From: Jinrong Liang cloudliang@tencent.com

Add fixed_counter_bitmap to the create_pmu_event_filter() to support the use of the same creator to control the use of guest fixed counters.

No functional change intended.

Signed-off-by: Jinrong Liang cloudliang@tencent.com --- .../kvm/x86_64/pmu_event_filter_test.c | 31 ++++++++++++------- 1 file changed, 19 insertions(+), 12 deletions(-)

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 c0521fc9e8f6..4e87eea6986b 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 @@ -192,19 +192,22 @@ static struct kvm_pmu_event_filter *alloc_pmu_event_filter(uint32_t nevents) return f; }

- static struct kvm_pmu_event_filter * create_pmu_event_filter(const uint64_t event_list[], uint32_t nevents, - uint32_t action, uint32_t flags) + uint32_t action, uint32_t flags, + uint32_t fixed_counter_bitmap) { struct kvm_pmu_event_filter *f; int i;

f = alloc_pmu_event_filter(nevents); f->action = action; + f->fixed_counter_bitmap = fixed_counter_bitmap; f->flags = flags; - for (i = 0; i < nevents; i++) - f->events[i] = event_list[i]; + if (f->nevents) { + for (i = 0; i < f->nevents; i++) + f->events[i] = event_list[i]; + }

return f; } @@ -213,7 +216,7 @@ static struct kvm_pmu_event_filter *event_filter(uint32_t action) { return create_pmu_event_filter(event_list, ARRAY_SIZE(event_list), - action, 0); + action, 0, 0); }

/* @@ -260,7 +263,7 @@ static void test_amd_deny_list(struct kvm_vcpu *vcpu) struct kvm_pmu_event_filter *f; uint64_t count;

- f = create_pmu_event_filter(&event, 1, KVM_PMU_EVENT_DENY, 0); + f = create_pmu_event_filter(&event, 1, KVM_PMU_EVENT_DENY, 0, 0); count = test_with_filter(vcpu, f);

free(f); @@ -544,7 +547,7 @@ static struct perf_counter run_masked_events_test(struct kvm_vcpu *vcpu,

f = create_pmu_event_filter(masked_events, nmasked_events, KVM_PMU_EVENT_ALLOW, - KVM_PMU_EVENT_FLAG_MASKED_EVENTS); + KVM_PMU_EVENT_FLAG_MASKED_EVENTS, 0); r.raw = test_with_filter(vcpu, f); free(f);

@@ -726,12 +729,14 @@ static void test_masked_events(struct kvm_vcpu *vcpu) }

static int run_filter_test(struct kvm_vcpu *vcpu, const uint64_t *events, - uint32_t nevents, uint32_t flags) + uint32_t nevents, uint32_t flags, uint32_t action, + uint32_t fixed_counter_bitmap) { struct kvm_pmu_event_filter *f; int r;

- f = create_pmu_event_filter(events, nevents, KVM_PMU_EVENT_ALLOW, flags); + f = create_pmu_event_filter(events, nevents, action, flags, + fixed_counter_bitmap); r = __vm_ioctl(vcpu->vm, KVM_SET_PMU_EVENT_FILTER, f); free(f);

@@ -747,14 +752,16 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu) * Unfortunately having invalid bits set in event data is expected to * pass when flags == 0 (bits other than eventsel+umask). */ - r = run_filter_test(vcpu, &e, 1, 0); + r = run_filter_test(vcpu, &e, 1, 0, KVM_PMU_EVENT_ALLOW, 0); TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing");

- r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS); + r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS, + KVM_PMU_EVENT_ALLOW, 0); TEST_ASSERT(r != 0, "Invalid PMU Event Filter is expected to fail");

e = KVM_PMU_ENCODE_MASKED_ENTRY(0xff, 0xff, 0xff, 0xf); - r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS); + r = run_filter_test(vcpu, &e, 1, KVM_PMU_EVENT_FLAG_MASKED_EVENTS, + KVM_PMU_EVENT_ALLOW, 0); TEST_ASSERT(r == 0, "Valid PMU Event Filter is failing"); }

From: Jinrong Liang cloudliang@tencent.com

Update the documentation for the KVM_SET_PMU_EVENT_FILTER ioctl to include a detailed description of how fixed performance events are handled in the pmu filter. The action and fixed_counter_bitmap members of the pmu filter to determine whether fixed performance events can be programmed by the guest. This information is helpful for correctly configuring the fixed_counter_bitmap and action fields to filter fixed performance events.

Suggested-by: Like Xu likexu@tencent.com Signed-off-by: Jinrong Liang cloudliang@tencent.com --- Documentation/virt/kvm/api.rst | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index a69e91088d76..036f5b1a39af 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -5122,6 +5122,27 @@ Valid values for 'action':: #define KVM_PMU_EVENT_ALLOW 0 #define KVM_PMU_EVENT_DENY 1

+Via this API, KVM userspace can also control the behavior of the VM's fixed +counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields. + +Specifically, KVM follows the following pseudo-code when determining whether to +allow the guest FixCtr[i] to count its pre-defined fixed event: + + FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) || + (action == DENY) && !(bitmap & BIT(i)); + FixCtr[i]_is_denied = !FixCtr[i]_is_allowed; + +Note once this API interface is called, the default zero value of the field +"fixed_counter_bitmap" will implicitly affect all fixed counters, even if it's +expected to be used only to control the events on generic counters. + +In addition, pre-defined performance events on the fixed counters already have +event_select and unit_mask values defined, which means userspace can also +control fixed counters by configuring "action"+ "events" fields. + +When there is a contradiction between these two polices, the fixed performance +counter will only follow the rule of the pseudo-code above. + 4.121 KVM_PPC_SVM_OFF ---------------------

From: Jinrong Liang cloudliang@tencent.com

Add tests to cover that pmu_event_filter works as expected when it's applied to fixed performance counters, even if there is none fixed counter exists (e.g. Intel guest pmu version=1 or AMD guest).

Signed-off-by: Jinrong Liang cloudliang@tencent.com --- .../kvm/x86_64/pmu_event_filter_test.c | 109 ++++++++++++++++++ 1 file changed, 109 insertions(+)

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 a3d5c30ce914..0f54c53d7fff 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 @@ -31,6 +31,7 @@ #define PMU_EVENT_FILTER_INVALID_ACTION (KVM_PMU_EVENT_DENY + 1) #define PMU_EVENT_FILTER_INVALID_FLAGS (KVM_PMU_EVENT_FLAG_MASKED_EVENTS + 1) #define PMU_EVENT_FILTER_INVALID_NEVENTS (MAX_FILTER_EVENTS + 1) +#define INTEL_PMC_IDX_FIXED 32

/* * This is how the event selector and unit mask are stored in an AMD @@ -817,6 +818,113 @@ static void test_filter_ioctl(struct kvm_vcpu *vcpu) } }

+static void intel_guest_run_fixed_counters(uint8_t fixed_ctr_idx) +{ + for (;;) { + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); + wrmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx, 0); + + /* 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)); + __asm__ __volatile__("loop ." : "+c"((int){NUM_BRANCHES})); + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0); + + GUEST_SYNC(rdmsr(MSR_CORE_PERF_FIXED_CTR0 + fixed_ctr_idx)); + } +} + +static struct kvm_vcpu *new_vcpu(void *guest_code) +{ + struct kvm_vm *vm; + struct kvm_vcpu *vcpu; + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + vm_init_descriptor_tables(vm); + vcpu_init_descriptor_tables(vcpu); + + return vcpu; +} + +static void free_vcpu(struct kvm_vcpu *vcpu) +{ + kvm_vm_free(vcpu->vm); +} + +static uint64_t test_fixed_ctr_without_filter(struct kvm_vcpu *vcpu) +{ + return run_vcpu_to_sync(vcpu); +} + +static const uint32_t actions[] = { + KVM_PMU_EVENT_ALLOW, + KVM_PMU_EVENT_DENY, +}; + +static uint64_t test_fixed_ctr_with_filter(struct kvm_vcpu *vcpu, + uint32_t action, + uint32_t bitmap) +{ + struct kvm_pmu_event_filter *f; + uint64_t r; + + f = create_pmu_event_filter(0, 0, action, 0, bitmap); + r = test_with_filter(vcpu, f); + free(f); + return r; +} + +static bool fixed_ctr_is_allowed(uint8_t idx, uint32_t action, uint32_t bitmap) +{ + return (action == KVM_PMU_EVENT_ALLOW && (bitmap & BIT_ULL(idx))) || + (action == KVM_PMU_EVENT_DENY && !(bitmap & BIT_ULL(idx))); +} + +static void test_fixed_ctr_action_and_bitmap(struct kvm_vcpu *vcpu, + uint8_t fixed_ctr_idx, + uint8_t max_fixed_num) +{ + uint8_t i; + uint32_t bitmap; + uint64_t count; + bool expected; + + /* + * Check the fixed performance counter can count normally works when + * KVM userspace doesn't set any pmu filter. + */ + TEST_ASSERT(max_fixed_num && test_fixed_ctr_without_filter(vcpu), + "Fixed counter does not exist or does not work as expected."); + + for (i = 0; i < ARRAY_SIZE(actions); i++) { + for (bitmap = 0; bitmap < BIT_ULL(max_fixed_num); bitmap++) { + expected = fixed_ctr_is_allowed(fixed_ctr_idx, actions[i], bitmap); + count = test_fixed_ctr_with_filter(vcpu, actions[i], bitmap); + + TEST_ASSERT(expected == !!count, + "Fixed event filter does not work as expected."); + } + } +} + +static void test_fixed_counter_bitmap(void) +{ + struct kvm_vcpu *vcpu; + uint8_t idx, max_fixed_num = get_kvm_supported_fixed_num(); + + /* + * Check that pmu_event_filter works as expected when it's applied to + * fixed performance counters. + */ + for (idx = 0; idx < max_fixed_num; idx++) { + vcpu = new_vcpu(intel_guest_run_fixed_counters); + vcpu_args_set(vcpu, 1, idx); + test_fixed_ctr_action_and_bitmap(vcpu, idx, max_fixed_num); + free_vcpu(vcpu); + } +} + int main(int argc, char *argv[]) { void (*guest_code)(void); @@ -860,6 +968,7 @@ int main(int argc, char *argv[]) kvm_vm_free(vm);

test_pmu_config_disable(guest_code); + test_fixed_counter_bitmap();

return 0; }

From: Jinrong Liang cloudliang@tencent.com

Add test to verify the behavior of the pmu event filter when an incomplete kvm_pmu_event_filter structure is used. By running the test, we can ensure that the pmu event filter correctly handles incomplete structures and does not allow events to be counted when they should not be.

Signed-off-by: Jinrong Liang cloudliang@tencent.com --- .../kvm/x86_64/pmu_event_filter_test.c | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+)

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 9be4c6f8fb7e..a6b6e0d086ae 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 @@ -881,6 +881,24 @@ static bool fixed_ctr_is_allowed(uint8_t idx, uint32_t action, uint32_t bitmap) (action == KVM_PMU_EVENT_DENY && !(bitmap & BIT_ULL(idx))); }

+struct incompatible_pmu_event_filter { + __u32 action; + __u32 nevents; + __u32 fixed_counter_bitmap; +}; + +static uint64_t test_incompatible_filter(struct kvm_vcpu *vcpu, uint32_t action, + uint32_t bitmap) +{ + struct incompatible_pmu_event_filter err_f; + + err_f.action = action; + err_f.fixed_counter_bitmap = bitmap; + ioctl((vcpu->vm)->fd, KVM_SET_PMU_EVENT_FILTER, &err_f.action); + + return run_vcpu_to_sync(vcpu); +} + static void test_fixed_ctr_action_and_bitmap(struct kvm_vcpu *vcpu, uint8_t fixed_ctr_idx, uint8_t max_fixed_num) @@ -918,6 +936,11 @@ static void test_fixed_ctr_action_and_bitmap(struct kvm_vcpu *vcpu,

TEST_ASSERT(expected == !!count, "Fixed event filter does not work as expected."); + + /* Test incompatible event filter works as expected. */ + count = test_incompatible_filter(vcpu, actions[i], bitmap); + TEST_ASSERT(expected == !!count, + "Incompatible filter does not work as expected."); } } }