1 files changed, 259 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/arch_timer.c b/tools/testing/selftests/kvm/arch_timer.c
new file mode 100644
index 000000000000..ae1f1a6d8312
--- /dev/null
+++ b/tools/testing/selftests/kvm/arch_timer.c
@@ -0,0 +1,259 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * arch_timer.c - Tests the arch timer IRQ functionality
+ *
+ * The guest's main thread configures the timer interrupt and waits
+ * for it to fire, with a timeout equal to the timer period.
+ * It asserts that the timeout doesn't exceed the timer period plus
+ * a user configurable error margin(default to 100us)
+ *
+ * On the other hand, upon receipt of an interrupt, the guest's interrupt
+ * handler validates the interrupt by checking if the architectural state
+ * is in compliance with the specifications.
+ *
+ * The test provides command-line options to configure the timer's
+ * period (-p), number of vCPUs (-n), iterations per stage (-i) and timer
+ * interrupt arrival error margin (-e). To stress-test the timer stack
+ * even more, an option to migrate the vCPUs across pCPUs (-m), at a
+ * particular rate, is also provided.
+ *
+ * Copyright (c) 2021, Google LLC.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <linux/sizes.h>
+#include <linux/bitmap.h>
+#include <sys/sysinfo.h>
+
+#include "timer_test.h"
+
+struct test_args test_args = {
+	.nr_vcpus = NR_VCPUS_DEF,
+	.nr_iter = NR_TEST_ITERS_DEF,
+	.timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
+	.migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
+	.timer_err_margin_us = TIMER_TEST_ERR_MARGIN_US,
+	.reserved = 1,
+};
+
+struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
+
+static pthread_t pt_vcpu_run[KVM_MAX_VCPUS];
+static unsigned long *vcpu_done_map;
+static pthread_mutex_t vcpu_done_map_lock;
+
+static void *test_vcpu_run(void *arg)
+{
+	unsigned int vcpu_idx = (unsigned long)arg;
+	struct ucall uc;
+	struct kvm_vcpu *vcpu = vcpus[vcpu_idx];
+	struct kvm_vm *vm = vcpu->vm;
+	struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpu_idx];
+
+	vcpu_run(vcpu);
+
+	/* Currently, any exit from guest is an indication of completion */
+	pthread_mutex_lock(&vcpu_done_map_lock);
+	__set_bit(vcpu_idx, vcpu_done_map);
+	pthread_mutex_unlock(&vcpu_done_map_lock);
+
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_SYNC:
+	case UCALL_DONE:
+		break;
+	case UCALL_ABORT:
+		sync_global_from_guest(vm, *shared_data);
+		fprintf(stderr, "Guest assert failed,  vcpu %u; stage; %u; iter: %u\n",
+			vcpu_idx, shared_data->guest_stage, shared_data->nr_iter);
+		REPORT_GUEST_ASSERT(uc);
+		break;
+	default:
+		TEST_FAIL("Unexpected guest exit");
+	}
+
+	pr_info("PASS(vCPU-%d).\n", vcpu_idx);
+
+	return NULL;
+}
+
+static uint32_t test_get_pcpu(void)
+{
+	uint32_t pcpu;
+	unsigned int nproc_conf;
+	cpu_set_t online_cpuset;
+
+	nproc_conf = get_nprocs_conf();
+	sched_getaffinity(0, sizeof(cpu_set_t), &online_cpuset);
+
+	/* Randomly find an available pCPU to place a vCPU on */
+	do {
+		pcpu = rand() % nproc_conf;
+	} while (!CPU_ISSET(pcpu, &online_cpuset));
+
+	return pcpu;
+}
+
+static int test_migrate_vcpu(unsigned int vcpu_idx)
+{
+	int ret;
+	cpu_set_t cpuset;
+	uint32_t new_pcpu = test_get_pcpu();
+
+	CPU_ZERO(&cpuset);
+	CPU_SET(new_pcpu, &cpuset);
+
+	pr_debug("Migrating vCPU: %u to pCPU: %u\n", vcpu_idx, new_pcpu);
+
+	ret = pthread_setaffinity_np(pt_vcpu_run[vcpu_idx],
+				     sizeof(cpuset), &cpuset);
+
+	/* Allow the error where the vCPU thread is already finished */
+	TEST_ASSERT(ret == 0 || ret == ESRCH,
+		    "Failed to migrate the vCPU:%u to pCPU: %u; ret: %d",
+		    vcpu_idx, new_pcpu, ret);
+
+	return ret;
+}
+
+static void *test_vcpu_migration(void *arg)
+{
+	unsigned int i, n_done;
+	bool vcpu_done;
+
+	do {
+		usleep(msecs_to_usecs(test_args.migration_freq_ms));
+
+		for (n_done = 0, i = 0; i < test_args.nr_vcpus; i++) {
+			pthread_mutex_lock(&vcpu_done_map_lock);
+			vcpu_done = test_bit(i, vcpu_done_map);
+			pthread_mutex_unlock(&vcpu_done_map_lock);
+
+			if (vcpu_done) {
+				n_done++;
+				continue;
+			}
+
+			test_migrate_vcpu(i);
+		}
+	} while (test_args.nr_vcpus != n_done);
+
+	return NULL;
+}
+
+static void test_run(struct kvm_vm *vm)
+{
+	pthread_t pt_vcpu_migration;
+	unsigned int i;
+	int ret;
+
+	pthread_mutex_init(&vcpu_done_map_lock, NULL);
+	vcpu_done_map = bitmap_zalloc(test_args.nr_vcpus);
+	TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap");
+
+	for (i = 0; i < (unsigned long)test_args.nr_vcpus; i++) {
+		ret = pthread_create(&pt_vcpu_run[i], NULL, test_vcpu_run,
+				     (void *)(unsigned long)i);
+		TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread", i);
+	}
+
+	/* Spawn a thread to control the vCPU migrations */
+	if (test_args.migration_freq_ms) {
+		srand(time(NULL));
+
+		ret = pthread_create(&pt_vcpu_migration, NULL,
+					test_vcpu_migration, NULL);
+		TEST_ASSERT(!ret, "Failed to create the migration pthread");
+	}
+
+
+	for (i = 0; i < test_args.nr_vcpus; i++)
+		pthread_join(pt_vcpu_run[i], NULL);
+
+	if (test_args.migration_freq_ms)
+		pthread_join(pt_vcpu_migration, NULL);
+
+	bitmap_free(vcpu_done_map);
+}
+
+static void test_print_help(char *name)
+{
+	pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\n"
+		"\t\t    [-m migration_freq_ms] [-o counter_offset]\n"
+		"\t\t    [-e timer_err_margin_us]\n", name);
+	pr_info("\t-n: Number of vCPUs to configure (default: %u; max: %u)\n",
+		NR_VCPUS_DEF, KVM_MAX_VCPUS);
+	pr_info("\t-i: Number of iterations per stage (default: %u)\n",
+		NR_TEST_ITERS_DEF);
+	pr_info("\t-p: Periodicity (in ms) of the guest timer (default: %u)\n",
+		TIMER_TEST_PERIOD_MS_DEF);
+	pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
+		TIMER_TEST_MIGRATION_FREQ_MS);
+	pr_info("\t-o: Counter offset (in counter cycles, default: 0) [aarch64-only]\n");
+	pr_info("\t-e: Interrupt arrival error margin (in us) of the guest timer (default: %u)\n",
+		TIMER_TEST_ERR_MARGIN_US);
+	pr_info("\t-h: print this help screen\n");
+}
+
+static bool parse_args(int argc, char *argv[])
+{
+	int opt;
+
+	while ((opt = getopt(argc, argv, "hn:i:p:m:o:e:")) != -1) {
+		switch (opt) {
+		case 'n':
+			test_args.nr_vcpus = atoi_positive("Number of vCPUs", optarg);
+			if (test_args.nr_vcpus > KVM_MAX_VCPUS) {
+				pr_info("Max allowed vCPUs: %u\n",
+					KVM_MAX_VCPUS);
+				goto err;
+			}
+			break;
+		case 'i':
+			test_args.nr_iter = atoi_positive("Number of iterations", optarg);
+			break;
+		case 'p':
+			test_args.timer_period_ms = atoi_positive("Periodicity", optarg);
+			break;
+		case 'm':
+			test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
+			break;
+		case 'e':
+			test_args.timer_err_margin_us = atoi_non_negative("Error Margin", optarg);
+			break;
+		case 'o':
+			test_args.counter_offset = strtol(optarg, NULL, 0);
+			test_args.reserved = 0;
+			break;
+		case 'h':
+		default:
+			goto err;
+		}
+	}
+
+	return true;
+
+err:
+	test_print_help(argv[0]);
+	return false;
+}
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vm *vm;
+
+	if (!parse_args(argc, argv))
+		exit(KSFT_SKIP);
+
+	__TEST_REQUIRE(!test_args.migration_freq_ms || get_nprocs() >= 2,
+		       "At least two physical CPUs needed for vCPU migration");
+
+	vm = test_vm_create();
+	test_run(vm);
+	test_vm_cleanup(vm);
+
+	return 0;
+}