[PATCH v9 01/22] arm64: cpufeature: Add cpucap for HPMN0
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COOLING5d
REVIEWED: 10 (10M)
From: Colton Lewis <hidden>
Date: 2026-09-24 17:29:33
Also in:
kvm, kvmarm, linux-doc, linux-kselftest, linux-perf-users, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Revision v9 of 9 in this series; 2 review trailers (2 from subsystem maintainers).
Revisions (9)
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. Acked-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Colton Lewis <redacted> --- arch/arm64/kernel/cpufeature.c | 10 +++++++++- arch/arm64/kvm/sys_regs.c | 5 ++++- arch/arm64/tools/cpucaps | 1 + arch/arm64/tools/sysreg | 6 +++--- 4 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 32102c3912fa7..f8431cf858619 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -77,7 +77,7 @@ #include <linux/percpu.h> #include <linux/sched/isolation.h> -#include <asm/arm_pmuv3.h> +#include <linux/perf/arm_pmuv3.h> #include <asm/cpu.h> #include <asm/cpufeature.h> #include <asm/cpu_ops.h>
@@ -564,6 +564,7 @@ static const struct arm64_ftr_bits ftr_id_mmfr0[] = { }; static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, 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),
@@ -3012,6 +3013,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, FGT, FGT2) }, + { + .desc = "HPMN0", + .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/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 44aae52c473d7..f7f750b7a91c4 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c@@ -2219,6 +2219,8 @@ static u64 sanitise_id_aa64dfr0_el1(const struct kvm_vcpu *vcpu, u64 val) if (kvm_vcpu_has_pmu(vcpu)) val |= SYS_FIELD_PREP(ID_AA64DFR0_EL1, PMUVer, kvm_arm_pmu_get_pmuver_limit()); + else + val &= ~ID_AA64DFR0_EL1_HPMN0_MASK; /* Hide SPE from guests */ val &= ~ID_AA64DFR0_EL1_PMSVer_MASK;
@@ -3417,7 +3419,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { ID_AA64DFR0_EL1_DoubleLock_MASK | ID_AA64DFR0_EL1_WRPs_MASK | ID_AA64DFR0_EL1_PMUVer_MASK | - ID_AA64DFR0_EL1_DebugVer_MASK), + ID_AA64DFR0_EL1_DebugVer_MASK | + ID_AA64DFR0_EL1_HPMN0_MASK), ID_SANITISED(ID_AA64DFR1_EL1), ID_UNALLOCATED(5,2), ID_UNALLOCATED(5,3),
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 2775ba3359cfe..a309c18235e71 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps@@ -43,6 +43,7 @@ HAS_GIC_PRIO_MASKING HAS_GIC_PRIO_RELAXED_SYNC HAS_ICH_HCR_EL2_TDIR HAS_HCR_NV1 +HAS_HPMN0 HAS_HCX HAS_LDAPR HAS_LPA2
diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index e2d37ee221b84..1035b406ef183 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg@@ -1679,9 +1679,9 @@ 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
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2.56.0.rc1.310.g51773c2048-goog