Add a KVM selftest to validate the Sstc timer functionality.
The test was ported from arm64 arch_timer test.
Signed-off-by: Haibo Xu <haibo1.xu@xxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/riscv/processor.h | 25 ++
.../selftests/kvm/include/riscv/sstc_timer.h | 70 ++++
.../selftests/kvm/lib/riscv/processor.c | 9 +
.../testing/selftests/kvm/riscv/sstc_timer.c | 382 ++++++++++++++++++
5 files changed, 487 insertions(+)
create mode 100644 tools/testing/selftests/kvm/include/riscv/sstc_timer.h
create mode 100644 tools/testing/selftests/kvm/riscv/sstc_timer.c
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 70f3a5ba991e..92b9a26b515d 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -175,6 +175,7 @@ TEST_GEN_PROGS_s390x += rseq_test
TEST_GEN_PROGS_s390x += set_memory_region_test
TEST_GEN_PROGS_s390x += kvm_binary_stats_test
+TEST_GEN_PROGS_riscv += riscv/sstc_timer
TEST_GEN_PROGS_riscv += demand_paging_test
TEST_GEN_PROGS_riscv += dirty_log_test
TEST_GEN_PROGS_riscv += kvm_create_max_vcpus
diff --git a/tools/testing/selftests/kvm/include/riscv/processor.h b/tools/testing/selftests/kvm/include/riscv/processor.h
index ca53570ce6de..4846b4598bd9 100644
--- a/tools/testing/selftests/kvm/include/riscv/processor.h
+++ b/tools/testing/selftests/kvm/include/riscv/processor.h
@@ -39,6 +39,11 @@ static inline uint64_t __kvm_reg_id(uint64_t type, uint64_t idx,
KVM_REG_RISCV_TIMER_REG(name), \
KVM_REG_SIZE_U64)
+#define RISCV_ISA_EXT_REG(idx) __kvm_reg_id(KVM_REG_RISCV_ISA_EXT, \
+ idx, KVM_REG_SIZE_ULONG)
+
+bool vcpu_has_ext(struct kvm_vcpu *vcpu, int ext);
+
struct ex_regs {
unsigned long ra;
unsigned long sp;
@@ -87,6 +92,16 @@ typedef void(*handler_fn)(struct ex_regs *);
void vm_install_exception_handler(struct kvm_vm *vm, int ec, handler_fn handler);
void vm_install_interrupt_handler(struct kvm_vm *vm, handler_fn handler);
+static inline void cpu_relax(void)
+{
+#ifdef __riscv_zihintpause
+ asm volatile("pause" ::: "memory");
+#else
+ /* Encoding of the pause instruction */
+ asm volatile(".4byte 0x100000F" ::: "memory");
+#endif
+}
+
/* L3 index Bit[47:39] */
#define PGTBL_L3_INDEX_MASK 0x0000FF8000000000ULL
#define PGTBL_L3_INDEX_SHIFT 39
@@ -165,6 +180,16 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
unsigned long arg3, unsigned long arg4,
unsigned long arg5);
+static inline void local_irq_enable(void)
+{
+ csr_set(CSR_SSTATUS, SR_SIE);
+}
+
+static inline void local_irq_disable(void)
+{
+ csr_clear(CSR_SSTATUS, SR_SIE);
+}
+
uint32_t guest_get_vcpuid(void);
#endif /* SELFTEST_KVM_PROCESSOR_H */
diff --git a/tools/testing/selftests/kvm/include/riscv/sstc_timer.h b/tools/testing/selftests/kvm/include/riscv/sstc_timer.h
new file mode 100644
index 000000000000..7c4a4b26faa0
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/riscv/sstc_timer.h
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RISC-V SSTC Timer specific interface
+ *
+ * Copyright (c) 2023 Intel Corporation
+ */
+
+#ifndef SELFTEST_KVM_SSTC_TIMER_H
+#define SELFTEST_KVM_SSTC_TIMER_H
+
+#include "processor.h"
+
+static unsigned long timer_freq;
+
+#define msec_to_cycles(msec) \
+ ((timer_freq) * (uint64_t)(msec) / 1000)
+
+#define usec_to_cycles(usec) \
+ ((timer_freq) * (uint64_t)(usec) / 1000000)
+
+#define cycles_to_usec(cycles) \
+ ((uint64_t)(cycles) * 1000000 / (timer_freq))
+
+static inline uint64_t timer_get_cntct(void)
+{
+ return csr_read(CSR_TIME);
+}
+
+static inline void timer_set_cval(uint64_t cval)
+{
+ csr_write(CSR_STIMECMP, cval);
+}
+
+static inline uint64_t timer_get_cval(void)
+{
+ return csr_read(CSR_STIMECMP);
+}
+
+static inline void timer_irq_enable(void)
+{
+ csr_set(CSR_SIE, IE_TIE);
+}
+
+static inline void timer_irq_disable(void)
+{
+ csr_clear(CSR_SIE, IE_TIE);
+}
+
+static inline void timer_set_next_cval_ms(uint32_t msec)
+{
+ uint64_t now_ct = timer_get_cntct();
+ uint64_t next_ct = now_ct + msec_to_cycles(msec);
+
+ timer_set_cval(next_ct);
+}
+
+static inline void __delay(uint64_t cycles)
+{
+ uint64_t start = timer_get_cntct();
+
+ while ((timer_get_cntct() - start) < cycles)
+ cpu_relax();
+}
+
+static inline void udelay(unsigned long usec)
+{
+ __delay(usec_to_cycles(usec));
+}
+
+#endif /* SELFTEST_KVM_SSTC_TIMER_H */
diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
index b8ad3e69a697..f6ce3d61738f 100644
--- a/tools/testing/selftests/kvm/lib/riscv/processor.c
+++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
@@ -15,6 +15,15 @@
static vm_vaddr_t exception_handlers;
+bool vcpu_has_ext(struct kvm_vcpu *vcpu, int ext)
+{
+ unsigned long value = 0;
+
+ vcpu_get_reg(vcpu, RISCV_ISA_EXT_REG(ext), &value);
+
+ return !!value;
+}
+
static uint64_t page_align(struct kvm_vm *vm, uint64_t v)
{
return (v + vm->page_size) & ~(vm->page_size - 1);
diff --git a/tools/testing/selftests/kvm/riscv/sstc_timer.c b/tools/testing/selftests/kvm/riscv/sstc_timer.c
new file mode 100644
index 000000000000..867bd686a9c5
--- /dev/null
+++ b/tools/testing/selftests/kvm/riscv/sstc_timer.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sstc_timer.c - Tests the riscv64 sstc timer IRQ functionality
+ *
+ * The test validates the sstc timer IRQs using vstimecmp 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).
+ * 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.
+ * Copyright (c) 2023, Intel Corporation.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <pthread.h>
+#include <linux/kvm.h>
+#include <linux/sizes.h>
+#include <linux/bitmap.h>
+#include <sys/sysinfo.h>
+
+#include "kvm_util.h"
+#include "processor.h"
+#include "sstc_timer.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
+#define TIMER_TEST_MIGRATION_FREQ_MS 2
+
+struct test_args {
+ int nr_vcpus;
+ int nr_iter;
+ int timer_period_ms;
+ int migration_freq_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,
+ .migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
+};
+
+#define msecs_to_usecs(msec) ((msec) * 1000LL)
+
+/* Shared variables between host and guest */
+struct test_vcpu_shared_data {
+ int nr_iter;
+ uint64_t xcnt;
+};
+
+static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+static pthread_t pt_vcpu_run[KVM_MAX_VCPUS];
+static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS];
+
+static int timer_irq = IRQ_S_TIMER;
+
+static unsigned long *vcpu_done_map;
+static pthread_mutex_t vcpu_done_map_lock;
+
+static void
+guest_configure_timer_action(struct test_vcpu_shared_data *shared_data)
+{
+ timer_set_next_cval_ms(test_args.timer_period_ms);
+ shared_data->xcnt = timer_get_cntct();
+ timer_irq_enable();
+}
+
+static void guest_validate_irq(unsigned int intid,
+ struct test_vcpu_shared_data *shared_data)
+{
+ uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
+
+ timer_irq_disable();
+ xcnt = timer_get_cntct();
+ cval = timer_get_cval();
+
+ 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);
+
+ GUEST_ASSERT_3(xcnt >= cval, xcnt, cval, xcnt_diff_us);
+
+ WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
+}
+
+static void guest_irq_handler(struct ex_regs *regs)
+{
+ unsigned int intid = regs->cause & ~CAUSE_IRQ_FLAG;
+ uint32_t cpu = guest_get_vcpuid();
+ struct test_vcpu_shared_data *shared_data = &vcpu_shared_data[cpu];
+
+ guest_validate_irq(intid, shared_data);
+}
+
+static void guest_run(struct test_vcpu_shared_data *shared_data)
+{
+ uint32_t irq_iter, config_iter;
+
+ 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();
+ timer_irq_disable();
+ local_irq_enable();
+
+ guest_run(shared_data);
+
+ GUEST_DONE();
+}
+
+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);
+ REPORT_GUEST_ASSERT_N(uc, "values: %lu, %lu, %lu; vcpu: %u; iter: %u",
+ GUEST_ASSERT_ARG(uc, 0),
+ GUEST_ASSERT_ARG(uc, 1),
+ GUEST_ASSERT_ARG(uc, 2),
+ vcpu_idx,
+ shared_data->nr_iter);
+ break;
+ default:
+ TEST_FAIL("Unexpected guest exit\n");
+ }
+
+ 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\n",
+ 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\n");
+
+ 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\n", 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\n");
+ }
+
+ 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_init_timer_freq(struct kvm_vm *vm)
+{
+ /* Timer frequency should be same for all the vCPUs, so query only vCPU-0 */
+ vcpu_get_reg(vcpus[0], RISCV_TIMER_REG(frequency), &timer_freq);
+ sync_global_to_guest(vm, timer_freq);
+
+ pr_debug("timer_freq: %lu\n", timer_freq);
+}
+
+static struct kvm_vm *test_vm_create(void)
+{
+ struct kvm_vm *vm;
+ int nr_vcpus = test_args.nr_vcpus;
+
+ vm = vm_create_with_vcpus(nr_vcpus, guest_code, vcpus);
+ __TEST_REQUIRE(vcpu_has_ext(vcpus[0], KVM_RISCV_ISA_EXT_SSTC),
+ "SSTC not available, skipping test\n");
+
+ vm_init_trap_vector_tables(vm);
+ vm_install_interrupt_handler(vm, guest_irq_handler);
+
+ for (int i = 0; i < nr_vcpus; i++)
+ vcpu_init_trap_vector_tables(vcpus[i]);
+
+ test_init_timer_freq(vm);
+
+ /* Make all the test's cmdline args visible to the guest */
+ sync_global_to_guest(vm, test_args);
+
+ return vm;
+}
+
+static void test_vm_cleanup(struct kvm_vm *vm)
+{
+ kvm_vm_free(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-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-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:")) != -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 '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;
+}
--
2.34.1
