[PATCH v4 14/15] KVM: riscv: selftests: Add a test for PMU snapshot functionality
From: Atish Patra
Date: Wed Feb 28 2024 - 20:09:44 EST
Verify PMU snapshot functionality by setting up the shared memory
correctly and reading the counter values from the shared memory
instead of the CSR.
Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
---
.../selftests/kvm/include/riscv/processor.h | 25 ++++
.../selftests/kvm/lib/riscv/processor.c | 12 ++
tools/testing/selftests/kvm/riscv/sbi_pmu.c | 124 ++++++++++++++++++
3 files changed, 161 insertions(+)
diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
index a49a39c8e8d4..e114d039e87b 100644
--- a/tools/testing/selftests/kvm/include/riscv/processor.h
+++ b/tools/testing/selftests/kvm/include/riscv/processor.h
@@ -173,6 +173,7 @@ enum sbi_ext_id {
};
enum sbi_ext_base_fid {
+ SBI_EXT_BASE_GET_IMP_VERSION = 2,
SBI_EXT_BASE_PROBE_EXT = 3,
};
@@ -201,6 +202,12 @@ union sbi_pmu_ctr_info {
};
};
+struct riscv_pmu_snapshot_data {
+ u64 ctr_overflow_mask;
+ u64 ctr_values[64];
+ u64 reserved[447];
+};
+
struct sbiret {
long error;
long value;
@@ -247,6 +254,14 @@ enum sbi_pmu_ctr_type {
#define SBI_PMU_STOP_FLAG_RESET (1 << 0)
#define SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT BIT(1)
+#define SBI_STA_SHMEM_DISABLE -1
+
+/* SBI spec version fields */
+#define SBI_SPEC_VERSION_DEFAULT 0x1
+#define SBI_SPEC_VERSION_MAJOR_SHIFT 24
+#define SBI_SPEC_VERSION_MAJOR_MASK 0x7f
+#define SBI_SPEC_VERSION_MINOR_MASK 0xffffff
+
struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
unsigned long arg1, unsigned long arg2,
unsigned long arg3, unsigned long arg4,
@@ -254,6 +269,16 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
bool guest_sbi_probe_extension(int extid, long *out_val);
+/* Make SBI version */
+static inline unsigned long sbi_mk_version(unsigned long major,
+ unsigned long minor)
+{
+ return ((major & SBI_SPEC_VERSION_MAJOR_MASK) <<
+ SBI_SPEC_VERSION_MAJOR_SHIFT) | minor;
+}
+
+unsigned long get_host_sbi_impl_version(void);
+
static inline void local_irq_enable(void)
{
csr_set(CSR_SSTATUS, SR_SIE);
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index ec66d331a127..b0162d923e38 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -499,3 +499,15 @@ bool guest_sbi_probe_extension(int extid, long *out_val)
return true;
}
+
+unsigned long get_host_sbi_impl_version(void)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_GET_IMP_VERSION, 0,
+ 0, 0, 0, 0, 0);
+
+ GUEST_ASSERT(!ret.error);
+
+ return ret.value;
+}
diff --git a/tools/testing/selftests/kvm/riscv/sbi_pmu.c b/tools/testing/selftests/kvm/riscv/sbi_pmu.c
index fc1fc5eea99e..8ea2a6db6610 100644
--- a/tools/testing/selftests/kvm/riscv/sbi_pmu.c
+++ b/tools/testing/selftests/kvm/riscv/sbi_pmu.c
@@ -21,6 +21,11 @@
#define RISCV_MAX_PMU_COUNTERS 64
union sbi_pmu_ctr_info ctrinfo_arr[RISCV_MAX_PMU_COUNTERS];
+/* Snapshot shared memory data */
+#define PMU_SNAPSHOT_GPA_BASE (1 << 30)
+static void *snapshot_gva;
+static vm_paddr_t snapshot_gpa;
+
/* Cache the available counters in a bitmask */
static unsigned long counter_mask_available;
@@ -173,6 +178,20 @@ static void stop_counter(unsigned long counter, unsigned long stop_flags)
counter, ret.error);
}
+static void snapshot_set_shmem(vm_paddr_t gpa, unsigned long flags)
+{
+ unsigned long lo = (unsigned long)gpa;
+#if __riscv_xlen == 32
+ unsigned long hi = (unsigned long)(gpa >> 32);
+#else
+ unsigned long hi = gpa == -1 ? -1 : 0;
+#endif
+ struct sbiret ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_SNAPSHOT_SET_SHMEM,
+ lo, hi, flags, 0, 0, 0);
+
+ GUEST_ASSERT(ret.value == 0 && ret.error == 0);
+}
+
static void test_pmu_event(unsigned long event)
{
unsigned long counter;
@@ -207,6 +226,43 @@ static void test_pmu_event(unsigned long event)
stop_counter(counter, SBI_PMU_STOP_FLAG_RESET);
}
+static void test_pmu_event_snapshot(unsigned long event)
+{
+ unsigned long counter;
+ unsigned long counter_value_pre, counter_value_post;
+ unsigned long counter_init_value = 100;
+ struct riscv_pmu_snapshot_data *snapshot_data = snapshot_gva;
+
+ counter = get_counter_index(0, counter_mask_available, 0, event);
+ counter_value_pre = read_counter(counter, ctrinfo_arr[counter]);
+
+ /* Do not set the initial value */
+ start_counter(counter, 0, 0);
+ dummy_func_loop(10000);
+
+ stop_counter(counter, SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT);
+
+ /* The counter value is updated w.r.t relative index of cbase */
+ counter_value_post = READ_ONCE(snapshot_data->ctr_values[0]);
+ __GUEST_ASSERT(counter_value_post > counter_value_pre,
+ "counter_value_post %lx counter_value_pre %lx\n",
+ counter_value_post, counter_value_pre);
+
+ /* Now set the initial value and compare */
+ WRITE_ONCE(snapshot_data->ctr_values[0], counter_init_value);
+ start_counter(counter, SBI_PMU_START_FLAG_INIT_FROM_SNAPSHOT, 0);
+ dummy_func_loop(10000);
+
+ stop_counter(counter, SBI_PMU_STOP_FLAG_TAKE_SNAPSHOT);
+
+ counter_value_post = READ_ONCE(snapshot_data->ctr_values[0]);
+ __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_counter(counter, SBI_PMU_STOP_FLAG_RESET);
+}
+
static void test_invalid_event(void)
{
struct sbiret ret;
@@ -270,6 +326,41 @@ static void test_pmu_basic_sanity(int cpu)
GUEST_DONE();
}
+static void test_pmu_events_snaphost(int cpu)
+{
+ long out_val = 0;
+ bool probe;
+ int num_counters = 0;
+ unsigned long sbi_impl_version;
+ struct riscv_pmu_snapshot_data *snapshot_data = snapshot_gva;
+ int i;
+
+ probe = guest_sbi_probe_extension(SBI_EXT_PMU, &out_val);
+ GUEST_ASSERT(probe && out_val == 1);
+
+ sbi_impl_version = get_host_sbi_impl_version();
+ if (sbi_impl_version >= sbi_mk_version(2, 0))
+ __GUEST_ASSERT(0, "SBI implementation version doesn't support PMU Snapshot");
+
+ snapshot_set_shmem(snapshot_gpa, 0);
+
+ /* Get the counter details */
+ num_counters = get_num_counters();
+ update_counter_info(num_counters);
+
+ /* Validate shared memory access */
+ GUEST_ASSERT_EQ(READ_ONCE(snapshot_data->ctr_overflow_mask), 0);
+ for (i = 0; i < num_counters; i++) {
+ if (counter_mask_available & (1UL << i))
+ GUEST_ASSERT_EQ(READ_ONCE(snapshot_data->ctr_values[i]), 0);
+ }
+ /* Only these two events are guranteed to be present */
+ test_pmu_event_snapshot(SBI_PMU_HW_CPU_CYCLES);
+ test_pmu_event_snapshot(SBI_PMU_HW_INSTRUCTIONS);
+
+ GUEST_DONE();
+}
+
static void run_vcpu(struct kvm_vcpu *vcpu)
{
struct ucall uc;
@@ -328,6 +419,36 @@ static void test_vm_events_test(void *guest_code)
test_vm_destroy(vm);
}
+static void test_vm_setup_snapshot_mem(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
+{
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, PMU_SNAPSHOT_GPA_BASE, 1, 1, 0);
+ /* PMU Snapshot requires single page only */
+ virt_map(vm, PMU_SNAPSHOT_GPA_BASE, PMU_SNAPSHOT_GPA_BASE, 1);
+
+ /* PMU_SNAPSHOT_GPA_BASE is identity mapped */
+ snapshot_gva = (void *)(PMU_SNAPSHOT_GPA_BASE);
+ snapshot_gpa = addr_gva2gpa(vcpu->vm, (vm_vaddr_t)snapshot_gva);
+ sync_global_to_guest(vcpu->vm, snapshot_gva);
+ sync_global_to_guest(vcpu->vm, snapshot_gpa);
+}
+
+static void test_vm_events_snapshot_test(void *guest_code)
+{
+ struct kvm_vm *vm = NULL;
+ struct kvm_vcpu *vcpu = NULL;
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ __TEST_REQUIRE(__vcpu_has_ext(vcpu, RISCV_ISA_EXT_REG(KVM_RISCV_SBI_EXT_PMU)),
+ "SBI PMU not available, skipping test");
+
+ test_vm_setup_snapshot_mem(vm, vcpu);
+
+ vcpu_args_set(vcpu, 1, 0);
+ run_vcpu(vcpu);
+
+ test_vm_destroy(vm);
+}
+
int main(void)
{
test_vm_basic_test(test_pmu_basic_sanity);
@@ -336,5 +457,8 @@ int main(void)
test_vm_events_test(test_pmu_events);
pr_info("SBI PMU event verification test : PASS\n");
+ test_vm_events_snapshot_test(test_pmu_events_snaphost);
+ pr_info("SBI PMU event verification with snapshot test : PASS\n");
+
return 0;
}
--
2.34.1