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David Alan Gilbert" , peterx@redhat.com, Vitaly Kuznetsov Subject: [PATCH RFC 15/15] KVM: selftests: Test dirty ring waitqueue Date: Fri, 29 Nov 2019 16:35:05 -0500 Message-Id: <20191129213505.18472-16-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191129213505.18472-1-peterx@redhat.com> References: <20191129213505.18472-1-peterx@redhat.com> MIME-Version: 1.0 X-MC-Unique: H8M-nMrMOTyf-L6sRIuU_g-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This is a bit tricky, but should still be reasonable. Firstly we introduce a totally new dirty log test type, because we need to force vcpu to go into a blocked state by dead loop on vcpu_run even if it wants to quit to userspace. Here the tricky part is we need to read the procfs to make sure the vcpu thread is TASK_UNINTERRUPTIBLE. After that, we reset the ring and the reset should kick the vcpu again by moving out of that state. Signed-off-by: Peter Xu --- tools/testing/selftests/kvm/dirty_log_test.c | 101 +++++++++++++++++++ 1 file changed, 101 insertions(+) diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/s= elftests/kvm/dirty_log_test.c index c9db136a1f12..41bc015131e1 100644 --- a/tools/testing/selftests/kvm/dirty_log_test.c +++ b/tools/testing/selftests/kvm/dirty_log_test.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -151,12 +152,16 @@ enum log_mode_t { =09/* Use dirty ring for logging */ =09LOG_MODE_DIRTY_RING =3D 2, =20 +=09/* Dirty ring test but tailored for the waitqueue */ +=09LOG_MODE_DIRTY_RING_WP =3D 3, + =09LOG_MODE_NUM, }; =20 /* Mode of logging. Default is LOG_MODE_DIRTY_LOG */ static enum log_mode_t host_log_mode; pthread_t vcpu_thread; +pid_t vcpu_thread_tid; static uint32_t test_dirty_ring_count =3D TEST_DIRTY_RING_COUNT; =20 /* Only way to pass this to the signal handler */ @@ -221,6 +226,18 @@ static void dirty_ring_create_vm_done(struct kvm_vm *v= m) =09=09=09 sizeof(struct kvm_dirty_gfn)); } =20 +static void dirty_ring_wq_create_vm_done(struct kvm_vm *vm) +{ +=09/* +=09 * Force to use a relatively small ring size, so easier to get +=09 * full. Better bigger than PML size, hence 1024. +=09 */ +=09test_dirty_ring_count =3D 1024; +=09DEBUG("Forcing ring size: %u\n", test_dirty_ring_count); +=09vm_enable_dirty_ring(vm, test_dirty_ring_count * +=09=09=09 sizeof(struct kvm_dirty_gfn)); +} + static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns, =09=09=09=09 struct kvm_dirty_ring_indexes *indexes, =09=09=09=09 int slot, void *bitmap, @@ -295,6 +312,81 @@ static void dirty_ring_collect_dirty_pages(struct kvm_= vm *vm, int slot, =09DEBUG("Iteration %ld collected %u pages\n", iteration, count); } =20 +/* + * Return 'D' for uninterruptible, 'R' for running, 'S' for + * interruptible, etc. + */ +static char read_tid_status_char(unsigned int tid) +{ +=09int fd, ret, line =3D 0; +=09char buf[128], *c; + +=09snprintf(buf, sizeof(buf) - 1, "/proc/%u/status", tid); +=09fd =3D open(buf, O_RDONLY); +=09TEST_ASSERT(fd >=3D 0, "open status file failed: %s", buf); +=09ret =3D read(fd, buf, sizeof(buf) - 1); +=09TEST_ASSERT(ret > 0, "read status file failed: %d, %d", ret, errno); +=09close(fd); + +=09/* Skip 2 lines */ +=09for (c =3D buf; c < buf + sizeof(buf) && line < 2; c++) { +=09=09if (*c =3D=3D '\n') { +=09=09=09line++; +=09=09=09continue; +=09=09} +=09} + +=09/* Skip "Status: " */ +=09while (*c !=3D ':') c++; +=09c++; +=09while (*c =3D=3D ' ') c++; +=09c++; + +=09return *c; +} + +static void dirty_ring_wq_collect_dirty_pages(struct kvm_vm *vm, int slot, +=09=09=09=09=09 void *bitmap, uint32_t num_pages) +{ +=09uint32_t count =3D test_dirty_ring_count; +=09struct kvm_run *state =3D vcpu_state(vm, VCPU_ID); +=09struct kvm_dirty_ring_indexes *indexes =3D &state->vcpu_ring_indexes; +=09uint32_t avail; + +=09while (count--) { +=09=09/* +=09=09 * Force vcpu to run enough time to make sure we +=09=09 * trigger the ring full case +=09=09 */ +=09=09sem_post(&dirty_ring_vcpu_cont); +=09} + +=09/* Make sure it's stuck */ +=09TEST_ASSERT(vcpu_thread_tid, "TID not inited"); + /* +=09 * Wait for /proc/pid/status "Status:" changes to "D". "D" +=09 * stands for "D (disk sleep)", TASK_UNINTERRUPTIBLE +=09 */ +=09while (read_tid_status_char(vcpu_thread_tid) !=3D 'D') { +=09=09usleep(1000); +=09} +=09DEBUG("Now VCPU thread dirty ring full\n"); + +=09avail =3D READ_ONCE(indexes->avail_index); +=09/* Assuming we've consumed all */ +=09WRITE_ONCE(indexes->fetch_index, avail); + +=09kvm_vm_reset_dirty_ring(vm); + +=09/* Wait for it to be awake */ +=09while (read_tid_status_char(vcpu_thread_tid) =3D=3D 'D') { +=09=09usleep(1000); +=09} +=09DEBUG("VCPU Thread is successfully waked up\n"); + +=09exit(0); +} + static void dirty_ring_after_vcpu_run(struct kvm_vm *vm, int ret, int err) { =09struct kvm_run *run =3D vcpu_state(vm, VCPU_ID); @@ -353,6 +445,12 @@ struct log_mode { =09=09.before_vcpu_join =3D dirty_ring_before_vcpu_join, =09=09.after_vcpu_run =3D dirty_ring_after_vcpu_run, =09}, +=09{ +=09=09.name =3D "dirty-ring-wait-queue", +=09=09.create_vm_done =3D dirty_ring_wq_create_vm_done, +=09=09.collect_dirty_pages =3D dirty_ring_wq_collect_dirty_pages, +=09=09.after_vcpu_run =3D dirty_ring_after_vcpu_run, +=09}, }; =20 /* @@ -422,6 +520,9 @@ static void *vcpu_worker(void *data) =09uint64_t *guest_array; =09struct sigaction sigact; =20 +=09vcpu_thread_tid =3D syscall(SYS_gettid); +=09printf("VCPU Thread ID: %u\n", vcpu_thread_tid); + =09current_vm =3D vm; =09memset(&sigact, 0, sizeof(sigact)); =09sigact.sa_handler =3D vcpu_sig_handler; --=20 2.21.0