Re: [PATCH v4 15/18] KVM: arm64: selftests: Add arch_timer test
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From: Raghavendra Rao Ananta <hidden>
Date: 2021-09-09 18:03:44
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kvm, kvmarm, lkml
On Wed, Sep 8, 2021 at 10:51 PM Oliver Upton [off-list ref] wrote:
On Thu, Sep 09, 2021 at 01:38:15AM +0000, Raghavendra Rao Ananta wrote:quoted
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 <redacted> Reviewed-by: Andrew Jones <redacted> --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/arch_timer.c | 351 ++++++++++++++++++ 3 files changed, 353 insertions(+) create mode 100644 tools/testing/selftests/kvm/aarch64/arch_timer.cdiff --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_testdiff --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_testdiff --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..6141c387e6dc --- /dev/null +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c@@ -0,0 +1,351 @@ +// 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 VTIMER_IRQ 27 +#define PTIMER_IRQ 30I don't know if these are guaranteed, necessarily. Probably safest to determine the IRQ# from the KVM_ARM_VCPU_TIMER_IRQ_{P,V}TIMER vCPU device attributes. Either that or write these values to the attributes.
Correct me if I'm wrong, but aren't these the default INTIDs? And I believe KVM follows the same. Or are you just concerned since these are not defined as a part of UAPI, and have a potential to change? Regards, Raghavendra
quoted
+#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 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 = 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 = 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 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); + vm_vcpuid_map_init(vm); + vgic_v3_setup(vm, 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; +} -- 2.33.0.153.gba50c8fa24-goog
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