| Message ID | 20210909013818.1191270-17-rananta@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: selftests: Introduce arch_timer selftest | expand |
On Thu, Sep 09, 2021 at 01:38:16AM +0000, Raghavendra Rao Ananta wrote: > Since the timer stack (hardware and KVM) is per-CPU, there > are potential chances for races to occur when the scheduler > decides to migrate a vCPU thread to a different physical CPU. > Hence, include an option to stress-test this part as well by > forcing the vCPUs to migrate across physical CPUs in the > system at a particular rate. > > Originally, the bug for the fix with commit 3134cc8beb69d0d > ("KVM: arm64: vgic: Resample HW pending state on deactivation") > was discovered using arch_timer test with vCPU migrations and > can be easily reproduced. > > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> > --- > .../selftests/kvm/aarch64/arch_timer.c | 113 +++++++++++++++++- > 1 file changed, 112 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c > index 6141c387e6dc..aac7bcea4352 100644 > --- a/tools/testing/selftests/kvm/aarch64/arch_timer.c > +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c > @@ -14,6 +14,8 @@ > * > * 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. > */ > @@ -24,6 +26,8 @@ > #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" > @@ -36,17 +40,20 @@ > #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) > @@ -81,6 +88,9 @@ struct test_vcpu { > static struct test_vcpu test_vcpu[KVM_MAX_VCPUS]; > static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS]; > > +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) > { > @@ -216,6 +226,11 @@ static void *test_vcpu_run(void *arg) > > vcpu_run(vm, vcpuid); > > + /* Currently, any exit from guest is an indication of completion */ > + pthread_mutex_lock(&vcpu_done_map_lock); > + set_bit(vcpuid, vcpu_done_map); > + pthread_mutex_unlock(&vcpu_done_map_lock); > + > switch (get_ucall(vm, vcpuid, &uc)) { > case UCALL_SYNC: > case UCALL_DONE: > @@ -234,9 +249,76 @@ static void *test_vcpu_run(void *arg) > 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; > +} Missing blank line here. > +static int test_migrate_vcpu(struct test_vcpu *vcpu) > +{ > + 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->vcpuid, new_pcpu); > + > + ret = pthread_setaffinity_np(vcpu->pt_vcpu_run, > + 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->vcpuid, new_pcpu, ret); > + > + return ret; > +} Missing blank line here. > +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(&test_vcpu[i]); > + } > + } while (test_args.nr_vcpus != n_done); > + > + return NULL; > +} > + > static void test_run(struct kvm_vm *vm) > { > int i, ret; > + pthread_t pt_vcpu_migration; > + > + pthread_mutex_init(&vcpu_done_map_lock, NULL); > + vcpu_done_map = bitmap_alloc(test_args.nr_vcpus); > + TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n"); > > for (i = 0; i < test_args.nr_vcpus; i++) { > ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL, > @@ -244,8 +326,23 @@ static void test_run(struct kvm_vm *vm) > 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(test_vcpu[i].pt_vcpu_run, NULL); > + > + if (test_args.migration_freq_ms) > + pthread_join(pt_vcpu_migration, NULL); > + > + bitmap_free(vcpu_done_map); > } > > static struct kvm_vm *test_vm_create(void) > @@ -286,6 +383,8 @@ static void test_print_help(char *name) > 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"); > } > > @@ -293,7 +392,7 @@ static bool parse_args(int argc, char *argv[]) > { > int opt; > > - while ((opt = getopt(argc, argv, "hn:i:p:")) != -1) { > + while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) { > switch (opt) { > case 'n': > test_args.nr_vcpus = atoi(optarg); > @@ -320,6 +419,13 @@ static bool parse_args(int argc, char *argv[]) > goto err; > } > break; > + case 'm': > + test_args.migration_freq_ms = atoi(optarg); > + if (test_args.migration_freq_ms < 0) { > + pr_info("0 or positive value needed for -m\n"); > + goto err; > + } > + break; > case 'h': > default: > goto err; > @@ -343,6 +449,11 @@ int main(int argc, char *argv[]) > if (!parse_args(argc, argv)) > exit(KSFT_SKIP); > > + if (get_nprocs() < 2) { Even though the chance of being on a uniprocessor is low and the migration test is now on by default, we could still do if (test_args.migration_freq_ms && get_nprocs() < 2) since that's why the skip message says it needs two cpus. > + print_skip("At least two physical CPUs needed for vCPU migration"); > + exit(KSFT_SKIP); > + } > + > vm = test_vm_create(); > test_run(vm); > kvm_vm_free(vm); > -- > 2.33.0.153.gba50c8fa24-goog > Reviewed-by: Andrew Jones <drjones@redhat.com> Thanks, drew
On Thu, Sep 9, 2021 at 6:45 AM Andrew Jones <drjones@redhat.com> wrote: > > On Thu, Sep 09, 2021 at 01:38:16AM +0000, Raghavendra Rao Ananta wrote: > > Since the timer stack (hardware and KVM) is per-CPU, there > > are potential chances for races to occur when the scheduler > > decides to migrate a vCPU thread to a different physical CPU. > > Hence, include an option to stress-test this part as well by > > forcing the vCPUs to migrate across physical CPUs in the > > system at a particular rate. > > > > Originally, the bug for the fix with commit 3134cc8beb69d0d > > ("KVM: arm64: vgic: Resample HW pending state on deactivation") > > was discovered using arch_timer test with vCPU migrations and > > can be easily reproduced. > > > > Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> > > --- > > .../selftests/kvm/aarch64/arch_timer.c | 113 +++++++++++++++++- > > 1 file changed, 112 insertions(+), 1 deletion(-) > > > > diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c > > index 6141c387e6dc..aac7bcea4352 100644 > > --- a/tools/testing/selftests/kvm/aarch64/arch_timer.c > > +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c > > @@ -14,6 +14,8 @@ > > * > > * 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. > > */ > > @@ -24,6 +26,8 @@ > > #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" > > @@ -36,17 +40,20 @@ > > #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) > > @@ -81,6 +88,9 @@ struct test_vcpu { > > static struct test_vcpu test_vcpu[KVM_MAX_VCPUS]; > > static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS]; > > > > +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) > > { > > @@ -216,6 +226,11 @@ static void *test_vcpu_run(void *arg) > > > > vcpu_run(vm, vcpuid); > > > > + /* Currently, any exit from guest is an indication of completion */ > > + pthread_mutex_lock(&vcpu_done_map_lock); > > + set_bit(vcpuid, vcpu_done_map); > > + pthread_mutex_unlock(&vcpu_done_map_lock); > > + > > switch (get_ucall(vm, vcpuid, &uc)) { > > case UCALL_SYNC: > > case UCALL_DONE: > > @@ -234,9 +249,76 @@ static void *test_vcpu_run(void *arg) > > 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; > > +} > > Missing blank line here. > > > +static int test_migrate_vcpu(struct test_vcpu *vcpu) > > +{ > > + 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->vcpuid, new_pcpu); > > + > > + ret = pthread_setaffinity_np(vcpu->pt_vcpu_run, > > + 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->vcpuid, new_pcpu, ret); > > + > > + return ret; > > +} > > Missing blank line here. > > > +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(&test_vcpu[i]); > > + } > > + } while (test_args.nr_vcpus != n_done); > > + > > + return NULL; > > +} > > + > > static void test_run(struct kvm_vm *vm) > > { > > int i, ret; > > + pthread_t pt_vcpu_migration; > > + > > + pthread_mutex_init(&vcpu_done_map_lock, NULL); > > + vcpu_done_map = bitmap_alloc(test_args.nr_vcpus); > > + TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n"); > > > > for (i = 0; i < test_args.nr_vcpus; i++) { > > ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL, > > @@ -244,8 +326,23 @@ static void test_run(struct kvm_vm *vm) > > 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(test_vcpu[i].pt_vcpu_run, NULL); > > + > > + if (test_args.migration_freq_ms) > > + pthread_join(pt_vcpu_migration, NULL); > > + > > + bitmap_free(vcpu_done_map); > > } > > > > static struct kvm_vm *test_vm_create(void) > > @@ -286,6 +383,8 @@ static void test_print_help(char *name) > > 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"); > > } > > > > @@ -293,7 +392,7 @@ static bool parse_args(int argc, char *argv[]) > > { > > int opt; > > > > - while ((opt = getopt(argc, argv, "hn:i:p:")) != -1) { > > + while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) { > > switch (opt) { > > case 'n': > > test_args.nr_vcpus = atoi(optarg); > > @@ -320,6 +419,13 @@ static bool parse_args(int argc, char *argv[]) > > goto err; > > } > > break; > > + case 'm': > > + test_args.migration_freq_ms = atoi(optarg); > > + if (test_args.migration_freq_ms < 0) { > > + pr_info("0 or positive value needed for -m\n"); > > + goto err; > > + } > > + break; > > case 'h': > > default: > > goto err; > > @@ -343,6 +449,11 @@ int main(int argc, char *argv[]) > > if (!parse_args(argc, argv)) > > exit(KSFT_SKIP); > > > > + if (get_nprocs() < 2) { > > Even though the chance of being on a uniprocessor is low and the migration > test is now on by default, we could still do > > if (test_args.migration_freq_ms && get_nprocs() < 2) > huh, I had the check earlier; must have dropped it somewhere. Will place it back. And I'll fix all the blank line comments. Regards, Raghavendra > since that's why the skip message says it needs two cpus. > > > + print_skip("At least two physical CPUs needed for vCPU migration"); > > + exit(KSFT_SKIP); > > + } > > + > > vm = test_vm_create(); > > test_run(vm); > > kvm_vm_free(vm); > > -- > > 2.33.0.153.gba50c8fa24-goog > > > > Reviewed-by: Andrew Jones <drjones@redhat.com> > > Thanks, > drew >
diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c index 6141c387e6dc..aac7bcea4352 100644 --- a/tools/testing/selftests/kvm/aarch64/arch_timer.c +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c @@ -14,6 +14,8 @@ * * 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. */ @@ -24,6 +26,8 @@ #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" @@ -36,17 +40,20 @@ #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) @@ -81,6 +88,9 @@ struct test_vcpu { static struct test_vcpu test_vcpu[KVM_MAX_VCPUS]; static struct test_vcpu_shared_data vcpu_shared_data[KVM_MAX_VCPUS]; +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) { @@ -216,6 +226,11 @@ static void *test_vcpu_run(void *arg) vcpu_run(vm, vcpuid); + /* Currently, any exit from guest is an indication of completion */ + pthread_mutex_lock(&vcpu_done_map_lock); + set_bit(vcpuid, vcpu_done_map); + pthread_mutex_unlock(&vcpu_done_map_lock); + switch (get_ucall(vm, vcpuid, &uc)) { case UCALL_SYNC: case UCALL_DONE: @@ -234,9 +249,76 @@ static void *test_vcpu_run(void *arg) 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(struct test_vcpu *vcpu) +{ + 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->vcpuid, new_pcpu); + + ret = pthread_setaffinity_np(vcpu->pt_vcpu_run, + 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->vcpuid, 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(&test_vcpu[i]); + } + } while (test_args.nr_vcpus != n_done); + + return NULL; +} + static void test_run(struct kvm_vm *vm) { int i, ret; + pthread_t pt_vcpu_migration; + + pthread_mutex_init(&vcpu_done_map_lock, NULL); + vcpu_done_map = bitmap_alloc(test_args.nr_vcpus); + TEST_ASSERT(vcpu_done_map, "Failed to allocate vcpu done bitmap\n"); for (i = 0; i < test_args.nr_vcpus; i++) { ret = pthread_create(&test_vcpu[i].pt_vcpu_run, NULL, @@ -244,8 +326,23 @@ static void test_run(struct kvm_vm *vm) 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(test_vcpu[i].pt_vcpu_run, NULL); + + if (test_args.migration_freq_ms) + pthread_join(pt_vcpu_migration, NULL); + + bitmap_free(vcpu_done_map); } static struct kvm_vm *test_vm_create(void) @@ -286,6 +383,8 @@ static void test_print_help(char *name) 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"); } @@ -293,7 +392,7 @@ static bool parse_args(int argc, char *argv[]) { int opt; - while ((opt = getopt(argc, argv, "hn:i:p:")) != -1) { + while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) { switch (opt) { case 'n': test_args.nr_vcpus = atoi(optarg); @@ -320,6 +419,13 @@ static bool parse_args(int argc, char *argv[]) goto err; } break; + case 'm': + test_args.migration_freq_ms = atoi(optarg); + if (test_args.migration_freq_ms < 0) { + pr_info("0 or positive value needed for -m\n"); + goto err; + } + break; case 'h': default: goto err; @@ -343,6 +449,11 @@ int main(int argc, char *argv[]) if (!parse_args(argc, argv)) exit(KSFT_SKIP); + if (get_nprocs() < 2) { + print_skip("At least two physical CPUs needed for vCPU migration"); + exit(KSFT_SKIP); + } + vm = test_vm_create(); test_run(vm); kvm_vm_free(vm);
Since the timer stack (hardware and KVM) is per-CPU, there are potential chances for races to occur when the scheduler decides to migrate a vCPU thread to a different physical CPU. Hence, include an option to stress-test this part as well by forcing the vCPUs to migrate across physical CPUs in the system at a particular rate. Originally, the bug for the fix with commit 3134cc8beb69d0d ("KVM: arm64: vgic: Resample HW pending state on deactivation") was discovered using arch_timer test with vCPU migrations and can be easily reproduced. Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> --- .../selftests/kvm/aarch64/arch_timer.c | 113 +++++++++++++++++- 1 file changed, 112 insertions(+), 1 deletion(-)