diff mbox series

[v4,14/15] KVM: riscv: selftests: Add a test for PMU snapshot functionality

Message ID 20240229010130.1380926-15-atishp@rivosinc.com
State New
Headers show
Series RISC-V SBI v2.0 PMU improvements and Perf sampling in KVM guest | expand

Commit Message

Atish Kumar Patra Feb. 29, 2024, 1:01 a.m. UTC
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@rivosinc.com>
---
 .../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(+)

Comments

Anup Patel March 1, 2024, 4:50 a.m. UTC | #1
On Thu, Feb 29, 2024 at 6:32 AM Atish Patra <atishp@rivosinc.com> wrote:
>
> 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@rivosinc.com>

LGTM.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  .../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
>
Andrew Jones March 2, 2024, 12:13 p.m. UTC | #2
On Wed, Feb 28, 2024 at 05:01:29PM -0800, Atish Patra wrote:
> 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@rivosinc.com>
> ---
>  .../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

unrelated change

> +
> +/* 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;
> +}

We should probably just synch sbi.h into tools, since we need plenty
from it.

> +
> +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);

This function is almost identical to test_pmu_event(). If we change one,
we'll likely have to change the other. We should have a single function
which can be used by both tests. We can do that by passing a function
pointer for the read which is different for non-snapshot and snapshot.

> +}
> +
>  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)

unnecessary cpu parameter

> +{
> +	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))

BIT()

> +			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 */

This comment should go above the memory region add

> +	virt_map(vm, PMU_SNAPSHOT_GPA_BASE, PMU_SNAPSHOT_GPA_BASE, 1);
> +
> +	/* PMU_SNAPSHOT_GPA_BASE is identity mapped */

This comment should go above the virt_map

> +	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;

nit: no need to set to 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)),

RISCV_SBI_EXT_REG

> +				   "SBI PMU not available, skipping test");
> +
> +	test_vm_setup_snapshot_mem(vm, vcpu);
> +
> +	vcpu_args_set(vcpu, 1, 0);

no need to set args

> +	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
>

Thanks,
drew
Atish Kumar Patra April 2, 2024, 8:35 a.m. UTC | #3
On 3/2/24 04:13, Andrew Jones wrote:
> On Wed, Feb 28, 2024 at 05:01:29PM -0800, Atish Patra wrote:
>> 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@rivosinc.com>
>> ---
>>   .../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
> 
> unrelated change
> 

Dropped it.

>> +
>> +/* 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;
>> +}
> 
> We should probably just synch sbi.h into tools, since we need plenty
> from it.
> 

As of now I have created sbi.h and moved all the definitions there. 
There is a still lot of difference between sbi.h. Do we really want to 
bring everything in ? Should we adopt kvmtool like policy to sync sbi.h
or just do it as new test cases need sbi.h?

I can send another version with syncing sbi.h if you still think that's 
better.


>> +
>> +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);
> 
> This function is almost identical to test_pmu_event(). If we change one,
> we'll likely have to change the other. We should have a single function
> which can be used by both tests. We can do that by passing a function
> pointer for the read which is different for non-snapshot and snapshot.
> 

There are more difference than just read function. Stop/start takes 
snapshot specific flag. We also have to update the counter in the shared 
memory. If we combine the two functions to a single one, we will end up 
with bunch of if else condition which I don't like.

I am okay modifying it if you feel strongly about it though.

>> +}
>> +
>>   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)
> 
> unnecessary cpu parameter
> 

Removed.

>> +{
>> +	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))
> 
> BIT()
> 

Done.

>> +			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 */
> 
> This comment should go above the memory region add
> 
>> +	virt_map(vm, PMU_SNAPSHOT_GPA_BASE, PMU_SNAPSHOT_GPA_BASE, 1);
>> +
>> +	/* PMU_SNAPSHOT_GPA_BASE is identity mapped */
> 
> This comment should go above the virt_map
> 

Fixed.

>> +	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;
> 
> nit: no need to set to 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)),
> 
> RISCV_SBI_EXT_REG
> 

Updated to use the new helper functions as suggested in the earlier patch.

>> +				   "SBI PMU not available, skipping test");
>> +
>> +	test_vm_setup_snapshot_mem(vm, vcpu);
>> +
>> +	vcpu_args_set(vcpu, 1, 0);
> 
> no need to set args
> 

Fixed.

>> +	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
>>
> 
> Thanks,
> drew
diff mbox series

Patch

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;
 }