Subject: Re: [PATCH v2 1/5] arm64/sysreg: Add HDBSS related register information

From: Marc Zyngier <[email-masked]>
Date: Sat, 22 Nov 2025 12:40:27 +0000

On Fri, 21 Nov 2025 09:23:38 +0000,
Tian Zheng <[email-masked]> wrote:
> 
> From: eillon <[email-masked]>
> 
> The ARM architecture added the HDBSS feature and descriptions of
> related registers (HDBSSBR/HDBSSPROD) in the DDI0601(ID121123) version,
> add them to Linux.
> 
> Signed-off-by: eillon <[email-masked]>
> Signed-off-by: Tian Zheng <[email-masked]>
> ---
>  arch/arm64/include/asm/esr.h     |  2 ++
>  arch/arm64/include/asm/kvm_arm.h |  1 +
>  arch/arm64/tools/sysreg          | 28 ++++++++++++++++++++++++++++
>  3 files changed, 31 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> index e1deed824464..a6f3cf0b9b86 100644
> --- a/arch/arm64/include/asm/esr.h
> +++ b/arch/arm64/include/asm/esr.h
> @@ -159,6 +159,8 @@
>  #define ESR_ELx_CM 		(UL(1) << ESR_ELx_CM_SHIFT)
> 
>  /* ISS2 field definitions for Data Aborts */
> +#define ESR_ELx_HDBSSF_SHIFT	(11)
> +#define ESR_ELx_HDBSSF		(UL(1) << ESR_ELx_HDBSSF_SHIFT)
>  #define ESR_ELx_TnD_SHIFT	(10)
>  #define ESR_ELx_TnD 		(UL(1) << ESR_ELx_TnD_SHIFT)
>  #define ESR_ELx_TagAccess_SHIFT	(9)
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 1da290aeedce..b71122680a03 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -124,6 +124,7 @@
>  			 TCR_EL2_ORGN0_MASK | TCR_EL2_IRGN0_MASK)
> 
>  /* VTCR_EL2 Registers bits */
> +#define VTCR_EL2_HDBSS		(1UL << 45)

I think it is time to convert VTCR_EL2 to the sysreg infrastructure
instead of adding extra bits here.

	M.

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