Re: [kvm-unit-tests PATCH v1 7/7] arm64: run at EL2 if supported

[Marc Zyngier <maz@kernel.org>]

On Thu, 20 Feb 2025 14:13:54 +0000,
Joey Gouly <joey.gouly@arm.com> wrote:
> 
> If VHE is supported, continue booting at EL2, otherwise continue booting at
> EL1.
> 
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> ---
>  arm/cstart64.S         | 28 ++++++++++++++++++++++++++++
>  lib/arm64/asm/sysreg.h |  5 +++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/arm/cstart64.S b/arm/cstart64.S
> index 3a305ad0..2a15c03d 100644
> --- a/arm/cstart64.S
> +++ b/arm/cstart64.S
> @@ -68,6 +68,20 @@ reloc_done:
>  	mrs	x4, CurrentEL
>  	cmp	x4, CurrentEL_EL2
>  	b.ne	1f
> +	/* EL2 setup */
> +	mrs	x4, mpidr_el1
> +	msr	vmpidr_el2, x4
> +	mrs	x4, midr_el1
> +	msr	vpidr_el2, x4
> +	/* check VHE is supported */
> +	mrs	x4, ID_AA64MMFR1_EL1
> +	ubfx	x4, x4, ID_AA64MMFR1_EL1_VH_SHIFT, #4
> +	cmp	x4, #0
> +	b.eq	drop_to_el1

nit: you can replace these cmp/b.eq with a cbz.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.