Add a test for verifying overflow interrupt. Currently, it relies on overflow support on cycle/instret events. This test works for cycle/ instret events which support sampling via hpmcounters on the platform. There are no ISA extensions to detect if a platform supports that. Thus, this test will fail on platform with virtualization but doesn't support overflow on these two events.
Reviewed-by: Anup Patel anup@brainfault.org Signed-off-by: Atish Patra atishp@rivosinc.com --- .../selftests/kvm/riscv/sbi_pmu_test.c | 114 ++++++++++++++++++ 1 file changed, 114 insertions(+)
diff --git a/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c index 7d195be5c3d9..451db956b885 100644 --- a/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c +++ b/tools/testing/selftests/kvm/riscv/sbi_pmu_test.c @@ -14,6 +14,7 @@ #include "test_util.h" #include "processor.h" #include "sbi.h" +#include "arch_timer.h"
/* Maximum counters(firmware + hardware) */ #define RISCV_MAX_PMU_COUNTERS 64 @@ -24,6 +25,9 @@ union sbi_pmu_ctr_info ctrinfo_arr[RISCV_MAX_PMU_COUNTERS]; static void *snapshot_gva; static vm_paddr_t snapshot_gpa;
+static int vcpu_shared_irq_count; +static int counter_in_use; + /* Cache the available counters in a bitmask */ static unsigned long counter_mask_available;
@@ -117,6 +121,31 @@ static void guest_illegal_exception_handler(struct ex_regs *regs) regs->epc += 4; }
+static void guest_irq_handler(struct ex_regs *regs) +{ + unsigned int irq_num = regs->cause & ~CAUSE_IRQ_FLAG; + struct riscv_pmu_snapshot_data *snapshot_data = snapshot_gva; + unsigned long overflown_mask; + unsigned long counter_val = 0; + + /* Validate that we are in the correct irq handler */ + GUEST_ASSERT_EQ(irq_num, IRQ_PMU_OVF); + + /* Stop all counters first to avoid further interrupts */ + stop_counter(counter_in_use, SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT); + + csr_clear(CSR_SIP, BIT(IRQ_PMU_OVF)); + + overflown_mask = READ_ONCE(snapshot_data->ctr_overflow_mask); + GUEST_ASSERT(overflown_mask & 0x01); + + WRITE_ONCE(vcpu_shared_irq_count, vcpu_shared_irq_count+1); + + counter_val = READ_ONCE(snapshot_data->ctr_values[0]); + /* Now start the counter to mimick the real driver behavior */ + start_counter(counter_in_use, SBI_PMU_START_FLAG_SET_INIT_VALUE, counter_val); +} + static unsigned long get_counter_index(unsigned long cbase, unsigned long cmask, unsigned long cflags, unsigned long event) @@ -276,6 +305,33 @@ static void test_pmu_event_snapshot(unsigned long event) stop_reset_counter(counter, 0); }
+static void test_pmu_event_overflow(unsigned long event) +{ + unsigned long counter; + unsigned long counter_value_post; + unsigned long counter_init_value = ULONG_MAX - 10000; + struct riscv_pmu_snapshot_data *snapshot_data = snapshot_gva; + + counter = get_counter_index(0, counter_mask_available, 0, event); + counter_in_use = counter; + + /* The counter value is updated w.r.t relative index of cbase passed to start/stop */ + WRITE_ONCE(snapshot_data->ctr_values[0], counter_init_value); + start_counter(counter, SBI_PMU_START_FLAG_INIT_SNAPSHOT, 0); + dummy_func_loop(10000); + udelay(msecs_to_usecs(2000)); + /* irq handler should have stopped the counter */ + stop_counter(counter, SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT); + + counter_value_post = READ_ONCE(snapshot_data->ctr_values[0]); + /* The counter value after stopping should be less the init value due to overflow */ + __GUEST_ASSERT(counter_value_post < counter_init_value, + "counter_value_post %lx counter_init_value %lx for counter\n", + counter_value_post, counter_init_value); + + stop_reset_counter(counter, 0); +} + static void test_invalid_event(void) { struct sbiret ret; @@ -366,6 +422,34 @@ static void test_pmu_events_snaphost(void) GUEST_DONE(); }
+static void test_pmu_events_overflow(void) +{ + int num_counters = 0; + + /* Verify presence of SBI PMU and minimum requrired SBI version */ + verify_sbi_requirement_assert(); + + snapshot_set_shmem(snapshot_gpa, 0); + csr_set(CSR_IE, BIT(IRQ_PMU_OVF)); + local_irq_enable(); + + /* Get the counter details */ + num_counters = get_num_counters(); + update_counter_info(num_counters); + + /* + * Qemu supports overflow for cycle/instruction. + * This test may fail on any platform that do not support overflow for these two events. + */ + test_pmu_event_overflow(SBI_PMU_HW_CPU_CYCLES); + GUEST_ASSERT_EQ(vcpu_shared_irq_count, 1); + + test_pmu_event_overflow(SBI_PMU_HW_INSTRUCTIONS); + GUEST_ASSERT_EQ(vcpu_shared_irq_count, 2); + + GUEST_DONE(); +} + static void run_vcpu(struct kvm_vcpu *vcpu) { struct ucall uc; @@ -451,6 +535,33 @@ static void test_vm_events_snapshot_test(void *guest_code) test_vm_destroy(vm); }
+static void test_vm_events_overflow(void *guest_code) +{ + struct kvm_vm *vm = NULL; + struct kvm_vcpu *vcpu; + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + __TEST_REQUIRE(__vcpu_has_sbi_ext(vcpu, KVM_RISCV_SBI_EXT_PMU), + "SBI PMU not available, skipping test"); + + __TEST_REQUIRE(__vcpu_has_isa_ext(vcpu, KVM_RISCV_ISA_EXT_SSCOFPMF), + "Sscofpmf is not available, skipping overflow test"); + + + test_vm_setup_snapshot_mem(vm, vcpu); + vm_init_vector_tables(vm); + vm_install_interrupt_handler(vm, guest_irq_handler); + + vcpu_init_vector_tables(vcpu); + /* Initialize guest timer frequency. */ + vcpu_get_reg(vcpu, RISCV_TIMER_REG(frequency), &timer_freq); + sync_global_to_guest(vm, timer_freq); + + run_vcpu(vcpu); + + test_vm_destroy(vm); +} + int main(void) { pr_info("SBI PMU basic test : starting\n"); @@ -463,5 +574,8 @@ int main(void) test_vm_events_snapshot_test(test_pmu_events_snaphost); pr_info("SBI PMU event verification with snapshot test : PASS\n");
+ test_vm_events_overflow(test_pmu_events_overflow); + pr_info("SBI PMU event verification with overflow test : PASS\n"); + return 0; }