +++ b/arch/arm64/kvm/at.c
> > @@ -93,6 +93,23 @@ static enum trans_regime compute_translation_regime(struct kvm_vcpu *vcpu, u32 o
> > }
> > }
> >
> > +static bool s1pie_enabled(struct kvm_vcpu *vcpu, enum trans_regime regime)
> > +{
> > + if (!kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, S1PIE, IMP))
> > + return false;
> > +
> > + switch (regime) {
> > + case TR_EL2:
> > + case TR_EL20:
> > + return vcpu_read_sys_reg(vcpu, TCR2_EL2) & TCR2_EL2_PIE;
> > + case TR_EL10:
> > + return (__vcpu_sys_reg(vcpu, HCRX_EL2) & HCRX_EL2_TCR2En) &&
> > + (__vcpu_sys_reg(vcpu, TCR2_EL1) & TCR2_EL1x_PIE);
> > + default:
> > + BUG();
>
> BUILD_BUG()?
Doesn't work. regime is fished out of the walk_info structure, meaning
that it is pretty opaque to the compiler, which in turn needs to emit
code for all cases.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
