[PATCH 0/2] KVM: selftests: steal_time cleanups and timespec rework

[PATCH 0/2] KVM: selftests: steal_time cleanups and timespec rework

[Andrew Jones]

The first patch is a couple changes to steal_time that came to mind
after posting. The second one reworks the timespec functions and
their use. It then applies them to the fixing of the stop condition
of steal_time:do_steal_time

Andrew Jones (2):
  fixup! KVM: selftests: Introduce steal-time test
  KVM: selftests: Rework timespec functions and usage

 .../selftests/kvm/demand_paging_test.c        | 37 +++++++---------
 .../testing/selftests/kvm/include/test_util.h |  3 +-
 tools/testing/selftests/kvm/lib/test_util.c   | 42 +++++++++++--------
 tools/testing/selftests/kvm/steal_time.c      | 39 ++++++++---------
 4 files changed, 60 insertions(+), 61 deletions(-)

-- 
2.21.1

[PATCH 1/2] fixup! KVM: selftests: Introduce steal-time test

[Andrew Jones]

Change the pr_info's to printf's as they're already guarded by verbose,
so shouldn't be dependent on QUIET. Also remove a pointless TEST_ASSERT.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 tools/testing/selftests/kvm/steal_time.c | 37 +++++++++++-------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index f976ac5e896a..21990d653099 100644
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -91,18 +91,18 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpuid)
 	struct kvm_steal_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpuid]);
 	int i;
 
-	pr_info("VCPU%d:\n", vcpuid);
-	pr_info("    steal:     %lld\n", st->steal);
-	pr_info("    version:   %d\n", st->version);
-	pr_info("    flags:     %d\n", st->flags);
-	pr_info("    preempted: %d\n", st->preempted);
-	pr_info("    u8_pad:    ");
+	printf("VCPU%d:\n", vcpuid);
+	printf("    steal:     %lld\n", st->steal);
+	printf("    version:   %d\n", st->version);
+	printf("    flags:     %d\n", st->flags);
+	printf("    preempted: %d\n", st->preempted);
+	printf("    u8_pad:    ");
 	for (i = 0; i < 3; ++i)
-		pr_info("%d", st->u8_pad[i]);
-	pr_info("\n    pad:       ");
+		printf("%d", st->u8_pad[i]);
+	printf("\n    pad:       ");
 	for (i = 0; i < 11; ++i)
-		pr_info("%d", st->pad[i]);
-	pr_info("\n");
+		printf("%d", st->pad[i]);
+	printf("\n");
 }
 
 #elif defined(__aarch64__)
@@ -211,10 +211,10 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpuid)
 {
 	struct st_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpuid]);
 
-	pr_info("VCPU%d:\n", vcpuid);
-	pr_info("    rev:     %d\n", st->rev);
-	pr_info("    attr:    %d\n", st->attr);
-	pr_info("    st_time: %ld\n", st->st_time);
+	printf("VCPU%d:\n", vcpuid);
+	printf("    rev:     %d\n", st->rev);
+	printf("    attr:    %d\n", st->attr);
+	printf("    st_time: %ld\n", st->st_time);
 }
 
 #endif
@@ -326,9 +326,6 @@ int main(int ac, char **av)
 		while (get_run_delay() - run_delay < MIN_RUN_DELAY_NS);
 		pthread_join(thread, NULL);
 		run_delay = get_run_delay() - run_delay;
-		TEST_ASSERT(run_delay >= MIN_RUN_DELAY_NS,
-			    "Expected run_delay >= %ld, got %ld",
-			    MIN_RUN_DELAY_NS, run_delay);
 
 		/* Run VCPU again to confirm stolen time is consistent with run_delay */
 		run_vcpu(vm, i);
@@ -339,11 +336,11 @@ int main(int ac, char **av)
 			    run_delay, stolen_time);
 
 		if (verbose) {
-			pr_info("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld", i,
+			printf("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld", i,
 				guest_stolen_time[i], stolen_time);
 			if (stolen_time == run_delay)
-				pr_info(" (BONUS: guest test-stolen-time even exactly matches test-run_delay)");
-			pr_info("\n");
+				printf(" (BONUS: guest test-stolen-time even exactly matches test-run_delay)");
+			printf("\n");
 			steal_time_dump(vm, i);
 		}
 	}
-- 
2.21.1

[PATCH 2/2] KVM: selftests: Rework timespec functions and usage

[Andrew Jones]

The steal_time test's timespec stop condition was wrong and should have
used the timespec functions instead to avoid being wrong, but
timespec_diff had a strange interface. Rework all the timespec API and
its use.

Signed-off-by: Andrew Jones <drjones@redhat.com>
---
 .../selftests/kvm/demand_paging_test.c        | 37 +++++++---------
 .../testing/selftests/kvm/include/test_util.h |  3 +-
 tools/testing/selftests/kvm/lib/test_util.c   | 42 +++++++++++--------
 tools/testing/selftests/kvm/steal_time.c      |  2 +-
 4 files changed, 43 insertions(+), 41 deletions(-)

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
index d82f7bc060c3..360cd3ea4cd6 100644
--- a/tools/testing/selftests/kvm/demand_paging_test.c
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -117,8 +117,7 @@ static void *vcpu_worker(void *data)
 	struct kvm_vm *vm = args->vm;
 	int vcpu_id = args->vcpu_id;
 	struct kvm_run *run;
-	struct timespec start;
-	struct timespec end;
+	struct timespec start, end, ts_diff;
 
 	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
 	run = vcpu_state(vm, vcpu_id);
@@ -135,9 +134,9 @@ static void *vcpu_worker(void *data)
 	}
 
 	clock_gettime(CLOCK_MONOTONIC, &end);
-	PER_VCPU_DEBUG("vCPU %d execution time: %lld.%.9lds\n", vcpu_id,
-		       (long long)(timespec_diff(start, end).tv_sec),
-		       timespec_diff(start, end).tv_nsec);
+	ts_diff = timespec_sub(end, start);
+	PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
+		       ts_diff.tv_sec, ts_diff.tv_nsec);
 
 	return NULL;
 }
@@ -201,8 +200,8 @@ static int handle_uffd_page_request(int uffd, uint64_t addr)
 
 	clock_gettime(CLOCK_MONOTONIC, &end);
 
-	PER_PAGE_DEBUG("UFFDIO_COPY %d \t%lld ns\n", tid,
-		       (long long)timespec_to_ns(timespec_diff(start, end)));
+	PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
+		       timespec_to_ns(timespec_sub(end, start)));
 	PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
 		       host_page_size, addr, tid);
 
@@ -224,8 +223,7 @@ static void *uffd_handler_thread_fn(void *arg)
 	int pipefd = uffd_args->pipefd;
 	useconds_t delay = uffd_args->delay;
 	int64_t pages = 0;
-	struct timespec start;
-	struct timespec end;
+	struct timespec start, end, ts_diff;
 
 	clock_gettime(CLOCK_MONOTONIC, &start);
 	while (!quit_uffd_thread) {
@@ -295,11 +293,10 @@ static void *uffd_handler_thread_fn(void *arg)
 	}
 
 	clock_gettime(CLOCK_MONOTONIC, &end);
-	PER_VCPU_DEBUG("userfaulted %ld pages over %lld.%.9lds. (%f/sec)\n",
-		       pages, (long long)(timespec_diff(start, end).tv_sec),
-		       timespec_diff(start, end).tv_nsec, pages /
-		       ((double)timespec_diff(start, end).tv_sec +
-			(double)timespec_diff(start, end).tv_nsec / 100000000.0));
+	ts_diff = timespec_sub(end, start);
+	PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
+		       pages, ts_diff.tv_sec, ts_diff.tv_nsec,
+		       pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
 
 	return NULL;
 }
@@ -360,13 +357,12 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
 	pthread_t *vcpu_threads;
 	pthread_t *uffd_handler_threads = NULL;
 	struct uffd_handler_args *uffd_args = NULL;
+	struct timespec start, end, ts_diff;
 	int *pipefds = NULL;
 	struct kvm_vm *vm;
 	uint64_t guest_num_pages;
 	int vcpu_id;
 	int r;
-	struct timespec start;
-	struct timespec end;
 
 	vm = create_vm(mode, vcpus, vcpu_memory_bytes);
 
@@ -514,12 +510,11 @@ static void run_test(enum vm_guest_mode mode, bool use_uffd,
 		}
 	}
 
-	pr_info("Total guest execution time: %lld.%.9lds\n",
-		(long long)(timespec_diff(start, end).tv_sec),
-		timespec_diff(start, end).tv_nsec);
+	ts_diff = timespec_sub(end, start);
+	pr_info("Total guest execution time: %ld.%.9lds\n",
+		ts_diff.tv_sec, ts_diff.tv_nsec);
 	pr_info("Overall demand paging rate: %f pgs/sec\n",
-		guest_num_pages / ((double)timespec_diff(start, end).tv_sec +
-		(double)timespec_diff(start, end).tv_nsec / 100000000.0));
+		guest_num_pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
 
 	ucall_uninit(vm);
 	kvm_vm_free(vm);
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index f588ad1403f1..5eb01bf51b86 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -61,7 +61,8 @@ void test_assert(bool exp, const char *exp_str,
 size_t parse_size(const char *size);
 
 int64_t timespec_to_ns(struct timespec ts);
-struct timespec timespec_diff(struct timespec start, struct timespec end);
 struct timespec timespec_add_ns(struct timespec ts, int64_t ns);
+struct timespec timespec_add(struct timespec ts1, struct timespec ts2);
+struct timespec timespec_sub(struct timespec ts1, struct timespec ts2);
 
 #endif /* SELFTEST_KVM_TEST_UTIL_H */
diff --git a/tools/testing/selftests/kvm/lib/test_util.c b/tools/testing/selftests/kvm/lib/test_util.c
index ee12c4b9ae05..ac9145a9c6b9 100644
--- a/tools/testing/selftests/kvm/lib/test_util.c
+++ b/tools/testing/selftests/kvm/lib/test_util.c
@@ -56,21 +56,6 @@ int64_t timespec_to_ns(struct timespec ts)
 	return (int64_t)ts.tv_nsec + 1000000000LL * (int64_t)ts.tv_sec;
 }
 
-struct timespec timespec_diff(struct timespec start, struct timespec end)
-{
-	struct timespec temp;
-
-	if ((end.tv_nsec - start.tv_nsec) < 0) {
-		temp.tv_sec = end.tv_sec - start.tv_sec - 1;
-		temp.tv_nsec = 1000000000LL + end.tv_nsec - start.tv_nsec;
-	} else {
-		temp.tv_sec = end.tv_sec - start.tv_sec;
-		temp.tv_nsec = end.tv_nsec - start.tv_nsec;
-	}
-
-	return temp;
-}
-
 struct timespec timespec_add_ns(struct timespec ts, int64_t ns)
 {
 	struct timespec res;
@@ -78,14 +63,35 @@ struct timespec timespec_add_ns(struct timespec ts, int64_t ns)
 	res.tv_sec = ts.tv_sec;
 	res.tv_nsec = ts.tv_nsec + ns;
 
-	if (res.tv_nsec > 1000000000UL) {
-		res.tv_sec += 1;
-		res.tv_nsec -= 1000000000UL;
+	if (res.tv_nsec > 0) {
+		while (res.tv_nsec > 1000000000LL) {
+			res.tv_sec += 1;
+			res.tv_nsec -= 1000000000LL;
+		}
+	} else {
+		while (res.tv_nsec < 1000000000LL) {
+			res.tv_sec -= 1;
+			res.tv_nsec += 1000000000LL;
+		}
 	}
 
 	return res;
 }
 
+struct timespec timespec_add(struct timespec ts1, struct timespec ts2)
+{
+	int64_t ns1 = timespec_to_ns(ts1);
+	int64_t ns2 = timespec_to_ns(ts2);
+	return timespec_add_ns((struct timespec){0}, ns1 + ns2);
+}
+
+struct timespec timespec_sub(struct timespec ts1, struct timespec ts2)
+{
+	int64_t ns1 = timespec_to_ns(ts1);
+	int64_t ns2 = timespec_to_ns(ts2);
+	return timespec_add_ns((struct timespec){0}, ns1 - ns2);
+}
+
 void print_skip(const char *fmt, ...)
 {
 	va_list ap;
diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index 21990d653099..86f30eda0ae7 100644
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -242,7 +242,7 @@ static void *do_steal_time(void *arg)
 
 	while (1) {
 		clock_gettime(CLOCK_MONOTONIC, &ts);
-		if (ts.tv_sec > stop.tv_sec || ts.tv_nsec >= stop.tv_nsec)
+		if (timespec_to_ns(timespec_sub(ts, stop)) >= 0)
 			break;
 	}
 
-- 
2.21.1