[PATCH v8 5/8] arm64: cpufeature: Enumerate support for FEAT_ECV >= 0x2

[Reiji Watanabe]

On Thu, Sep 16, 2021 at 11:15 AM Oliver Upton <oupton at google.com> wrote:
>
> Introduce a new cpucap to indicate if the system supports full enhanced
> counter virtualization (i.e. ID_AA64MMFR0_EL1.ECV>=0x2).
>
> Signed-off-by: Oliver Upton <oupton at google.com>
> ---
>  arch/arm64/include/asm/sysreg.h |  1 +
>  arch/arm64/kernel/cpufeature.c  | 10 ++++++++++
>  arch/arm64/tools/cpucaps        |  1 +
>  3 files changed, 12 insertions(+)
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index b268082d67ed..3fa6b091384d 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -849,6 +849,7 @@
>  #define ID_AA64MMFR0_ASID_8            0x0
>  #define ID_AA64MMFR0_ASID_16           0x2
>
> +#define ID_AA64MMFR0_ECV_PHYS          0x2
>  #define ID_AA64MMFR0_TGRAN4_NI                 0xf
>  #define ID_AA64MMFR0_TGRAN4_SUPPORTED_MIN      0x0
>  #define ID_AA64MMFR0_TGRAN4_SUPPORTED_MAX      0x7
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index f8a3067d10c6..2f5042bb107c 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -2328,6 +2328,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
>                 .matches = has_cpuid_feature,
>                 .min_field_value = 1,
>         },
> +       {
> +               .desc = "Enhanced Counter Virtualization (Physical)",
> +               .capability = ARM64_HAS_ECV2,
> +               .type = ARM64_CPUCAP_SYSTEM_FEATURE,
> +               .sys_reg = SYS_ID_AA64MMFR0_EL1,
> +               .sign = FTR_UNSIGNED,
> +               .field_pos = ID_AA64MMFR0_ECV_SHIFT,
> +               .matches = has_cpuid_feature,
> +               .min_field_value = ID_AA64MMFR0_ECV_PHYS,
> +       },
>         {},
>  };
>
> diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
> index 49305c2e6dfd..f73a30d5fb1c 100644
> --- a/arch/arm64/tools/cpucaps
> +++ b/arch/arm64/tools/cpucaps
> @@ -18,6 +18,7 @@ HAS_CRC32
>  HAS_DCPODP
>  HAS_DCPOP
>  HAS_E0PD
> +HAS_ECV2
>  HAS_EPAN
>  HAS_GENERIC_AUTH
>  HAS_GENERIC_AUTH_ARCH
> --

Reviewed-by: Reiji Watanabe <reijiw at google.com>

Personally, I would prefer a more descriptive name (e.g. ECV_PHYS)
rather than ECV2 though.

Thanks,
Reiji