diff options
Diffstat (limited to 'tools/testing/selftests/kvm/rseq_test.c')
| -rw-r--r-- | tools/testing/selftests/kvm/rseq_test.c | 80 |
1 files changed, 37 insertions, 43 deletions
diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c index 2237d1aac801..fac248a43666 100644 --- a/tools/testing/selftests/kvm/rseq_test.c +++ b/tools/testing/selftests/kvm/rseq_test.c @@ -20,17 +20,7 @@ #include "processor.h" #include "test_util.h" -#define VCPU_ID 0 - -static __thread volatile struct rseq __rseq = { - .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, -}; - -/* - * Use an arbitrary, bogus signature for configuring rseq, this test does not - * actually enter an rseq critical section. - */ -#define RSEQ_SIG 0xdeadbeef +#include "../rseq/rseq.c" /* * Any bug related to task migration is likely to be timing-dependent; perform @@ -51,12 +41,16 @@ static void guest_code(void) GUEST_SYNC(0); } -static void sys_rseq(int flags) +/* + * We have to perform direct system call for getcpu() because it's + * not available until glic 2.29. + */ +static void sys_getcpu(unsigned *cpu) { int r; - r = syscall(__NR_rseq, &__rseq, sizeof(__rseq), flags, RSEQ_SIG); - TEST_ASSERT(!r, "rseq failed, errno = %d (%s)", errno, strerror(errno)); + r = syscall(__NR_getcpu, cpu, NULL, NULL); + TEST_ASSERT(!r, "getcpu failed, errno = %d (%s)", errno, strerror(errno)); } static int next_cpu(int cpu) @@ -103,7 +97,7 @@ static void *migration_worker(void *__rseq_tid) atomic_inc(&seq_cnt); /* - * Ensure the odd count is visible while sched_getcpu() isn't + * Ensure the odd count is visible while getcpu() isn't * stable, i.e. while changing affinity is in-progress. */ smp_wmb(); @@ -144,10 +138,10 @@ static void *migration_worker(void *__rseq_tid) * check completes. * * 3. To ensure the read-side makes efficient forward progress, - * e.g. if sched_getcpu() involves a syscall. Stalling the - * read-side means the test will spend more time waiting for - * sched_getcpu() to stabilize and less time trying to hit - * the timing-dependent bug. + * e.g. if getcpu() involves a syscall. Stalling the read-side + * means the test will spend more time waiting for getcpu() + * to stabilize and less time trying to hit the timing-dependent + * bug. * * Because any bug in this area is likely to be timing-dependent, * run with a range of delays at 1us intervals from 1us to 10us @@ -174,12 +168,11 @@ static void *migration_worker(void *__rseq_tid) return NULL; } -static int calc_min_max_cpu(void) +static void calc_min_max_cpu(void) { int i, cnt, nproc; - if (CPU_COUNT(&possible_mask) < 2) - return -EINVAL; + TEST_REQUIRE(CPU_COUNT(&possible_mask) >= 2); /* * CPU_SET doesn't provide a FOR_EACH helper, get the min/max CPU that @@ -201,13 +194,15 @@ static int calc_min_max_cpu(void) cnt++; } - return (cnt < 2) ? -EINVAL : 0; + __TEST_REQUIRE(cnt >= 2, + "Only one usable CPU, task migration not possible"); } int main(int argc, char *argv[]) { int r, i, snapshot; struct kvm_vm *vm; + struct kvm_vcpu *vcpu; u32 cpu, rseq_cpu; /* Tell stdout not to buffer its content */ @@ -217,34 +212,33 @@ int main(int argc, char *argv[]) TEST_ASSERT(!r, "sched_getaffinity failed, errno = %d (%s)", errno, strerror(errno)); - if (calc_min_max_cpu()) { - print_skip("Only one usable CPU, task migration not possible"); - exit(KSFT_SKIP); - } + calc_min_max_cpu(); - sys_rseq(0); + r = rseq_register_current_thread(); + TEST_ASSERT(!r, "rseq_register_current_thread failed, errno = %d (%s)", + errno, strerror(errno)); /* * Create and run a dummy VM that immediately exits to userspace via * GUEST_SYNC, while concurrently migrating the process by setting its * CPU affinity. */ - vm = vm_create_default(VCPU_ID, 0, guest_code); + vm = vm_create_with_one_vcpu(&vcpu, guest_code); ucall_init(vm, NULL); pthread_create(&migration_thread, NULL, migration_worker, (void *)(unsigned long)gettid()); for (i = 0; !done; i++) { - vcpu_run(vm, VCPU_ID); - TEST_ASSERT(get_ucall(vm, VCPU_ID, NULL) == UCALL_SYNC, + vcpu_run(vcpu); + TEST_ASSERT(get_ucall(vcpu, NULL) == UCALL_SYNC, "Guest failed?"); /* * Verify rseq's CPU matches sched's CPU. Ensure migration - * doesn't occur between sched_getcpu() and reading the rseq - * cpu_id by rereading both if the sequence count changes, or - * if the count is odd (migration in-progress). + * doesn't occur between getcpu() and reading the rseq cpu_id + * by rereading both if the sequence count changes, or if the + * count is odd (migration in-progress). */ do { /* @@ -254,13 +248,13 @@ int main(int argc, char *argv[]) snapshot = atomic_read(&seq_cnt) & ~1; /* - * Ensure reading sched_getcpu() and rseq.cpu_id - * complete in a single "no migration" window, i.e. are - * not reordered across the seq_cnt reads. + * Ensure calling getcpu() and reading rseq.cpu_id complete + * in a single "no migration" window, i.e. are not reordered + * across the seq_cnt reads. */ smp_rmb(); - cpu = sched_getcpu(); - rseq_cpu = READ_ONCE(__rseq.cpu_id); + sys_getcpu(&cpu); + rseq_cpu = rseq_current_cpu_raw(); smp_rmb(); } while (snapshot != atomic_read(&seq_cnt)); @@ -271,9 +265,9 @@ int main(int argc, char *argv[]) /* * Sanity check that the test was able to enter the guest a reasonable * number of times, e.g. didn't get stalled too often/long waiting for - * sched_getcpu() to stabilize. A 2:1 migration:KVM_RUN ratio is a - * fairly conservative ratio on x86-64, which can do _more_ KVM_RUNs - * than migrations given the 1us+ delay in the migration task. + * getcpu() to stabilize. A 2:1 migration:KVM_RUN ratio is a fairly + * conservative ratio on x86-64, which can do _more_ KVM_RUNs than + * migrations given the 1us+ delay in the migration task. */ TEST_ASSERT(i > (NR_TASK_MIGRATIONS / 2), "Only performed %d KVM_RUNs, task stalled too much?\n", i); @@ -282,7 +276,7 @@ int main(int argc, char *argv[]) kvm_vm_free(vm); - sys_rseq(RSEQ_FLAG_UNREGISTER); + rseq_unregister_current_thread(); return 0; } |