Re: [PATCH v6 09/20] KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets

From: Jim Mattson
Date: Sat Nov 04 2023 - 09:24:00 EST

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In reply to: Sean Christopherson: "[PATCH v6 09/20] KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets"
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On Fri, Nov 3, 2023 at 5:02 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote:
>
> From: Jinrong Liang <cloudliang@xxxxxxxxxxx>
>
> By defining the PMU performance events and masks relevant for x86 in
> the new pmu.h and pmu.c, it becomes easier to reference them, minimizing
> potential errors in code that handles these values.
>
> Clean up pmu_event_filter_test.c by including pmu.h and removing
> unnecessary macros.
>
> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Jinrong Liang <cloudliang@xxxxxxxxxxx>
> [sean: drop PSEUDO_ARCH_REFERENCE_CYCLES]
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
> tools/testing/selftests/kvm/Makefile | 1 +
> tools/testing/selftests/kvm/include/pmu.h | 84 +++++++++++++++++++
> tools/testing/selftests/kvm/lib/pmu.c | 28 +++++++
> .../kvm/x86_64/pmu_event_filter_test.c | 32 ++-----
> 4 files changed, 122 insertions(+), 23 deletions(-)
> create mode 100644 tools/testing/selftests/kvm/include/pmu.h
> create mode 100644 tools/testing/selftests/kvm/lib/pmu.c
>
> diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
> index a5963ab9215b..44d8d022b023 100644
> --- a/tools/testing/selftests/kvm/Makefile
> +++ b/tools/testing/selftests/kvm/Makefile
> @@ -32,6 +32,7 @@ LIBKVM += lib/guest_modes.c
> LIBKVM += lib/io.c
> LIBKVM += lib/kvm_util.c
> LIBKVM += lib/memstress.c
> +LIBKVM += lib/pmu.c
> LIBKVM += lib/guest_sprintf.c
> LIBKVM += lib/rbtree.c
> LIBKVM += lib/sparsebit.c
> diff --git a/tools/testing/selftests/kvm/include/pmu.h b/tools/testing/selftests/kvm/include/pmu.h
> new file mode 100644
> index 000000000000..987602c62b51
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/include/pmu.h
> @@ -0,0 +1,84 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2023, Tencent, Inc.
> + */
> +#ifndef SELFTEST_KVM_PMU_H
> +#define SELFTEST_KVM_PMU_H
> +
> +#include <stdint.h>
> +
> +#define X86_PMC_IDX_MAX 64
> +#define INTEL_PMC_MAX_GENERIC 32

I think this is actually 15. Note that IA32_PMC0 through IA32_PMC7
have MSR indices from 0xc1 through 0xc8, and MSR 0xcf is
IA32_CORE_CAPABILITIES. At the very least, we have to handle
non-contiguous MSR indices if we ever go beyond IA32_PMC14.

> +#define KVM_PMU_EVENT_FILTER_MAX_EVENTS 300
> +
> +#define GP_COUNTER_NR_OFS_BIT 8
> +#define EVENT_LENGTH_OFS_BIT 24
> +
> +#define PMU_VERSION_MASK GENMASK_ULL(7, 0)
> +#define EVENT_LENGTH_MASK GENMASK_ULL(31, EVENT_LENGTH_OFS_BIT)
> +#define GP_COUNTER_NR_MASK GENMASK_ULL(15, GP_COUNTER_NR_OFS_BIT)
> +#define FIXED_COUNTER_NR_MASK GENMASK_ULL(4, 0)
> +
> +#define ARCH_PERFMON_EVENTSEL_EVENT GENMASK_ULL(7, 0)
> +#define ARCH_PERFMON_EVENTSEL_UMASK GENMASK_ULL(15, 8)
> +#define ARCH_PERFMON_EVENTSEL_USR BIT_ULL(16)
> +#define ARCH_PERFMON_EVENTSEL_OS BIT_ULL(17)
> +#define ARCH_PERFMON_EVENTSEL_EDGE BIT_ULL(18)
> +#define ARCH_PERFMON_EVENTSEL_PIN_CONTROL BIT_ULL(19)
> +#define ARCH_PERFMON_EVENTSEL_INT BIT_ULL(20)
> +#define ARCH_PERFMON_EVENTSEL_ANY BIT_ULL(21)
> +#define ARCH_PERFMON_EVENTSEL_ENABLE BIT_ULL(22)
> +#define ARCH_PERFMON_EVENTSEL_INV BIT_ULL(23)
> +#define ARCH_PERFMON_EVENTSEL_CMASK GENMASK_ULL(31, 24)
> +
> +#define PMC_MAX_FIXED 16
> +#define PMC_IDX_FIXED 32
> +
> +/* RDPMC offset for Fixed PMCs */
> +#define PMC_FIXED_RDPMC_BASE BIT_ULL(30)
> +#define PMC_FIXED_RDPMC_METRICS BIT_ULL(29)
> +
> +#define FIXED_BITS_MASK 0xFULL
> +#define FIXED_BITS_STRIDE 4
> +#define FIXED_0_KERNEL BIT_ULL(0)
> +#define FIXED_0_USER BIT_ULL(1)
> +#define FIXED_0_ANYTHREAD BIT_ULL(2)
> +#define FIXED_0_ENABLE_PMI BIT_ULL(3)
> +
> +#define fixed_bits_by_idx(_idx, _bits) \
> + ((_bits) << ((_idx) * FIXED_BITS_STRIDE))
> +
> +#define AMD64_NR_COUNTERS 4
> +#define AMD64_NR_COUNTERS_CORE 6
> +
> +#define PMU_CAP_FW_WRITES BIT_ULL(13)
> +#define PMU_CAP_LBR_FMT 0x3f
> +
> +enum intel_pmu_architectural_events {
> + /*
> + * The order of the architectural events matters as support for each
> + * event is enumerated via CPUID using the index of the event.
> + */
> + INTEL_ARCH_CPU_CYCLES,
> + INTEL_ARCH_INSTRUCTIONS_RETIRED,
> + INTEL_ARCH_REFERENCE_CYCLES,
> + INTEL_ARCH_LLC_REFERENCES,
> + INTEL_ARCH_LLC_MISSES,
> + INTEL_ARCH_BRANCHES_RETIRED,
> + INTEL_ARCH_BRANCHES_MISPREDICTED,
> + NR_INTEL_ARCH_EVENTS,
> +};
> +
> +enum amd_pmu_k7_events {
> + AMD_ZEN_CORE_CYCLES,
> + AMD_ZEN_INSTRUCTIONS,
> + AMD_ZEN_BRANCHES,
> + AMD_ZEN_BRANCH_MISSES,
> + NR_AMD_ARCH_EVENTS,
> +};
> +
> +extern const uint64_t intel_pmu_arch_events[];
> +extern const uint64_t amd_pmu_arch_events[];

AMD doesn't define *any* architectural events. Perhaps
amd_pmu_zen_events[], though who knows what Zen5 and beyond will
bring?

> +extern const int intel_pmu_fixed_pmc_events[];
> +
> +#endif /* SELFTEST_KVM_PMU_H */
> diff --git a/tools/testing/selftests/kvm/lib/pmu.c b/tools/testing/selftests/kvm/lib/pmu.c
> new file mode 100644
> index 000000000000..27a6c35f98a1
> --- /dev/null
> +++ b/tools/testing/selftests/kvm/lib/pmu.c
> @@ -0,0 +1,28 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2023, Tencent, Inc.
> + */
> +
> +#include <stdint.h>
> +
> +#include "pmu.h"
> +
> +/* Definitions for Architectural Performance Events */
> +#define ARCH_EVENT(select, umask) (((select) & 0xff) | ((umask) & 0xff) << 8)

There's nothing architectural about this. Perhaps RAW_EVENT() for
consistency with perf?

> +
> +const uint64_t intel_pmu_arch_events[] = {
> + [INTEL_ARCH_CPU_CYCLES] = ARCH_EVENT(0x3c, 0x0),
> + [INTEL_ARCH_INSTRUCTIONS_RETIRED] = ARCH_EVENT(0xc0, 0x0),
> + [INTEL_ARCH_REFERENCE_CYCLES] = ARCH_EVENT(0x3c, 0x1),
> + [INTEL_ARCH_LLC_REFERENCES] = ARCH_EVENT(0x2e, 0x4f),
> + [INTEL_ARCH_LLC_MISSES] = ARCH_EVENT(0x2e, 0x41),
> + [INTEL_ARCH_BRANCHES_RETIRED] = ARCH_EVENT(0xc4, 0x0),
> + [INTEL_ARCH_BRANCHES_MISPREDICTED] = ARCH_EVENT(0xc5, 0x0),

[INTEL_ARCH_TOPDOWN_SLOTS] = ARCH_EVENT(0xa4, 1),

> +};
> +
> +const uint64_t amd_pmu_arch_events[] = {
> + [AMD_ZEN_CORE_CYCLES] = ARCH_EVENT(0x76, 0x00),
> + [AMD_ZEN_INSTRUCTIONS] = ARCH_EVENT(0xc0, 0x00),
> + [AMD_ZEN_BRANCHES] = ARCH_EVENT(0xc2, 0x00),
> + [AMD_ZEN_BRANCH_MISSES] = ARCH_EVENT(0xc3, 0x00),
> +};
> diff --git a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> index 283cc55597a4..b6e4f57a8651 100644
> --- a/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/pmu_event_filter_test.c
> @@ -11,31 +11,18 @@
> */
>
> #define _GNU_SOURCE /* for program_invocation_short_name */
> -#include "test_util.h"
> +
> #include "kvm_util.h"
> +#include "pmu.h"
> #include "processor.h"
> -
> -/*
> - * In lieu of copying perf_event.h into tools...
> - */
> -#define ARCH_PERFMON_EVENTSEL_OS (1ULL << 17)
> -#define ARCH_PERFMON_EVENTSEL_ENABLE (1ULL << 22)
> -
> -/* End of stuff taken from perf_event.h. */
> -
> -/* Oddly, this isn't in perf_event.h. */
> -#define ARCH_PERFMON_BRANCHES_RETIRED 5
> +#include "test_util.h"
>
> #define NUM_BRANCHES 42
> -#define INTEL_PMC_IDX_FIXED 32
> -
> -/* Matches KVM_PMU_EVENT_FILTER_MAX_EVENTS in pmu.c */
> -#define MAX_FILTER_EVENTS 300
> #define MAX_TEST_EVENTS 10
>
> #define PMU_EVENT_FILTER_INVALID_ACTION (KVM_PMU_EVENT_DENY + 1)
> #define PMU_EVENT_FILTER_INVALID_FLAGS (KVM_PMU_EVENT_FLAGS_VALID_MASK << 1)
> -#define PMU_EVENT_FILTER_INVALID_NEVENTS (MAX_FILTER_EVENTS + 1)
> +#define PMU_EVENT_FILTER_INVALID_NEVENTS (KVM_PMU_EVENT_FILTER_MAX_EVENTS + 1)
>
> /*
> * This is how the event selector and unit mask are stored in an AMD
> @@ -63,7 +50,6 @@
>
> #define AMD_ZEN_BR_RETIRED EVENT(0xc2, 0)

Now AMD_ZEN_BRANCHES, above?

>
> -
> /*
> * "Retired instructions", from Processor Programming Reference
> * (PPR) for AMD Family 17h Model 01h, Revision B1 Processors,
> @@ -84,7 +70,7 @@ struct __kvm_pmu_event_filter {
> __u32 fixed_counter_bitmap;
> __u32 flags;
> __u32 pad[4];
> - __u64 events[MAX_FILTER_EVENTS];
> + __u64 events[KVM_PMU_EVENT_FILTER_MAX_EVENTS];
> };
>
> /*
> @@ -729,14 +715,14 @@ static void add_dummy_events(uint64_t *events, int nevents)
>
> static void test_masked_events(struct kvm_vcpu *vcpu)
> {
> - int nevents = MAX_FILTER_EVENTS - MAX_TEST_EVENTS;
> - uint64_t events[MAX_FILTER_EVENTS];
> + int nevents = KVM_PMU_EVENT_FILTER_MAX_EVENTS - MAX_TEST_EVENTS;
> + uint64_t events[KVM_PMU_EVENT_FILTER_MAX_EVENTS];
>
> /* Run the test cases against a sparse PMU event filter. */
> run_masked_events_tests(vcpu, events, 0);
>
> /* Run the test cases against a dense PMU event filter. */
> - add_dummy_events(events, MAX_FILTER_EVENTS);
> + add_dummy_events(events, KVM_PMU_EVENT_FILTER_MAX_EVENTS);
> run_masked_events_tests(vcpu, events, nevents);
> }
>
> @@ -818,7 +804,7 @@ static void intel_run_fixed_counter_guest_code(uint8_t fixed_ctr_idx)
> /* Only OS_EN bit is enabled for fixed counter[idx]. */
> wrmsr(MSR_CORE_PERF_FIXED_CTR_CTRL, BIT_ULL(4 * fixed_ctr_idx));
> wrmsr(MSR_CORE_PERF_GLOBAL_CTRL,
> - BIT_ULL(INTEL_PMC_IDX_FIXED + fixed_ctr_idx));
> + BIT_ULL(PMC_IDX_FIXED + fixed_ctr_idx));
> __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES}));
> wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0);
>
> --
> 2.42.0.869.gea05f2083d-goog
>

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In reply to: Sean Christopherson: "[PATCH v6 09/20] KVM: selftests: Add pmu.h and lib/pmu.c for common PMU assets"
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