From 75ecffc361bbc85696c084f3d3c73eb207386e3f Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:28 -0800 Subject: [PATCH 01/14] drivers/perf: apple_m1: Refactor event select/filter configuration Supporting guest mode events will necessitate programming two event filters. Prepare by splitting up the programming of the event selector + event filter into separate headers. Opportunistically replace RMW patterns with sysreg_clear_set_s(). Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-2-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- drivers/perf/apple_m1_cpu_pmu.c | 52 ++++++++++++++++++++------------- 1 file changed, 32 insertions(+), 20 deletions(-) diff --git a/drivers/perf/apple_m1_cpu_pmu.c b/drivers/perf/apple_m1_cpu_pmu.c index 06fd317529fcb..cea80afd12537 100644 --- a/drivers/perf/apple_m1_cpu_pmu.c +++ b/drivers/perf/apple_m1_cpu_pmu.c @@ -327,11 +327,10 @@ static void m1_pmu_disable_counter_interrupt(unsigned int index) __m1_pmu_enable_counter_interrupt(index, false); } -static void m1_pmu_configure_counter(unsigned int index, u8 event, - bool user, bool kernel) +static void __m1_pmu_configure_event_filter(unsigned int index, bool user, + bool kernel) { - u64 val, user_bit, kernel_bit; - int shift; + u64 clear, set, user_bit, kernel_bit; switch (index) { case 0 ... 7: @@ -346,19 +345,24 @@ static void m1_pmu_configure_counter(unsigned int index, u8 event, BUG(); } - val = read_sysreg_s(SYS_IMP_APL_PMCR1_EL1); - + clear = set = 0; if (user) - val |= user_bit; + set |= user_bit; else - val &= ~user_bit; + clear |= user_bit; if (kernel) - val |= kernel_bit; + set |= kernel_bit; else - val &= ~kernel_bit; + clear |= kernel_bit; - write_sysreg_s(val, SYS_IMP_APL_PMCR1_EL1); + sysreg_clear_set_s(SYS_IMP_APL_PMCR1_EL1, clear, set); +} + +static void __m1_pmu_configure_eventsel(unsigned int index, u8 event) +{ + u64 clear = 0, set = 0; + int shift; /* * Counters 0 and 1 have fixed events. For anything else, @@ -371,21 +375,29 @@ static void m1_pmu_configure_counter(unsigned int index, u8 event, break; case 2 ... 5: shift = (index - 2) * 8; - val = read_sysreg_s(SYS_IMP_APL_PMESR0_EL1); - val &= ~((u64)0xff << shift); - val |= (u64)event << shift; - write_sysreg_s(val, SYS_IMP_APL_PMESR0_EL1); + clear |= (u64)0xff << shift; + set |= (u64)event << shift; + sysreg_clear_set_s(SYS_IMP_APL_PMESR0_EL1, clear, set); break; case 6 ... 9: shift = (index - 6) * 8; - val = read_sysreg_s(SYS_IMP_APL_PMESR1_EL1); - val &= ~((u64)0xff << shift); - val |= (u64)event << shift; - write_sysreg_s(val, SYS_IMP_APL_PMESR1_EL1); + clear |= (u64)0xff << shift; + set |= (u64)event << shift; + sysreg_clear_set_s(SYS_IMP_APL_PMESR1_EL1, clear, set); break; } } +static void m1_pmu_configure_counter(unsigned int index, unsigned long config_base) +{ + bool kernel = config_base & M1_PMU_CFG_COUNT_KERNEL; + bool user = config_base & M1_PMU_CFG_COUNT_USER; + u8 evt = config_base & M1_PMU_CFG_EVENT; + + __m1_pmu_configure_event_filter(index, user, kernel); + __m1_pmu_configure_eventsel(index, evt); +} + /* arm_pmu backend */ static void m1_pmu_enable_event(struct perf_event *event) { @@ -400,7 +412,7 @@ static void m1_pmu_enable_event(struct perf_event *event) m1_pmu_disable_counter(event->hw.idx); isb(); - m1_pmu_configure_counter(event->hw.idx, evt, user, kernel); + m1_pmu_configure_counter(event->hw.idx, event->hw.config_base); m1_pmu_enable_counter(event->hw.idx); m1_pmu_enable_counter_interrupt(event->hw.idx); isb(); From 46573d944f00f440dc794fa87ebbdb0dd9dbf691 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:29 -0800 Subject: [PATCH 02/14] drivers/perf: apple_m1: Support host/guest event filtering The PMU appears to have a separate register for filtering 'guest' exception levels (i.e. EL1 and !ELIsInHost(EL0)) which has the same layout as PMCR1_EL1. Conveniently, there exists a VHE register alias (PMCR1_EL12) that can be used to configure it. Support guest events by programming the EL12 register with the intended guest kernel/userspace filters. Limit support for guest events to VHE (i.e. kernel running at EL2), as it avoids involving KVM to context switch PMU registers. VHE is the only supported mode on M* parts anyway, so this isn't an actual feature limitation. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-3-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/include/asm/apple_m1_pmu.h | 1 + drivers/perf/apple_m1_cpu_pmu.c | 20 ++++++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/apple_m1_pmu.h b/arch/arm64/include/asm/apple_m1_pmu.h index 99483b19b99fc..02e05d05851f7 100644 --- a/arch/arm64/include/asm/apple_m1_pmu.h +++ b/arch/arm64/include/asm/apple_m1_pmu.h @@ -37,6 +37,7 @@ #define PMCR0_PMI_ENABLE_8_9 GENMASK(45, 44) #define SYS_IMP_APL_PMCR1_EL1 sys_reg(3, 1, 15, 1, 0) +#define SYS_IMP_APL_PMCR1_EL12 sys_reg(3, 1, 15, 7, 2) #define PMCR1_COUNT_A64_EL0_0_7 GENMASK(15, 8) #define PMCR1_COUNT_A64_EL1_0_7 GENMASK(23, 16) #define PMCR1_COUNT_A64_EL0_8_9 GENMASK(41, 40) diff --git a/drivers/perf/apple_m1_cpu_pmu.c b/drivers/perf/apple_m1_cpu_pmu.c index cea80afd12537..d6d4ff6da8626 100644 --- a/drivers/perf/apple_m1_cpu_pmu.c +++ b/drivers/perf/apple_m1_cpu_pmu.c @@ -120,6 +120,8 @@ enum m1_pmu_events { */ M1_PMU_CFG_COUNT_USER = BIT(8), M1_PMU_CFG_COUNT_KERNEL = BIT(9), + M1_PMU_CFG_COUNT_HOST = BIT(10), + M1_PMU_CFG_COUNT_GUEST = BIT(11), }; /* @@ -328,7 +330,7 @@ static void m1_pmu_disable_counter_interrupt(unsigned int index) } static void __m1_pmu_configure_event_filter(unsigned int index, bool user, - bool kernel) + bool kernel, bool host) { u64 clear, set, user_bit, kernel_bit; @@ -356,7 +358,10 @@ static void __m1_pmu_configure_event_filter(unsigned int index, bool user, else clear |= kernel_bit; - sysreg_clear_set_s(SYS_IMP_APL_PMCR1_EL1, clear, set); + if (host) + sysreg_clear_set_s(SYS_IMP_APL_PMCR1_EL1, clear, set); + else if (is_kernel_in_hyp_mode()) + sysreg_clear_set_s(SYS_IMP_APL_PMCR1_EL12, clear, set); } static void __m1_pmu_configure_eventsel(unsigned int index, u8 event) @@ -391,10 +396,13 @@ static void __m1_pmu_configure_eventsel(unsigned int index, u8 event) static void m1_pmu_configure_counter(unsigned int index, unsigned long config_base) { bool kernel = config_base & M1_PMU_CFG_COUNT_KERNEL; + bool guest = config_base & M1_PMU_CFG_COUNT_GUEST; + bool host = config_base & M1_PMU_CFG_COUNT_HOST; bool user = config_base & M1_PMU_CFG_COUNT_USER; u8 evt = config_base & M1_PMU_CFG_EVENT; - __m1_pmu_configure_event_filter(index, user, kernel); + __m1_pmu_configure_event_filter(index, user && host, kernel && host, true); + __m1_pmu_configure_event_filter(index, user && guest, kernel && guest, false); __m1_pmu_configure_eventsel(index, evt); } @@ -570,7 +578,7 @@ static int m1_pmu_set_event_filter(struct hw_perf_event *event, { unsigned long config_base = 0; - if (!attr->exclude_guest) { + if (!attr->exclude_guest && !is_kernel_in_hyp_mode()) { pr_debug("ARM performance counters do not support mode exclusion\n"); return -EOPNOTSUPP; } @@ -578,6 +586,10 @@ static int m1_pmu_set_event_filter(struct hw_perf_event *event, config_base |= M1_PMU_CFG_COUNT_KERNEL; if (!attr->exclude_user) config_base |= M1_PMU_CFG_COUNT_USER; + if (!attr->exclude_host) + config_base |= M1_PMU_CFG_COUNT_HOST; + if (!attr->exclude_guest) + config_base |= M1_PMU_CFG_COUNT_GUEST; event->config_base = config_base; From 93b01528586b693a3ab31ed7be92b2347a9416ca Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:30 -0800 Subject: [PATCH 03/14] KVM: arm64: Compute PMCEID from arm_pmu's event bitmaps The PMUv3 driver populates a couple of bitmaps with the values of PMCEID{0,1}, from which the guest's PMCEID{0,1} can be derived. This is particularly convenient when virtualizing PMUv3 on IMP DEF hardware, as reading the nonexistent PMCEID registers leads to a rather unpleasant UNDEF. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-4-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 47 ++++++++++++++++++++++++++++++--------- 1 file changed, 36 insertions(+), 11 deletions(-) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 6c5950b9ceac8..104672a0c5a21 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -842,8 +842,42 @@ static struct arm_pmu *kvm_pmu_probe_armpmu(void) return pmu; } +static u64 __compute_pmceid(struct arm_pmu *pmu, bool pmceid1) +{ + u32 hi[2], lo[2]; + + bitmap_to_arr32(lo, pmu->pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); + bitmap_to_arr32(hi, pmu->pmceid_ext_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); + + return ((u64)hi[pmceid1] << 32) | lo[pmceid1]; +} + +static u64 compute_pmceid0(struct arm_pmu *pmu) +{ + u64 val = __compute_pmceid(pmu, 0); + + /* always support CHAIN */ + val |= BIT(ARMV8_PMUV3_PERFCTR_CHAIN); + return val; +} + +static u64 compute_pmceid1(struct arm_pmu *pmu) +{ + u64 val = __compute_pmceid(pmu, 1); + + /* + * Don't advertise STALL_SLOT*, as PMMIR_EL0 is handled + * as RAZ + */ + val &= ~(BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32) | + BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_FRONTEND - 32) | + BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_BACKEND - 32)); + return val; +} + u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1) { + struct arm_pmu *cpu_pmu = vcpu->kvm->arch.arm_pmu; unsigned long *bmap = vcpu->kvm->arch.pmu_filter; u64 val, mask = 0; int base, i, nr_events; @@ -852,19 +886,10 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1) return 0; if (!pmceid1) { - val = read_sysreg(pmceid0_el0); - /* always support CHAIN */ - val |= BIT(ARMV8_PMUV3_PERFCTR_CHAIN); + val = compute_pmceid0(cpu_pmu); base = 0; } else { - val = read_sysreg(pmceid1_el0); - /* - * Don't advertise STALL_SLOT*, as PMMIR_EL0 is handled - * as RAZ - */ - val &= ~(BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32) | - BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_FRONTEND - 32) | - BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT_BACKEND - 32)); + val = compute_pmceid1(cpu_pmu); base = 32; } From ed335722b4571c438c008fc96bf86b9d4705a60f Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:31 -0800 Subject: [PATCH 04/14] KVM: arm64: Always support SW_INCR PMU event Support for SW_INCR is unconditional, as KVM traps accesses to PMSWINC_EL0 and emulates the intended event increment. While it is expected that ~all PMUv3 implementations already advertise this event, non-PMUv3 hardware may not. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-5-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 104672a0c5a21..62349b670cf92 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -856,6 +856,8 @@ static u64 compute_pmceid0(struct arm_pmu *pmu) { u64 val = __compute_pmceid(pmu, 0); + /* always support SW_INCR */ + val |= BIT(ARMV8_PMUV3_PERFCTR_SW_INCR); /* always support CHAIN */ val |= BIT(ARMV8_PMUV3_PERFCTR_CHAIN); return val; From 6f34024d185e2fa6636c660431c4595a6529328d Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:32 -0800 Subject: [PATCH 05/14] KVM: arm64: Use a cpucap to determine if system supports FEAT_PMUv3 KVM is about to learn some new tricks to virtualize PMUv3 on IMPDEF hardware. As part of that, we now need to differentiate host support from guest support for PMUv3. Add a cpucap to determine if an architectural PMUv3 is present to guard host usage of PMUv3 controls. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-6-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/include/asm/cpucaps.h | 2 ++ arch/arm64/include/asm/cpufeature.h | 5 +++++ arch/arm64/kernel/cpufeature.c | 30 +++++++++++++++++++++++++ arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ++-- arch/arm64/kvm/pmu.c | 10 ++++----- arch/arm64/tools/cpucaps | 1 + include/kvm/arm_pmu.h | 2 +- 7 files changed, 46 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 0b5ca6e0eb093..9d769291a3067 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -71,6 +71,8 @@ cpucap_is_possible(const unsigned int cap) * KVM MPAM support doesn't rely on the host kernel supporting MPAM. */ return true; + case ARM64_HAS_PMUV3: + return IS_ENABLED(CONFIG_HW_PERF_EVENTS); } return true; diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index e0e4478f5fb52..0eff048848b84 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -866,6 +866,11 @@ static __always_inline bool system_supports_mpam_hcr(void) return alternative_has_cap_unlikely(ARM64_MPAM_HCR); } +static inline bool system_supports_pmuv3(void) +{ + return cpus_have_final_cap(ARM64_HAS_PMUV3); +} + int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); bool try_emulate_mrs(struct pt_regs *regs, u32 isn); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index d561cf3b8ac7b..adb26697d908c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1898,6 +1898,28 @@ static bool has_lpa2(const struct arm64_cpu_capabilities *entry, int scope) } #endif +#ifdef CONFIG_HW_PERF_EVENTS +static bool has_pmuv3(const struct arm64_cpu_capabilities *entry, int scope) +{ + u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); + unsigned int pmuver; + + /* + * PMUVer follows the standard ID scheme for an unsigned field with the + * exception of 0xF (IMP_DEF) which is treated specially and implies + * FEAT_PMUv3 is not implemented. + * + * See DDI0487L.a D24.1.3.2 for more details. + */ + pmuver = cpuid_feature_extract_unsigned_field(dfr0, + ID_AA64DFR0_EL1_PMUVer_SHIFT); + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) + return false; + + return pmuver >= ID_AA64DFR0_EL1_PMUVer_IMP; +} +#endif + #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 #define KPTI_NG_TEMP_VA (-(1UL << PMD_SHIFT)) @@ -2998,6 +3020,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64PFR1_EL1, GCS, IMP) }, +#endif +#ifdef CONFIG_HW_PERF_EVENTS + { + .desc = "PMUv3", + .capability = ARM64_HAS_PMUV3, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_pmuv3, + }, #endif {}, }; diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 23bbe28eaaf95..b741ea6aefa58 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -244,7 +244,7 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu) * counter, which could make a PMXEVCNTR_EL0 access UNDEF at * EL1 instead of being trapped to EL2. */ - if (kvm_arm_support_pmu_v3()) { + if (system_supports_pmuv3()) { struct kvm_cpu_context *hctxt; write_sysreg(0, pmselr_el0); @@ -281,7 +281,7 @@ static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu) write_sysreg(*host_data_ptr(host_debug_state.mdcr_el2), mdcr_el2); write_sysreg(0, hstr_el2); - if (kvm_arm_support_pmu_v3()) { + if (system_supports_pmuv3()) { struct kvm_cpu_context *hctxt; hctxt = host_data_ptr(host_ctxt); diff --git a/arch/arm64/kvm/pmu.c b/arch/arm64/kvm/pmu.c index 0b3adf3e17b49..6b48a3d16d0d5 100644 --- a/arch/arm64/kvm/pmu.c +++ b/arch/arm64/kvm/pmu.c @@ -41,7 +41,7 @@ void kvm_set_pmu_events(u64 set, struct perf_event_attr *attr) { struct kvm_pmu_events *pmu = kvm_get_pmu_events(); - if (!kvm_arm_support_pmu_v3() || !kvm_pmu_switch_needed(attr)) + if (!system_supports_pmuv3() || !kvm_pmu_switch_needed(attr)) return; if (!attr->exclude_host) @@ -57,7 +57,7 @@ void kvm_clr_pmu_events(u64 clr) { struct kvm_pmu_events *pmu = kvm_get_pmu_events(); - if (!kvm_arm_support_pmu_v3()) + if (!system_supports_pmuv3()) return; pmu->events_host &= ~clr; @@ -133,7 +133,7 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) struct kvm_pmu_events *pmu; u64 events_guest, events_host; - if (!kvm_arm_support_pmu_v3() || !has_vhe()) + if (!system_supports_pmuv3() || !has_vhe()) return; preempt_disable(); @@ -154,7 +154,7 @@ void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) struct kvm_pmu_events *pmu; u64 events_guest, events_host; - if (!kvm_arm_support_pmu_v3() || !has_vhe()) + if (!system_supports_pmuv3() || !has_vhe()) return; pmu = kvm_get_pmu_events(); @@ -180,7 +180,7 @@ bool kvm_set_pmuserenr(u64 val) struct kvm_cpu_context *hctxt; struct kvm_vcpu *vcpu; - if (!kvm_arm_support_pmu_v3() || !has_vhe()) + if (!system_supports_pmuv3() || !has_vhe()) return false; vcpu = kvm_get_running_vcpu(); diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 1e65f2fb45bd1..ee4316cb36905 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -45,6 +45,7 @@ HAS_LSE_ATOMICS HAS_MOPS HAS_NESTED_VIRT HAS_PAN +HAS_PMUV3 HAS_S1PIE HAS_S1POE HAS_RAS_EXTN diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 147bd3ee4f7ba..3a8edd78240f7 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -86,7 +86,7 @@ void kvm_vcpu_pmu_resync_el0(void); */ #define kvm_pmu_update_vcpu_events(vcpu) \ do { \ - if (!has_vhe() && kvm_arm_support_pmu_v3()) \ + if (!has_vhe() && system_supports_pmuv3()) \ vcpu->arch.pmu.events = *kvm_get_pmu_events(); \ } while (0) From a38b67d1518331a4147c52c4fa563846ea0969f9 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:33 -0800 Subject: [PATCH 06/14] KVM: arm64: Drop kvm_arm_pmu_available static key With the PMUv3 cpucap, kvm_arm_pmu_available is no longer used in the hot path of guest entry/exit. On top of that, guest support for PMUv3 may not correlate with host support for the feature, e.g. on IMPDEF hardware. Throw out the static key and just inspect the list of PMUs to determine if PMUv3 is supported for KVM guests. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-7-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kernel/image-vars.h | 5 ----- arch/arm64/kvm/arm.c | 4 ++-- arch/arm64/kvm/pmu-emul.c | 11 ++++++----- include/kvm/arm_pmu.h | 10 ++-------- 4 files changed, 10 insertions(+), 20 deletions(-) diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index ef3a69cc398e5..e705c64138ce3 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -112,11 +112,6 @@ KVM_NVHE_ALIAS(broken_cntvoff_key); KVM_NVHE_ALIAS(__start___kvm_ex_table); KVM_NVHE_ALIAS(__stop___kvm_ex_table); -/* PMU available static key */ -#ifdef CONFIG_HW_PERF_EVENTS -KVM_NVHE_ALIAS(kvm_arm_pmu_available); -#endif - /* Position-independent library routines */ KVM_NVHE_ALIAS_HYP(clear_page, __pi_clear_page); KVM_NVHE_ALIAS_HYP(copy_page, __pi_copy_page); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index b8e55a441282f..dc27d4eb503a4 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -366,7 +366,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) r = get_num_wrps(); break; case KVM_CAP_ARM_PMU_V3: - r = kvm_arm_support_pmu_v3(); + r = kvm_supports_guest_pmuv3(); break; case KVM_CAP_ARM_INJECT_SERROR_ESR: r = cpus_have_final_cap(ARM64_HAS_RAS_EXTN); @@ -1388,7 +1388,7 @@ static unsigned long system_supported_vcpu_features(void) if (!cpus_have_final_cap(ARM64_HAS_32BIT_EL1)) clear_bit(KVM_ARM_VCPU_EL1_32BIT, &features); - if (!kvm_arm_support_pmu_v3()) + if (!kvm_supports_guest_pmuv3()) clear_bit(KVM_ARM_VCPU_PMU_V3, &features); if (!system_supports_sve()) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 62349b670cf92..120f48136a0f3 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -17,8 +17,6 @@ #define PERF_ATTR_CFG1_COUNTER_64BIT BIT(0) -DEFINE_STATIC_KEY_FALSE(kvm_arm_pmu_available); - static LIST_HEAD(arm_pmus); static DEFINE_MUTEX(arm_pmus_lock); @@ -26,6 +24,12 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc); static void kvm_pmu_release_perf_event(struct kvm_pmc *pmc); static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc); +bool kvm_supports_guest_pmuv3(void) +{ + guard(mutex)(&arm_pmus_lock); + return !list_empty(&arm_pmus); +} + static struct kvm_vcpu *kvm_pmc_to_vcpu(const struct kvm_pmc *pmc) { return container_of(pmc, struct kvm_vcpu, arch.pmu.pmc[pmc->idx]); @@ -795,9 +799,6 @@ void kvm_host_pmu_init(struct arm_pmu *pmu) entry->arm_pmu = pmu; list_add_tail(&entry->entry, &arm_pmus); - if (list_is_singular(&arm_pmus)) - static_branch_enable(&kvm_arm_pmu_available); - out_unlock: mutex_unlock(&arm_pmus_lock); } diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 3a8edd78240f7..58fc7f932b3fc 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -37,13 +37,7 @@ struct arm_pmu_entry { struct arm_pmu *arm_pmu; }; -DECLARE_STATIC_KEY_FALSE(kvm_arm_pmu_available); - -static __always_inline bool kvm_arm_support_pmu_v3(void) -{ - return static_branch_likely(&kvm_arm_pmu_available); -} - +bool kvm_supports_guest_pmuv3(void); #define kvm_arm_pmu_irq_initialized(v) ((v)->arch.pmu.irq_num >= VGIC_NR_SGIS) u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx); void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val); @@ -102,7 +96,7 @@ void kvm_pmu_nested_transition(struct kvm_vcpu *vcpu); struct kvm_pmu { }; -static inline bool kvm_arm_support_pmu_v3(void) +static inline bool kvm_supports_guest_pmuv3(void) { return false; } From 3d6d9172128ef6219b737d0b05a225f37b0f3ab6 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:34 -0800 Subject: [PATCH 07/14] KVM: arm64: Use guard() to cleanup usage of arm_pmus_lock Get rid of some goto label patterns by using guard() to drop the arm_pmus_lock when returning from a function. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-8-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 120f48136a0f3..fee3d0003d544 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -790,26 +790,23 @@ void kvm_host_pmu_init(struct arm_pmu *pmu) if (!pmuv3_implemented(kvm_arm_pmu_get_pmuver_limit())) return; - mutex_lock(&arm_pmus_lock); + guard(mutex)(&arm_pmus_lock); entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) - goto out_unlock; + return; entry->arm_pmu = pmu; list_add_tail(&entry->entry, &arm_pmus); - -out_unlock: - mutex_unlock(&arm_pmus_lock); } static struct arm_pmu *kvm_pmu_probe_armpmu(void) { - struct arm_pmu *tmp, *pmu = NULL; struct arm_pmu_entry *entry; + struct arm_pmu *pmu; int cpu; - mutex_lock(&arm_pmus_lock); + guard(mutex)(&arm_pmus_lock); /* * It is safe to use a stale cpu to iterate the list of PMUs so long as @@ -830,17 +827,13 @@ static struct arm_pmu *kvm_pmu_probe_armpmu(void) */ cpu = raw_smp_processor_id(); list_for_each_entry(entry, &arm_pmus, entry) { - tmp = entry->arm_pmu; + pmu = entry->arm_pmu; - if (cpumask_test_cpu(cpu, &tmp->supported_cpus)) { - pmu = tmp; - break; - } + if (cpumask_test_cpu(cpu, &pmu->supported_cpus)) + return pmu; } - mutex_unlock(&arm_pmus_lock); - - return pmu; + return NULL; } static u64 __compute_pmceid(struct arm_pmu *pmu, bool pmceid1) From 56290316a443709957f958e4e40bc93e0213bcc3 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:35 -0800 Subject: [PATCH 08/14] KVM: arm64: Move PMUVer filtering into KVM code The supported guest PMU version on a particular platform is ultimately a KVM decision. Move PMUVer filtering into KVM code. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-9-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/include/asm/cpufeature.h | 23 ----------------------- arch/arm64/kvm/pmu-emul.c | 15 +++++++++------ 2 files changed, 9 insertions(+), 29 deletions(-) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 0eff048848b84..c4326f1cb9176 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -525,29 +525,6 @@ cpuid_feature_extract_unsigned_field(u64 features, int field) return cpuid_feature_extract_unsigned_field_width(features, field, 4); } -/* - * Fields that identify the version of the Performance Monitors Extension do - * not follow the standard ID scheme. See ARM DDI 0487E.a page D13-2825, - * "Alternative ID scheme used for the Performance Monitors Extension version". - */ -static inline u64 __attribute_const__ -cpuid_feature_cap_perfmon_field(u64 features, int field, u64 cap) -{ - u64 val = cpuid_feature_extract_unsigned_field(features, field); - u64 mask = GENMASK_ULL(field + 3, field); - - /* Treat IMPLEMENTATION DEFINED functionality as unimplemented */ - if (val == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) - val = 0; - - if (val > cap) { - features &= ~mask; - features |= (cap << field) & mask; - } - - return features; -} - static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp) { return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift); diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index fee3d0003d544..0a2023aabe184 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -1226,13 +1226,16 @@ int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr) u8 kvm_arm_pmu_get_pmuver_limit(void) { - u64 tmp; + unsigned int pmuver; - tmp = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); - tmp = cpuid_feature_cap_perfmon_field(tmp, - ID_AA64DFR0_EL1_PMUVer_SHIFT, - ID_AA64DFR0_EL1_PMUVer_V3P5); - return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), tmp); + pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, + read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1)); + + /* Treat IMPLEMENTATION DEFINED functionality as unimplemented */ + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) + return 0; + + return min(pmuver, ID_AA64DFR0_EL1_PMUVer_V3P5); } /** From 2c433f70dccc1af6922931404bfe23d215bdfff0 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:36 -0800 Subject: [PATCH 09/14] KVM: arm64: Compute synthetic sysreg ESR for Apple PMUv3 traps Apple M* CPUs provide an IMPDEF trap for PMUv3 sysregs, where ESR_EL2.EC is a reserved value (0x3F) and a sysreg-like ISS is reported in AFSR1_EL2. Compute a synthetic ESR for these PMUv3 traps, giving the illusion of something architectural to the rest of KVM. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-10-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/vhe/switch.c | 22 ++++++++++++++++++++++ arch/arm64/tools/cpucaps | 1 + 2 files changed, 23 insertions(+) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 647737d6e8d0b..731a0378ed132 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -527,6 +527,25 @@ static bool kvm_hyp_handle_sysreg_vhe(struct kvm_vcpu *vcpu, u64 *exit_code) return kvm_hyp_handle_sysreg(vcpu, exit_code); } +static bool kvm_hyp_handle_impdef(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + u64 iss; + + if (!cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS)) + return false; + + /* + * Compute a synthetic ESR for a sysreg trap. Conveniently, AFSR1_EL2 + * is populated with a correct ISS for a sysreg trap. These fruity + * parts are 64bit only, so unconditionally set IL. + */ + iss = ESR_ELx_ISS(read_sysreg_s(SYS_AFSR1_EL2)); + vcpu->arch.fault.esr_el2 = FIELD_PREP(ESR_ELx_EC_MASK, ESR_ELx_EC_SYS64) | + FIELD_PREP(ESR_ELx_ISS_MASK, iss) | + ESR_ELx_IL; + return false; +} + static const exit_handler_fn hyp_exit_handlers[] = { [0 ... ESR_ELx_EC_MAX] = NULL, [ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32, @@ -538,6 +557,9 @@ static const exit_handler_fn hyp_exit_handlers[] = { [ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low, [ESR_ELx_EC_ERET] = kvm_hyp_handle_eret, [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, + + /* Apple shenanigans */ + [0x3F] = kvm_hyp_handle_impdef, }; static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index ee4316cb36905..772c1b008e437 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -105,6 +105,7 @@ WORKAROUND_CAVIUM_TX2_219_TVM WORKAROUND_CLEAN_CACHE WORKAROUND_DEVICE_LOAD_ACQUIRE WORKAROUND_NVIDIA_CARMEL_CNP +WORKAROUND_PMUV3_IMPDEF_TRAPS WORKAROUND_QCOM_FALKOR_E1003 WORKAROUND_QCOM_ORYON_CNTVOFF WORKAROUND_REPEAT_TLBI From bed9b8ec8c71135c59004d12658d8affe232f27e Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:37 -0800 Subject: [PATCH 10/14] KVM: arm64: Advertise PMUv3 if IMPDEF traps are present Advertise a baseline PMUv3 implementation when running on hardware with IMPDEF traps of the PMUv3 sysregs. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-11-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 0a2023aabe184..38d9490c17fd9 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -1231,7 +1231,17 @@ u8 kvm_arm_pmu_get_pmuver_limit(void) pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1)); - /* Treat IMPLEMENTATION DEFINED functionality as unimplemented */ + /* + * Spoof a barebones PMUv3 implementation if the system supports IMPDEF + * traps of the PMUv3 sysregs + */ + if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS)) + return ID_AA64DFR0_EL1_PMUVer_IMP; + + /* + * Otherwise, treat IMPLEMENTATION DEFINED functionality as + * unimplemented + */ if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF) return 0; From 1e7dcbfa4b7cddfbe1cde6067d135f5452692256 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:38 -0800 Subject: [PATCH 11/14] KVM: arm64: Remap PMUv3 events onto hardware Map PMUv3 event IDs onto hardware, if the driver exposes such a helper. This is expected to be quite rare, and only useful for non-PMUv3 hardware. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-12-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 25 ++++++++++++++++++++++++- include/linux/perf/arm_pmu.h | 4 ++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 38d9490c17fd9..5f4e9be8aa8bf 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -677,6 +677,20 @@ static bool kvm_pmc_counts_at_el2(struct kvm_pmc *pmc) return kvm_pmc_read_evtreg(pmc) & ARMV8_PMU_INCLUDE_EL2; } +static int kvm_map_pmu_event(struct kvm *kvm, unsigned int eventsel) +{ + struct arm_pmu *pmu = kvm->arch.arm_pmu; + + /* + * The CPU PMU likely isn't PMUv3; let the driver provide a mapping + * for the guest's PMUv3 event ID. + */ + if (unlikely(pmu->map_pmuv3_event)) + return pmu->map_pmuv3_event(eventsel); + + return eventsel; +} + /** * kvm_pmu_create_perf_event - create a perf event for a counter * @pmc: Counter context @@ -687,7 +701,8 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu; struct perf_event *event; struct perf_event_attr attr; - u64 eventsel, evtreg; + int eventsel; + u64 evtreg; evtreg = kvm_pmc_read_evtreg(pmc); @@ -713,6 +728,14 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) !test_bit(eventsel, vcpu->kvm->arch.pmu_filter)) return; + /* + * Don't create an event if we're running on hardware that requires + * PMUv3 event translation and we couldn't find a valid mapping. + */ + eventsel = kvm_map_pmu_event(vcpu->kvm, eventsel); + if (eventsel < 0) + return; + memset(&attr, 0, sizeof(struct perf_event_attr)); attr.type = arm_pmu->pmu.type; attr.size = sizeof(attr); diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 4b5b83677e3f2..7ce6dea5bfa9f 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -100,6 +100,10 @@ struct arm_pmu { void (*stop)(struct arm_pmu *); void (*reset)(void *); int (*map_event)(struct perf_event *event); + /* + * Called by KVM to map the PMUv3 event space onto non-PMUv3 hardware. + */ + int (*map_pmuv3_event)(unsigned int eventsel); DECLARE_BITMAP(cntr_mask, ARMPMU_MAX_HWEVENTS); bool secure_access; /* 32-bit ARM only */ #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 From 2d00cab849be5e4c1b2ba82d4fdcfa0af48c340f Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:26:39 -0800 Subject: [PATCH 12/14] drivers/perf: apple_m1: Provide helper for mapping PMUv3 events Apple M* parts carry some IMP DEF traps for guest accesses to PMUv3 registers, even though the underlying hardware doesn't implement PMUv3. This means it is possible to virtualize PMUv3 for KVM guests. Add a helper for mapping common PMUv3 event IDs onto hardware event IDs, keeping the implementation-specific crud in the PMU driver rather than KVM proper. Populate the pmceid_bitmap based on the supported events so KVM can provide synthetic PMCEID* values to the guest. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-13-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- drivers/perf/apple_m1_cpu_pmu.c | 35 +++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/perf/apple_m1_cpu_pmu.c b/drivers/perf/apple_m1_cpu_pmu.c index d6d4ff6da8626..6be703619a977 100644 --- a/drivers/perf/apple_m1_cpu_pmu.c +++ b/drivers/perf/apple_m1_cpu_pmu.c @@ -12,6 +12,7 @@ #include #include +#include #include #include @@ -174,6 +175,17 @@ static const unsigned m1_pmu_perf_map[PERF_COUNT_HW_MAX] = { [PERF_COUNT_HW_BRANCH_MISSES] = M1_PMU_PERFCTR_BRANCH_MISPRED_NONSPEC, }; +#define M1_PMUV3_EVENT_MAP(pmuv3_event, m1_event) \ + [ARMV8_PMUV3_PERFCTR_##pmuv3_event] = M1_PMU_PERFCTR_##m1_event + +static const u16 m1_pmu_pmceid_map[ARMV8_PMUV3_MAX_COMMON_EVENTS] = { + [0 ... ARMV8_PMUV3_MAX_COMMON_EVENTS - 1] = HW_OP_UNSUPPORTED, + M1_PMUV3_EVENT_MAP(INST_RETIRED, INST_ALL), + M1_PMUV3_EVENT_MAP(CPU_CYCLES, CORE_ACTIVE_CYCLE), + M1_PMUV3_EVENT_MAP(BR_RETIRED, INST_BRANCH), + M1_PMUV3_EVENT_MAP(BR_MIS_PRED_RETIRED, BRANCH_MISPRED_NONSPEC), +}; + /* sysfs definitions */ static ssize_t m1_pmu_events_sysfs_show(struct device *dev, struct device_attribute *attr, @@ -558,6 +570,26 @@ static int m2_pmu_map_event(struct perf_event *event) return armpmu_map_event(event, &m1_pmu_perf_map, NULL, M1_PMU_CFG_EVENT); } +static int m1_pmu_map_pmuv3_event(unsigned int eventsel) +{ + u16 m1_event = HW_OP_UNSUPPORTED; + + if (eventsel < ARMV8_PMUV3_MAX_COMMON_EVENTS) + m1_event = m1_pmu_pmceid_map[eventsel]; + + return m1_event == HW_OP_UNSUPPORTED ? -EOPNOTSUPP : m1_event; +} + +static void m1_pmu_init_pmceid(struct arm_pmu *pmu) +{ + unsigned int event; + + for (event = 0; event < ARMV8_PMUV3_MAX_COMMON_EVENTS; event++) { + if (m1_pmu_map_pmuv3_event(event) >= 0) + set_bit(event, pmu->pmceid_bitmap); + } +} + static void m1_pmu_reset(void *info) { int i; @@ -618,6 +650,9 @@ static int m1_pmu_init(struct arm_pmu *cpu_pmu, u32 flags) cpu_pmu->reset = m1_pmu_reset; cpu_pmu->set_event_filter = m1_pmu_set_event_filter; + cpu_pmu->map_pmuv3_event = m1_pmu_map_pmuv3_event; + m1_pmu_init_pmceid(cpu_pmu); + bitmap_set(cpu_pmu->cntr_mask, 0, M1_PMU_NR_COUNTERS); cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group; cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_FORMATS] = &m1_pmu_format_attr_group; From 1b92e65f5006da55c8779b86f052855a49ecdd97 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:30:21 -0800 Subject: [PATCH 13/14] KVM: arm64: Provide 1 event counter on IMPDEF hardware PMUv3 requires that all programmable event counters are capable of counting any event. The Apple M* PMU is quite a bit different, and events have affinities for particular PMCs. Expose 1 event counter on IMPDEF hardware, allowing the guest to do something useful with its PMU while also upholding the requirements of the architecture. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305203021.428366-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/pmu-emul.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 5f4e9be8aa8bf..51fb47e0bf893 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -1038,6 +1038,13 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm) { struct arm_pmu *arm_pmu = kvm->arch.arm_pmu; + /* + * PMUv3 requires that all event counters are capable of counting any + * event, though the same may not be true of non-PMUv3 hardware. + */ + if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS)) + return 1; + /* * The arm_pmu->cntr_mask considers the fixed counter(s) as well. * Ignore those and return only the general-purpose counters. From e1231aacb065b2594d6f4833896aedc142fbd1d6 Mon Sep 17 00:00:00 2001 From: Oliver Upton Date: Wed, 5 Mar 2025 12:30:40 -0800 Subject: [PATCH 14/14] arm64: Enable IMP DEF PMUv3 traps on Apple M* Apple M1 and M2 CPUs support IMPDEF traps of the PMUv3 sysregs, allowing a hypervisor to virtualize an architectural PMU for a VM. Flip the appropriate bit in HACR_EL2 on supporting hardware. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305203040.428448-1-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kernel/cpu_errata.c | 44 ++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 7ce5558628951..a1e16b156fab3 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -194,6 +194,43 @@ has_neoverse_n1_erratum_1542419(const struct arm64_cpu_capabilities *entry, return is_midr_in_range(midr, &range) && has_dic; } +static const struct midr_range impdef_pmuv3_cpus[] = { + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM), + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM), + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_PRO), + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_PRO), + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_ICESTORM_MAX), + MIDR_ALL_VERSIONS(MIDR_APPLE_M1_FIRESTORM_MAX), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD_PRO), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE_PRO), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_BLIZZARD_MAX), + MIDR_ALL_VERSIONS(MIDR_APPLE_M2_AVALANCHE_MAX), + {}, +}; + +static bool has_impdef_pmuv3(const struct arm64_cpu_capabilities *entry, int scope) +{ + u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); + unsigned int pmuver; + + if (!is_kernel_in_hyp_mode()) + return false; + + pmuver = cpuid_feature_extract_unsigned_field(dfr0, + ID_AA64DFR0_EL1_PMUVer_SHIFT); + if (pmuver != ID_AA64DFR0_EL1_PMUVer_IMP_DEF) + return false; + + return is_midr_in_range_list(read_cpuid_id(), impdef_pmuv3_cpus); +} + +static void cpu_enable_impdef_pmuv3_traps(const struct arm64_cpu_capabilities *__unused) +{ + sysreg_clear_set_s(SYS_HACR_EL2, 0, BIT(56)); +} + #ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI static const struct arm64_cpu_capabilities arm64_repeat_tlbi_list[] = { #ifdef CONFIG_QCOM_FALKOR_ERRATUM_1009 @@ -794,6 +831,13 @@ const struct arm64_cpu_capabilities arm64_errata[] = { {} })), }, + { + .desc = "Apple IMPDEF PMUv3 Traps", + .capability = ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS, + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, + .matches = has_impdef_pmuv3, + .cpu_enable = cpu_enable_impdef_pmuv3_traps, + }, { } };