On Fri, Jun 20, 2025 at 10:13:01PM +0000, Colton Lewis wrote:
> Add a capability for FEAT_HPMN0, whether MDCR_EL2.HPMN can specify 0
> counters reserved for the guest.
>
> This required changing HPMN0 to an UnsignedEnum in tools/sysreg
> because otherwise not all the appropriate macros are generated to add
> it to arm64_cpu_capabilities_arm64_features.
>
> Signed-off-by: Colton Lewis <coltonlewis@xxxxxxxxxx>
> ---
> arch/arm64/kernel/cpufeature.c | 8 ++++++++
> arch/arm64/tools/cpucaps | 1 +
> arch/arm64/tools/sysreg | 6 +++---
> 3 files changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index b34044e20128..278294fdc97d 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -548,6 +548,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = {
> };
>
> static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
> + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_HPMN0_SHIFT, 4, 0),
> S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_DoubleLock_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_PMSVer_SHIFT, 4, 0),
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_CTX_CMPs_SHIFT, 4, 0),
> @@ -2896,6 +2897,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
> .matches = has_cpuid_feature,
> ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, FGT, FGT2)
> },
> + {
> + .desc = "Allow MDCR_EL2.HPMN = 0",
This feedback still stands...
.desc = "HPMN0",
[*] https://lore.kernel.org/kvm/aD4ijUaSGm9b2g5H@xxxxxxxxx/
> + .type = ARM64_CPUCAP_SYSTEM_FEATURE,
> + .capability = ARM64_HAS_HPMN0,
> + .matches = has_cpuid_feature,
> + ARM64_CPUID_FIELDS(ID_AA64DFR0_EL1, HPMN0, IMP)
> + },
> #ifdef CONFIG_ARM64_SME
> {
> .desc = "Scalable Matrix Extension",
> diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
> index 10effd4cff6b..5b196ba21629 100644
> --- a/arch/arm64/tools/cpucaps
> +++ b/arch/arm64/tools/cpucaps
> @@ -39,6 +39,7 @@ HAS_GIC_CPUIF_SYSREGS
> HAS_GIC_PRIO_MASKING
> HAS_GIC_PRIO_RELAXED_SYNC
> HAS_HCR_NV1
> +HAS_HPMN0
> HAS_HCX
> HAS_LDAPR
> HAS_LPA2
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index 8a8cf6874298..d29742481754 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -1531,9 +1531,9 @@ EndEnum
> EndSysreg
>
> Sysreg ID_AA64DFR0_EL1 3 0 0 5 0
> -Enum 63:60 HPMN0
> - 0b0000 UNPREDICTABLE
> - 0b0001 DEF
> +UnsignedEnum 63:60 HPMN0
> + 0b0000 NI
> + 0b0001 IMP
> EndEnum
> UnsignedEnum 59:56 ExtTrcBuff
> 0b0000 NI
> --
> 2.50.0.714.g196bf9f422-goog
>
