[PATCH 2/2] kvm/arm64: Detach ESR operator from vCPU struct
Mark Rutland
mark.rutland at arm.com
Mon Jun 29 07:00:16 EDT 2020
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 at redhat.com>
TBH, I'm not sure that this patch makes much sense on its own.
We already use vcpu_get_esr(), which is the bit that'd have to change if
we didn't pass the vcpu around, and the new helpers are just consuming
the value in a sifferent way rather than a necessarily simpler way.
Further comments on that front below.
> ---
> 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)); \
> +}
> +
> +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);
I'm really not keen on this, as I think it's abstracting the problem at
the wrong level, hiding information and making things harder to reason
about rather than abstracting that.
I strongly suspect the right thing to do is use FIELD_GET() in-place in
the functions below, e.g.
!!FIELD_GET(esr, ESR_ELx_IL);
... rather than:
esr_get_il_32bit(esr);
... as that avoids the wrapper entirely, minimizing indirection and
making the codebase simpler to navigate.
For the cases where we *really* want a helper, i'd rather write those
out explicitly, e.g.
#define esr_get_hvc_imm(esr) FIELD_GET(esr, ESR_ELx_xVC_IMM_MASK)
... but I'm not sure if we really need those given these are mostly used
*once* below.
> +
> 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;
> }
Do we really need to change the structure of this code? I thought this
was purely about decooupling helpers from the vcpu struct. This could
have stayed as:
static __always_inline int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu)
{
u32 esr = kvm_vcpu_get_esr(vcpu);
if (esr_is_condition(esr))
return esr_get_condition(esr);
return -1;
}
... or:
static __always_inline int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu)
{
u32 esr = kvm_vcpu_get_esr(vcpu);
if (FEILD_GET(esr, ESR_ELx_CV))
return FIELD_GET(esr, ESR_ELx_COND_MASK);
return -1;
}
Thanks,
Mark.
>
> 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));
> }
>
> 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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