[PATCH v5 13/14] KVM: arm64: selftests: Add arch_timer test

Raghavendra Rao Ananta
2021-09-13T20:51:38Z

Add a KVM selftest to validate the arch_timer functionality.
Primarily, the test sets up periodic timer interrupts and
validates the basic architectural expectations upon its receipt.

The test provides command-line options to configure the period
of the timer, number of iterations, and number of vCPUs.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/aarch64/arch_timer.c | 366 ++++++++++++++++++
3 files changed, 368 insertions(+)
create mode 100644 tools/testing/selftests/kvm/aarch64/arch_timer.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 98053d3afbda..c6058df0cd18 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -1,4 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
+/aarch64/arch_timer
/aarch64/debug-exceptions
/aarch64/get-reg-list
/aarch64/psci_cpu_on_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 8342f65c1d96..46d43e706b20 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -84,6 +84,7 @@ TEST_GEN_PROGS_x86_64 += set_memory_region_test
TEST_GEN_PROGS_x86_64 += steal_time
TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test

+TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
TEST_GEN_PROGS_aarch64 += aarch64/psci_cpu_on_test
diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c
new file mode 100644
index 000000000000..3b6ea6a462f4
--- /dev/null
+++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * arch_timer.c - Tests the aarch64 timer IRQ functionality
+ *
+ * The test validates both the virtual and physical timer IRQs using
+ * CVAL and TVAL registers. This consitutes the four stages in the test.
+ * The guest's main thread configures the timer interrupt for a stage
+ * 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.
+ *
+ * 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), and iterations per stage (-i).
+ *
+ * Copyright (c) 2021, Google LLC.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <linux/kvm.h>
+#include <linux/sizes.h>
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "delay.h"
+#include "arch_timer.h"
+#include "gic.h"
+#include "vgic.h"
+
+#define NR_VCPUS_DEF 4
+#define NR_TEST_ITERS_DEF 5
+#define TIMER_TEST_PERIOD_MS_DEF 10
+#define TIMER_TEST_ERR_MARGIN_US 100
+
+struct test_args {
+ int nr_vcpus;
+ int nr_iter;
+ int timer_period_ms;
+};
+
+static struct test_args test_args = {
+ .nr_vcpus = NR_VCPUS_DEF,
+ .nr_iter = NR_TEST_ITERS_DEF,
+ .timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
+};
+
+#define msecs_to_usecs(msec) ((msec) * 1000LL)
+
+#define GICD_BASE_GPA 0x8000000ULL
+#define GICR_BASE_GPA 0x80A0000ULL
+
+enum guest_stage {
+ GUEST_STAGE_VTIMER_CVAL = 1,
+ GUEST_STAGE_VTIMER_TVAL,
+ GUEST_STAGE_PTIMER_CVAL,
+ GUEST_STAGE_PTIMER_TVAL,
+ GUEST_STAGE_MAX,
+};
+
+/* Shared variables between host and guest */
+struct test_vcpu_shared_data {
+ int nr_iter;
+ enum guest_stage guest_stage;
+ uint64_t xcnt;
+};
+
+struct test_vcpu {
+ uint32_t vcpuid;
+ pthread_t pt_vcpu_run;
+ struct kvm_vm *vm;
+};
+
+static struct test_vcpu test_vcpu[KVM_MAX_VCPUS];
+static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
+
+static int vtimer_irq, ptimer_irq;
+
+static void
+guest_configure_timer_action(struct test_vcpu_shared_data *shared_data)
+{
+ switch (shared_data->guest_stage) {
+ case GUEST_STAGE_VTIMER_CVAL:
+ timer_set_next_cval_ms(VIRTUAL, test_args.timer_period_ms);
+ shared_data->xcnt = timer_get_cntct(VIRTUAL);
+ timer_set_ctl(VIRTUAL, CTL_ENABLE);
+ break;
+ case GUEST_STAGE_VTIMER_TVAL:
+ timer_set_next_tval_ms(VIRTUAL, test_args.timer_period_ms);
+ shared_data->xcnt = timer_get_cntct(VIRTUAL);
+ timer_set_ctl(VIRTUAL, CTL_ENABLE);
+ break;
+ case GUEST_STAGE_PTIMER_CVAL:
+ timer_set_next_cval_ms(PHYSICAL, test_args.timer_period_ms);
+ shared_data->xcnt = timer_get_cntct(PHYSICAL);
+ timer_set_ctl(PHYSICAL, CTL_ENABLE);
+ break;
+ case GUEST_STAGE_PTIMER_TVAL:
+ timer_set_next_tval_ms(PHYSICAL, test_args.timer_period_ms);
+ shared_data->xcnt = timer_get_cntct(PHYSICAL);
+ timer_set_ctl(PHYSICAL, CTL_ENABLE);
+ break;
+ default:
+ GUEST_ASSERT(0);
+ }
+}
+
+static void guest_validate_irq(unsigned int intid,
+ struct test_vcpu_shared_data *shared_data)
+{
+ enum guest_stage stage = shared_data->guest_stage;
+ uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
+ unsigned long xctl = 0;
+ unsigned int timer_irq = 0;
+
+ if (stage == GUEST_STAGE_VTIMER_CVAL ||
+ stage == GUEST_STAGE_VTIMER_TVAL) {
+ xctl = timer_get_ctl(VIRTUAL);
+ timer_set_ctl(VIRTUAL, CTL_IMASK);
+ xcnt = timer_get_cntct(VIRTUAL);
+ cval = timer_get_cval(VIRTUAL);
+ timer_irq = vtimer_irq;
+ } else if (stage == GUEST_STAGE_PTIMER_CVAL ||
+ stage == GUEST_STAGE_PTIMER_TVAL) {
+ xctl = timer_get_ctl(PHYSICAL);
+ timer_set_ctl(PHYSICAL, CTL_IMASK);
+ xcnt = timer_get_cntct(PHYSICAL);
+ cval = timer_get_cval(PHYSICAL);
+ timer_irq = ptimer_irq;
+ } else {
+ GUEST_ASSERT(0);
+ }
+
+ xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
+
+ /* Make sure we are dealing with the correct timer IRQ */
+ GUEST_ASSERT_2(intid == timer_irq, intid, timer_irq);
+
+ /* Basic 'timer condition met' check */
+ GUEST_ASSERT_3(xcnt >= cval, xcnt, cval, xcnt_diff_us);
+ GUEST_ASSERT_1(xctl & CTL_ISTATUS, xctl);
+}
+
+static void guest_irq_handler(struct ex_regs *regs)
+{
+ unsigned int intid = gic_get_and_ack_irq();
+ uint32_t cpu = guest_get_vcpuid();
+ struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
+
+ guest_validate_irq(intid, shared_data);
+
+ WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
+
+ gic_set_eoi(intid);
+}
+
+static void guest_run_stage(struct test_vcpu_shared_data *shared_data,
+ enum guest_stage stage)
+{
+ uint32_t irq_iter, config_iter;
+
+ shared_data->guest_stage = stage;
+ shared_data->nr_iter = 0;
+
+ for (config_iter = 0; config_iter < test_args.nr_iter; config_iter++) {
+ /* Setup the next interrupt */
+ guest_configure_timer_action(shared_data);
+
+ /* Setup a timeout for the interrupt to arrive */
+ udelay(msecs_to_usecs(test_args.timer_period_ms) +
+ TIMER_TEST_ERR_MARGIN_US);
+
+ irq_iter = READ_ONCE(shared_data->nr_iter);
+ GUEST_ASSERT_2(config_iter + 1 == irq_iter,
+ config_iter + 1, irq_iter);
+ }
+}
+
+static void guest_code(void)
+{
+ uint32_t cpu = guest_get_vcpuid();
+ struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
+
+ local_irq_disable();
+
+ gic_init(GIC_V3, test_args.nr_vcpus,
+ (void *)GICD_BASE_GPA, (void *)GICR_BASE_GPA);
+
+ timer_set_ctl(VIRTUAL, CTL_IMASK);
+ timer_set_ctl(PHYSICAL, CTL_IMASK);
+
+ gic_irq_enable(vtimer_irq);
+ gic_irq_enable(ptimer_irq);
+ local_irq_enable();
+
+ guest_run_stage(shared_data, GUEST_STAGE_VTIMER_CVAL);
+ guest_run_stage(shared_data, GUEST_STAGE_VTIMER_TVAL);
+ guest_run_stage(shared_data, GUEST_STAGE_PTIMER_CVAL);
+ guest_run_stage(shared_data, GUEST_STAGE_PTIMER_TVAL);
+
+ GUEST_DONE();
+}
+
+static void *test_vcpu_run(void *arg)
+{
+ struct ucall uc;
+ struct test_vcpu *vcpu = arg;
+ struct kvm_vm *vm = vcpu->vm;
+ uint32_t vcpuid = vcpu->vcpuid;
+ struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[vcpuid];
+
+ vcpu_run(vm, vcpuid);
+
+ switch (get_ucall(vm, vcpuid, &uc)) {
+ case UCALL_SYNC:
+ case UCALL_DONE:
+ break;
+ case UCALL_ABORT:
+ sync_global_from_guest(vm, *shared_data);
+ TEST_FAIL("%s at %s:%ld\n\tvalues: %lu, %lu; %lu, vcpu: %u; stage: %u; iter: %u",
+ (const char *)uc.args[0], __FILE__, uc.args[1],
+ uc.args[2], uc.args[3], uc.args[4], vcpuid,
+ shared_data->guest_stage, shared_data->nr_iter);
+ break;
+ default:
+ TEST_FAIL("Unexpected guest exit\n");
+ }
+
+ return NULL;
+}
+
+static void test_run(struct kvm_vm *vm)
+{
+ int i, ret;
+
+ for (i = 0; i < test_args.nr_vcpus; i++) {
+ ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL,
+ test_vcpu_run, &test_vcpu[i]);
+ TEST_ASSERT(!ret, "Failed to create vCPU-%d pthread\n", i);
+ }
+
+ for (i = 0; i < test_args.nr_vcpus; i++)
+ pthread_join(test_vcpu[i].pt_vcpu_run, NULL);
+}
+
+static void test_init_timer_irq(struct kvm_vm *vm)
+{
+ /* Timer initid should be same for all the vCPUs, so query only vCPU-0 */
+ int vcpu0_fd = vcpu_get_fd(vm, 0);
+
+ kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
+ KVM_ARM_VCPU_TIMER_IRQ_PTIMER, &ptimer_irq, false);
+ kvm_device_access(vcpu0_fd, KVM_ARM_VCPU_TIMER_CTRL,
+ KVM_ARM_VCPU_TIMER_IRQ_VTIMER, &vtimer_irq, false);
+
+ sync_global_to_guest(vm, ptimer_irq);
+ sync_global_to_guest(vm, vtimer_irq);
+
+ pr_debug("ptimer_irq: %d; vtimer_irq: %d\n", ptimer_irq, vtimer_irq);
+}
+
+static struct kvm_vm *test_vm_create(void)
+{
+ struct kvm_vm *vm;
+ unsigned int i;
+ int nr_vcpus = test_args.nr_vcpus;
+
+ vm = vm_create_default_with_vcpus(nr_vcpus, 0, 0, guest_code, NULL);
+
+ vm_init_descriptor_tables(vm);
+ vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT, guest_irq_handler);
+
+ for (i = 0; i < nr_vcpus; i++) {
+ vcpu_init_descriptor_tables(vm, i);
+
+ test_vcpu[i].vcpuid = i;
+ test_vcpu[i].vm = vm;
+ }
+
+ ucall_init(vm, NULL);
+ test_init_timer_irq(vm);
+ vgic_v3_setup(vm, nr_vcpus, GICD_BASE_GPA, GICR_BASE_GPA);
+
+ /* Make all the test's cmdline args visible to the guest */
+ sync_global_to_guest(vm, test_args);
+
+ return vm;
+}
+
+static void test_print_help(char *name)
+{
+ pr_info("Usage: %s [-h] [-n nr_vcpus] [-i iterations] [-p timer_period_ms]\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-h: print this help screen\n");
+}
+
+static bool parse_args(int argc, char *argv[])
+{
+ int opt;
+
+ while ((opt = getopt(argc, argv, "hn:i:p:")) != -1) {
+ switch (opt) {
+ case 'n':
+ test_args.nr_vcpus = atoi(optarg);
+ if (test_args.nr_vcpus <= 0) {
+ pr_info("Positive value needed for -n\n");
+ goto err;
+ } else 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(optarg);
+ if (test_args.nr_iter <= 0) {
+ pr_info("Positive value needed for -i\n");
+ goto err;
+ }
+ break;
+ case 'p':
+ test_args.timer_period_ms = atoi(optarg);
+ if (test_args.timer_period_ms <= 0) {
+ pr_info("Positive value needed for -p\n");
+ goto err;
+ }
+ 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;
+
+ /* Tell stdout not to buffer its content */
+ setbuf(stdout, NULL);
+
+ if (!parse_args(argc, argv))
+ exit(KSFT_SKIP);
+
+ vm = test_vm_create();
+ test_run(vm);
+ kvm_vm_free(vm);
+
+ return 0;
+}
--
2.33.0.309.g3052b89438-goog