[PATCH 02/13] KVM: arm64: Clarify ESR_ELx_ERET_ISS_ERET*

[Joey Gouly]

On Mon, Feb 19, 2024 at 09:20:03AM +0000, Marc Zyngier wrote:
> The ESR_ELx_ERET_ISS_ERET* macros are a bit confusing:
> 
> - ESR_ELx_ERET_ISS_ERET really indicates that we have trapped an
>   ERETA* instruction, as opposed to an ERET
> 
> - ESR_ELx_ERET_ISS_ERETA reallu indicates that we have trapped
>   an ERETAB instruction, as opposed to an ERETAA.
> 
> Repaint the two helpers such as:
> 
> - ESR_ELx_ERET_ISS_ERET becomes ESR_ELx_ERET_ISS_ERETA
> 
> - ESR_ELx_ERET_ISS_ERETA becomes ESR_ELx_ERET_ISS_ERETAB
> 
> At the same time, use BIT() instead of raw values.
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>

I'm somewhat against this, as the original names are what the Arm ARM specifies.

> ---
>  arch/arm64/include/asm/esr.h | 4 ++--
>  arch/arm64/kvm/handle_exit.c | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> index 353fe08546cf..72c7810ccf2c 100644
> --- a/arch/arm64/include/asm/esr.h
> +++ b/arch/arm64/include/asm/esr.h
> @@ -290,8 +290,8 @@
>  		 ESR_ELx_SYS64_ISS_OP2_SHIFT))
>  
>  /* ISS field definitions for ERET/ERETAA/ERETAB trapping */
> -#define ESR_ELx_ERET_ISS_ERET		0x2
> -#define ESR_ELx_ERET_ISS_ERETA		0x1
> +#define ESR_ELx_ERET_ISS_ERETA		BIT(1)
> +#define ESR_ELx_ERET_ISS_ERETAB		BIT(0)
>  
>  /*
>   * ISS field definitions for floating-point exception traps
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 617ae6dea5d5..0646c623d1da 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -219,7 +219,7 @@ static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu)
>  
>  static int kvm_handle_eret(struct kvm_vcpu *vcpu)
>  {
> -	if (kvm_vcpu_get_esr(vcpu) & ESR_ELx_ERET_ISS_ERET)
> +	if (kvm_vcpu_get_esr(vcpu) & ESR_ELx_ERET_ISS_ERETA)

If this part is confusing due to the name, maybe introduce a function in esr.h
esr_is_pac_eret() (name pending bikeshedding)?

>  		return kvm_handle_ptrauth(vcpu);
>  
>  	/*

Thanks,
Joey