[PATCH kvm-unit-tests v1 5/6] s390x: smp: Create and use a non-waiting CPU restart

Eric Farman
2022-03-03T21:04:39Z

The kvm-unit-tests infrastructure for a CPU restart waits for the
SIGP RESTART to complete. In order to test the restart itself,
create a variation that does not wait, and test the state of the
CPU directly.

While here, add some better report prefixes/messages, to clarify
which condition is being examined (similar to test_stop_store_status()).

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
lib/s390x/smp.c | 22 ++++++++++++++++++++++
lib/s390x/smp.h | 1 +
s390x/smp.c | 18 +++++++++++++++---
3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
index 84e536e8..85b046a5 100644
--- a/lib/s390x/smp.c
+++ b/lib/s390x/smp.c
@@ -192,6 +192,28 @@ int smp_cpu_restart(uint16_t idx)
return rc;
}

+/*
+ * Functionally equivalent to smp_cpu_restart(), but without the
+ * elements that wait/serialize matters here in the test.
+ * Used to see if KVM itself is serialized correctly.
+ */
+int smp_cpu_restart_nowait(uint16_t idx)
+{
+ spin_lock(&lock);
+
+ /* Don't suppress a CC2 with sigp_retry() */
+ if (smp_sigp(idx, SIGP_RESTART, 0, NULL)) {
+ spin_unlock(&lock);
+ return -1;
+ }
+
+ cpus[idx].active = true;
+
+ spin_unlock(&lock);
+
+ return 0;
+}
+
int smp_cpu_start(uint16_t idx, struct psw psw)
{
int rc;
diff --git a/lib/s390x/smp.h b/lib/s390x/smp.h
index bae03dfd..24a0e2e0 100644
--- a/lib/s390x/smp.h
+++ b/lib/s390x/smp.h
@@ -42,6 +42,7 @@ uint16_t smp_cpu_addr(uint16_t idx);
bool smp_cpu_stopped(uint16_t idx);
bool smp_sense_running_status(uint16_t idx);
int smp_cpu_restart(uint16_t idx);
+int smp_cpu_restart_nowait(uint16_t idx);
int smp_cpu_start(uint16_t idx, struct psw psw);
int smp_cpu_stop(uint16_t idx);
int smp_cpu_stop_nowait(uint16_t idx);
diff --git a/s390x/smp.c b/s390x/smp.c
index 11c2c673..03160b80 100644
--- a/s390x/smp.c
+++ b/s390x/smp.c
@@ -55,23 +55,35 @@ static void test_restart(void)
struct cpu *cpu = smp_cpu_from_idx(1);
struct lowcore *lc = cpu->lowcore;

+ report_prefix_push("restart");
+ report_prefix_push("stopped");
+
lc->restart_new_psw.mask = extract_psw_mask();
lc->restart_new_psw.addr = (unsigned long)test_func;

/* Make sure cpu is stopped */
smp_cpu_stop(1);
set_flag(0);
- smp_cpu_restart(1);
+ smp_cpu_restart_nowait(1);
+ report(!smp_cpu_stopped(1), "cpu started");
wait_for_flag();
+ report_pass("test flag");
+
+ report_prefix_pop();
+ report_prefix_push("running");

/*
* Wait until cpu 1 has set the flag because it executed the
* restart function.
*/
set_flag(0);
- smp_cpu_restart(1);
+ smp_cpu_restart_nowait(1);
+ report(!smp_cpu_stopped(1), "cpu started");
wait_for_flag();
- report_pass("restart while running");
+ report_pass("test flag");
+
+ report_prefix_pop();
+ report_prefix_pop();
}

static void test_stop(void)
--
2.32.0