Re: [PATCH 2/2] kvm/arm64: Detach ESR operator from vCPU struct

[Andrew Scull <ascull@google.com>]

On Mon, Jun 29, 2020 at 07:18:41PM +1000, Gavin Shan wrote:
> There are a set of inline functions defined in kvm_emulate.h. Those
> functions reads ESR from vCPU fault information struct and then operate
> on it. So it's tied with vCPU fault information and vCPU struct. It
> limits their usage scope.
> 
> This detaches these functions from the vCPU struct by introducing an
> other set of inline functions in esr.h to manupulate the specified
> ESR value. With it, the inline functions defined in kvm_emulate.h
> can call these inline functions (in esr.h) instead. This shouldn't
> cause any functional changes.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  arch/arm64/include/asm/esr.h         | 32 +++++++++++++++++++++
>  arch/arm64/include/asm/kvm_emulate.h | 43 ++++++++++++----------------
>  2 files changed, 51 insertions(+), 24 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> index 035003acfa87..950204c5fbe1 100644
> --- a/arch/arm64/include/asm/esr.h
> +++ b/arch/arm64/include/asm/esr.h
> @@ -326,6 +326,38 @@ static inline bool esr_is_data_abort(u32 esr)
>  	return ec == ESR_ELx_EC_DABT_LOW || ec == ESR_ELx_EC_DABT_CUR;
>  }
>  
> +#define ESR_DECLARE_CHECK_FUNC(name, field)	\
> +static inline bool esr_is_##name(u32 esr)	\
> +{						\
> +	return !!(esr & (field));		\
> +}
> +#define ESR_DECLARE_GET_FUNC(name, mask, shift)	\
> +static inline u32 esr_get_##name(u32 esr)	\
> +{						\
> +	return ((esr & (mask)) >> (shift));	\
> +}

Should these be named DEFINE rather than DECLARE given it also includes
the function definition?

> +
> +ESR_DECLARE_CHECK_FUNC(il_32bit,   ESR_ELx_IL);
> +ESR_DECLARE_CHECK_FUNC(condition,  ESR_ELx_CV);
> +ESR_DECLARE_CHECK_FUNC(dabt_valid, ESR_ELx_ISV);
> +ESR_DECLARE_CHECK_FUNC(dabt_sse,   ESR_ELx_SSE);
> +ESR_DECLARE_CHECK_FUNC(dabt_sf,    ESR_ELx_SF);
> +ESR_DECLARE_CHECK_FUNC(dabt_s1ptw, ESR_ELx_S1PTW);
> +ESR_DECLARE_CHECK_FUNC(dabt_write, ESR_ELx_WNR);
> +ESR_DECLARE_CHECK_FUNC(dabt_cm,    ESR_ELx_CM);
> +
> +ESR_DECLARE_GET_FUNC(class,        ESR_ELx_EC_MASK,      ESR_ELx_EC_SHIFT);
> +ESR_DECLARE_GET_FUNC(fault,        ESR_ELx_FSC,          0);
> +ESR_DECLARE_GET_FUNC(fault_type,   ESR_ELx_FSC_TYPE,     0);
> +ESR_DECLARE_GET_FUNC(condition,    ESR_ELx_COND_MASK,    ESR_ELx_COND_SHIFT);
> +ESR_DECLARE_GET_FUNC(hvc_imm,      ESR_ELx_xVC_IMM_MASK, 0);
> +ESR_DECLARE_GET_FUNC(dabt_iss_nisv_sanitized,
> +		     (ESR_ELx_CM | ESR_ELx_WNR | ESR_ELx_FSC), 0);
> +ESR_DECLARE_GET_FUNC(dabt_rd,      ESR_ELx_SRT_MASK,     ESR_ELx_SRT_SHIFT);
> +ESR_DECLARE_GET_FUNC(dabt_as,      ESR_ELx_SAS,          ESR_ELx_SAS_SHIFT);
> +ESR_DECLARE_GET_FUNC(sys_rt,       ESR_ELx_SYS64_ISS_RT_MASK,
> +				   ESR_ELx_SYS64_ISS_RT_SHIFT);
> +
>  const char *esr_get_class_string(u32 esr);
>  #endif /* __ASSEMBLY */
>  
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index c9ba0df47f7d..9337d90c517f 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -266,12 +266,8 @@ static __always_inline u32 kvm_vcpu_get_esr(const struct kvm_vcpu *vcpu)
>  
>  static __always_inline int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu)
>  {
> -	u32 esr = kvm_vcpu_get_esr(vcpu);
> -
> -	if (esr & ESR_ELx_CV)
> -		return (esr & ESR_ELx_COND_MASK) >> ESR_ELx_COND_SHIFT;
> -
> -	return -1;
> +	return esr_is_condition(kvm_vcpu_get_esr(vcpu)) ?
> +	       esr_get_condition(kvm_vcpu_get_esr(vcpu)) : -1;
>  }
>  
>  static __always_inline unsigned long kvm_vcpu_get_hfar(const struct kvm_vcpu *vcpu)
> @@ -291,79 +287,79 @@ static inline u64 kvm_vcpu_get_disr(const struct kvm_vcpu *vcpu)
>  
>  static inline u32 kvm_vcpu_hvc_get_imm(const struct kvm_vcpu *vcpu)
>  {
> -	return kvm_vcpu_get_esr(vcpu) & ESR_ELx_xVC_IMM_MASK;
> +	return esr_get_hvc_imm(kvm_vcpu_get_esr(vcpu));
>  }

It feels a little strange that in the raw esr case it uses macro magic
but in the vcpu cases here it writes everything out in full. Was there a
reason that I'm missing or is there a chance to apply a consistent
approach?

I'm not sure of the style preferences, but if it goes the macro path,
the esr field definitions could be reused with something x-macro like to
get the kvm_emulate.h and esr.h functions generated from a singe list of
the esr fields.

>  static __always_inline bool kvm_vcpu_dabt_isvalid(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_ISV);
> +	return esr_is_dabt_valid(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static inline unsigned long kvm_vcpu_dabt_iss_nisv_sanitized(const struct kvm_vcpu *vcpu)
>  {
> -	return kvm_vcpu_get_esr(vcpu) & (ESR_ELx_CM | ESR_ELx_WNR | ESR_ELx_FSC);
> +	return esr_get_dabt_iss_nisv_sanitized(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static inline bool kvm_vcpu_dabt_issext(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_SSE);
> +	return esr_is_dabt_sse(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static inline bool kvm_vcpu_dabt_issf(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_SF);
> +	return esr_is_dabt_sf(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline int kvm_vcpu_dabt_get_rd(const struct kvm_vcpu *vcpu)
>  {
> -	return (kvm_vcpu_get_esr(vcpu) & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT;
> +	return esr_get_dabt_rd(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline bool kvm_vcpu_dabt_iss1tw(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_S1PTW);
> +	return esr_is_dabt_s1ptw(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline bool kvm_vcpu_dabt_iswrite(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_WNR) ||
> -		kvm_vcpu_dabt_iss1tw(vcpu); /* AF/DBM update */
> +	return esr_is_dabt_write(kvm_vcpu_get_esr(vcpu)) ||
> +	       esr_is_dabt_s1ptw(kvm_vcpu_get_esr(vcpu)); /* AF/DBM update */
>  }
>  
>  static inline bool kvm_vcpu_dabt_is_cm(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_CM);
> +	return esr_is_dabt_cm(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline unsigned int kvm_vcpu_dabt_get_as(const struct kvm_vcpu *vcpu)
>  {
> -	return 1 << ((kvm_vcpu_get_esr(vcpu) & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT);
> +	return 1 << esr_get_dabt_as(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  /* This one is not specific to Data Abort */
>  static __always_inline bool kvm_vcpu_trap_il_is32bit(const struct kvm_vcpu *vcpu)
>  {
> -	return !!(kvm_vcpu_get_esr(vcpu) & ESR_ELx_IL);
> +	return esr_is_il_32bit(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline u8 kvm_vcpu_trap_get_class(const struct kvm_vcpu *vcpu)
>  {
> -	return ESR_ELx_EC(kvm_vcpu_get_esr(vcpu));
> +	return esr_get_class(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static inline bool kvm_vcpu_trap_is_iabt(const struct kvm_vcpu *vcpu)
>  {
> -	return kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_IABT_LOW;
> +	return esr_get_class(kvm_vcpu_get_esr(vcpu)) == ESR_ELx_EC_IABT_LOW;
>  }
>  
>  static __always_inline u8 kvm_vcpu_trap_get_fault(const struct kvm_vcpu *vcpu)
>  {
> -	return kvm_vcpu_get_esr(vcpu) & ESR_ELx_FSC;
> +	return esr_get_fault(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline u8 kvm_vcpu_trap_get_fault_type(const struct kvm_vcpu *vcpu)
>  {
> -	return kvm_vcpu_get_esr(vcpu) & ESR_ELx_FSC_TYPE;
> +	return esr_get_fault_type(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static __always_inline bool kvm_vcpu_dabt_isextabt(const struct kvm_vcpu *vcpu)
> @@ -387,8 +383,7 @@ static __always_inline bool kvm_vcpu_dabt_isextabt(const struct kvm_vcpu *vcpu)
>  
>  static __always_inline int kvm_vcpu_sys_get_rt(struct kvm_vcpu *vcpu)
>  {
> -	u32 esr = kvm_vcpu_get_esr(vcpu);
> -	return ESR_ELx_SYS64_ISS_RT(esr);
> +	return esr_get_sys_rt(kvm_vcpu_get_esr(vcpu));
>  }
>  
>  static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
> -- 
> 2.23.0
> 
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