[PATCH v2 0/2] KVM: selftests: Enable access_tracking_perf_test for arm64

[PATCH v2 0/2] KVM: selftests: Enable access_tracking_perf_test for arm64

[Oliver Upton]

Small series to add support for arm64 to access_tracking_perf_test and
correct a couple bugs along the way.

Tested on Ampere Altra w/ all supported guest modes.

v1 -> v2:
 - Have perf_test_util indicate when to stop vCPU threads (Sean)
 - Collect Gavin's R-b on the second patch. I left off Gavin's R-b on
   the first patch as it was retooled.

v1: https://lore.kernel.org/kvmarm/20221111231946.944807-1-oliver.upton@linux.dev/

Oliver Upton (2):
  KVM: selftests: Have perf_test_util signal when to stop vCPUs
  KVM: selftests: Build access_tracking_perf_test for arm64

 tools/testing/selftests/kvm/Makefile                      | 1 +
 tools/testing/selftests/kvm/access_tracking_perf_test.c   | 8 +-------
 tools/testing/selftests/kvm/include/perf_test_util.h      | 3 +++
 tools/testing/selftests/kvm/lib/perf_test_util.c          | 3 +++
 .../selftests/kvm/memslot_modification_stress_test.c      | 6 +-----
 5 files changed, 9 insertions(+), 12 deletions(-)


base-commit: 30a0b95b1335e12efef89dd78518ed3e4a71a763
-- 
2.38.1.584.g0f3c55d4c2-goog


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[PATCH v2 1/2] KVM: selftests: Have perf_test_util signal when to stop vCPUs

[Oliver Upton]

Signal that a test run is complete through perf_test_args instead of
having tests open code a similar solution. Ensure that the field resets
to false at the beginning of a test run as the structure is reused
between test runs, eliminating a couple of bugs:

access_tracking_perf_test hangs indefinitely on a subsequent test run,
as 'done' remains true. The bug doesn't amount to much right now, as x86
supports a single guest mode. However, this is a precondition of
enabling the test for other architectures with >1 guest mode, like
arm64.

memslot_modification_stress_test has the exact opposite problem, where
subsequent test runs complete immediately as 'run_vcpus' remains false.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
[oliver: added commit message, preserve spin_wait_for_next_iteration()]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 tools/testing/selftests/kvm/access_tracking_perf_test.c   | 8 +-------
 tools/testing/selftests/kvm/include/perf_test_util.h      | 3 +++
 tools/testing/selftests/kvm/lib/perf_test_util.c          | 3 +++
 .../selftests/kvm/memslot_modification_stress_test.c      | 6 +-----
 4 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
index 76c583a07ea2..942370d57392 100644
--- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
+++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
@@ -58,9 +58,6 @@ static enum {
 	ITERATION_MARK_IDLE,
 } iteration_work;
 
-/* Set to true when vCPU threads should exit. */
-static bool done;
-
 /* The iteration that was last completed by each vCPU. */
 static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
 
@@ -211,7 +208,7 @@ static bool spin_wait_for_next_iteration(int *current_iteration)
 	int last_iteration = *current_iteration;
 
 	do {
-		if (READ_ONCE(done))
+		if (READ_ONCE(perf_test_args.stop_vcpus))
 			return false;
 
 		*current_iteration = READ_ONCE(iteration);
@@ -321,9 +318,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	mark_memory_idle(vm, nr_vcpus);
 	access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from idle memory");
 
-	/* Set done to signal the vCPU threads to exit */
-	done = true;
-
 	perf_test_join_vcpu_threads(nr_vcpus);
 	perf_test_destroy_vm(vm);
 }
diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
index eaa88df0555a..536d7c3c3f14 100644
--- a/tools/testing/selftests/kvm/include/perf_test_util.h
+++ b/tools/testing/selftests/kvm/include/perf_test_util.h
@@ -40,6 +40,9 @@ struct perf_test_args {
 	/* Run vCPUs in L2 instead of L1, if the architecture supports it. */
 	bool nested;
 
+	/* Test is done, stop running vCPUs. */
+	bool stop_vcpus;
+
 	struct perf_test_vcpu_args vcpu_args[KVM_MAX_VCPUS];
 };
 
diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
index 9618b37c66f7..ee3f499ccbd2 100644
--- a/tools/testing/selftests/kvm/lib/perf_test_util.c
+++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
@@ -267,6 +267,7 @@ void perf_test_start_vcpu_threads(int nr_vcpus,
 
 	vcpu_thread_fn = vcpu_fn;
 	WRITE_ONCE(all_vcpu_threads_running, false);
+	WRITE_ONCE(perf_test_args.stop_vcpus, false);
 
 	for (i = 0; i < nr_vcpus; i++) {
 		struct vcpu_thread *vcpu = &vcpu_threads[i];
@@ -289,6 +290,8 @@ void perf_test_join_vcpu_threads(int nr_vcpus)
 {
 	int i;
 
+	WRITE_ONCE(perf_test_args.stop_vcpus, true);
+
 	for (i = 0; i < nr_vcpus; i++)
 		pthread_join(vcpu_threads[i].thread, NULL);
 }
diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
index bb1d17a1171b..3a5e4518307c 100644
--- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
+++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
@@ -34,8 +34,6 @@
 static int nr_vcpus = 1;
 static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
 
-static bool run_vcpus = true;
-
 static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args)
 {
 	struct kvm_vcpu *vcpu = vcpu_args->vcpu;
@@ -45,7 +43,7 @@ static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args)
 	run = vcpu->run;
 
 	/* Let the guest access its memory until a stop signal is received */
-	while (READ_ONCE(run_vcpus)) {
+	while (!READ_ONCE(perf_test_args.stop_vcpus)) {
 		ret = _vcpu_run(vcpu);
 		TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
 
@@ -110,8 +108,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
 	add_remove_memslot(vm, p->memslot_modification_delay,
 			   p->nr_memslot_modifications);
 
-	run_vcpus = false;
-
 	perf_test_join_vcpu_threads(nr_vcpus);
 	pr_info("All vCPU threads joined\n");
 
-- 
2.38.1.584.g0f3c55d4c2-goog


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[PATCH v2 2/2] KVM: selftests: Build access_tracking_perf_test for arm64

[Oliver Upton]

Does exactly what it says on the tin.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 tools/testing/selftests/kvm/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 0172eb6cb6ee..4c0ff91a8964 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -156,6 +156,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/psci_test
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_irq
+TEST_GEN_PROGS_aarch64 += access_tracking_perf_test
 TEST_GEN_PROGS_aarch64 += demand_paging_test
 TEST_GEN_PROGS_aarch64 += dirty_log_test
 TEST_GEN_PROGS_aarch64 += dirty_log_perf_test
-- 
2.38.1.584.g0f3c55d4c2-goog


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Re: [PATCH v2 1/2] KVM: selftests: Have perf_test_util signal when to stop vCPUs

[Gavin Shan]

On 11/19/22 5:15 AM, Oliver Upton wrote:
> Signal that a test run is complete through perf_test_args instead of
> having tests open code a similar solution. Ensure that the field resets
> to false at the beginning of a test run as the structure is reused
> between test runs, eliminating a couple of bugs:
> 
> access_tracking_perf_test hangs indefinitely on a subsequent test run,
> as 'done' remains true. The bug doesn't amount to much right now, as x86
> supports a single guest mode. However, this is a precondition of
> enabling the test for other architectures with >1 guest mode, like
> arm64.
> 
> memslot_modification_stress_test has the exact opposite problem, where
> subsequent test runs complete immediately as 'run_vcpus' remains false.
> 
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> [oliver: added commit message, preserve spin_wait_for_next_iteration()]
> Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
> ---
>   tools/testing/selftests/kvm/access_tracking_perf_test.c   | 8 +-------
>   tools/testing/selftests/kvm/include/perf_test_util.h      | 3 +++
>   tools/testing/selftests/kvm/lib/perf_test_util.c          | 3 +++
>   .../selftests/kvm/memslot_modification_stress_test.c      | 6 +-----
>   4 files changed, 8 insertions(+), 12 deletions(-)
> 

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
> index 76c583a07ea2..942370d57392 100644
> --- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
> +++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
> @@ -58,9 +58,6 @@ static enum {
>   	ITERATION_MARK_IDLE,
>   } iteration_work;
>   
> -/* Set to true when vCPU threads should exit. */
> -static bool done;
> -
>   /* The iteration that was last completed by each vCPU. */
>   static int vcpu_last_completed_iteration[KVM_MAX_VCPUS];
>   
> @@ -211,7 +208,7 @@ static bool spin_wait_for_next_iteration(int *current_iteration)
>   	int last_iteration = *current_iteration;
>   
>   	do {
> -		if (READ_ONCE(done))
> +		if (READ_ONCE(perf_test_args.stop_vcpus))
>   			return false;
>   
>   		*current_iteration = READ_ONCE(iteration);
> @@ -321,9 +318,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>   	mark_memory_idle(vm, nr_vcpus);
>   	access_memory(vm, nr_vcpus, ACCESS_READ, "Reading from idle memory");
>   
> -	/* Set done to signal the vCPU threads to exit */
> -	done = true;
> -
>   	perf_test_join_vcpu_threads(nr_vcpus);
>   	perf_test_destroy_vm(vm);
>   }
> diff --git a/tools/testing/selftests/kvm/include/perf_test_util.h b/tools/testing/selftests/kvm/include/perf_test_util.h
> index eaa88df0555a..536d7c3c3f14 100644
> --- a/tools/testing/selftests/kvm/include/perf_test_util.h
> +++ b/tools/testing/selftests/kvm/include/perf_test_util.h
> @@ -40,6 +40,9 @@ struct perf_test_args {
>   	/* Run vCPUs in L2 instead of L1, if the architecture supports it. */
>   	bool nested;
>   
> +	/* Test is done, stop running vCPUs. */
> +	bool stop_vcpus;
> +
>   	struct perf_test_vcpu_args vcpu_args[KVM_MAX_VCPUS];
>   };
>   
> diff --git a/tools/testing/selftests/kvm/lib/perf_test_util.c b/tools/testing/selftests/kvm/lib/perf_test_util.c
> index 9618b37c66f7..ee3f499ccbd2 100644
> --- a/tools/testing/selftests/kvm/lib/perf_test_util.c
> +++ b/tools/testing/selftests/kvm/lib/perf_test_util.c
> @@ -267,6 +267,7 @@ void perf_test_start_vcpu_threads(int nr_vcpus,
>   
>   	vcpu_thread_fn = vcpu_fn;
>   	WRITE_ONCE(all_vcpu_threads_running, false);
> +	WRITE_ONCE(perf_test_args.stop_vcpus, false);
>   
>   	for (i = 0; i < nr_vcpus; i++) {
>   		struct vcpu_thread *vcpu = &vcpu_threads[i];
> @@ -289,6 +290,8 @@ void perf_test_join_vcpu_threads(int nr_vcpus)
>   {
>   	int i;
>   
> +	WRITE_ONCE(perf_test_args.stop_vcpus, true);
> +
>   	for (i = 0; i < nr_vcpus; i++)
>   		pthread_join(vcpu_threads[i].thread, NULL);
>   }
> diff --git a/tools/testing/selftests/kvm/memslot_modification_stress_test.c b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> index bb1d17a1171b..3a5e4518307c 100644
> --- a/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> +++ b/tools/testing/selftests/kvm/memslot_modification_stress_test.c
> @@ -34,8 +34,6 @@
>   static int nr_vcpus = 1;
>   static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
>   
> -static bool run_vcpus = true;
> -
>   static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args)
>   {
>   	struct kvm_vcpu *vcpu = vcpu_args->vcpu;
> @@ -45,7 +43,7 @@ static void vcpu_worker(struct perf_test_vcpu_args *vcpu_args)
>   	run = vcpu->run;
>   
>   	/* Let the guest access its memory until a stop signal is received */
> -	while (READ_ONCE(run_vcpus)) {
> +	while (!READ_ONCE(perf_test_args.stop_vcpus)) {
>   		ret = _vcpu_run(vcpu);
>   		TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
>   
> @@ -110,8 +108,6 @@ static void run_test(enum vm_guest_mode mode, void *arg)
>   	add_remove_memslot(vm, p->memslot_modification_delay,
>   			   p->nr_memslot_modifications);
>   
> -	run_vcpus = false;
> -
>   	perf_test_join_vcpu_threads(nr_vcpus);
>   	pr_info("All vCPU threads joined\n");
>   
> 


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Re: [PATCH v2 0/2] KVM: selftests: Enable access_tracking_perf_test for arm64

[Marc Zyngier]

On Fri, 18 Nov 2022 21:15:01 +0000, Oliver Upton wrote:
> Small series to add support for arm64 to access_tracking_perf_test and
> correct a couple bugs along the way.
> 
> Tested on Ampere Altra w/ all supported guest modes.
> 
> v1 -> v2:
>  - Have perf_test_util indicate when to stop vCPU threads (Sean)
>  - Collect Gavin's R-b on the second patch. I left off Gavin's R-b on
>    the first patch as it was retooled.
> 
> [...]

Applied to next, thanks!

[1/2] KVM: selftests: Have perf_test_util signal when to stop vCPUs
      commit: 9ec1eb1bcceec735fb3c9255cdcdbcc2acf860a0
[2/2] KVM: selftests: Build access_tracking_perf_test for arm64
      commit: 4568180411e0fb5613e217da1c693466e39b9c27

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.



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