Re: [PATCH 1/4] KVM: arm64: Enable Pointer Authentication at EL2 if available

Andrew Scull
2020-06-15T08:49:05Z

On Mon, Jun 15, 2020 at 09:19:51AM +0100, Marc Zyngier wrote:
> While initializing EL2, switch Pointer Authentication if detected

^ nit: on?

> from EL1. We use the EL1-provided keys though.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> arch/arm64/kvm/hyp-init.S | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
> index 6e6ed5581eed..81732177507d 100644
> --- a/arch/arm64/kvm/hyp-init.S
> +++ b/arch/arm64/kvm/hyp-init.S
> @@ -104,6 +104,17 @@ alternative_else_nop_endif
> */
> mov_q x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
> CPU_BE( orr x4, x4, #SCTLR_ELx_EE)
> +alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
> + b 1f
> +alternative_else_nop_endif
> +alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
> + b 2f
> +alternative_else_nop_endif
> +1:
> + orr x4, x4, #(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB)
> + orr x4, x4, #SCTLR_ELx_ENDA
> + orr x4, x4, #SCTLR_ELx_ENDB

mm/proc.S builds the mask with ldr and ors it in one go, would be nice
to use the same pattern.

> +2:
> msr sctlr_el2, x4
> isb

Acked-by: Andrew Scull <ascull@google.com>