[kvm-unit-tests,GIT,PULL,05/27] s390x: smp: Create and use a non-waiting CPU restart

Commit Message

Claudio Imbrenda April 1, 2022, 11:15 a.m. UTC

From: Eric Farman <[e-mail]>

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 <[e-mail]>
Reviewed-by: Janosch Frank <[e-mail]>
Reviewed-by: Nico Boehr <[e-mail]>
Signed-off-by: Claudio Imbrenda <[e-mail]>
---
 lib/s390x/smp.h |  1 +
 lib/s390x/smp.c | 24 ++++++++++++++++++++++++
 s390x/smp.c     | 21 ++++++++++++++++++---
 3 files changed, 43 insertions(+), 3 deletions(-)

Patch

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/lib/s390x/smp.c b/lib/s390x/smp.c
index b69c0e09..5be29d36 100644
--- a/lib/s390x/smp.c
+++ b/lib/s390x/smp.c
@@ -194,6 +194,30 @@  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)
+{
+	check_idx(idx);
+
+	spin_lock(&lock);
+
+	/* Don't suppress a CC2 with sigp_retry() */
+	if (sigp(cpus[idx].addr, 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/s390x/smp.c b/s390x/smp.c
index f70a9c54..913da155 100644
--- a/s390x/smp.c
+++ b/s390x/smp.c
@@ -54,6 +54,10 @@  static void test_restart(void)
 {
 	struct cpu *cpu = smp_cpu_from_idx(1);
 	struct lowcore *lc = cpu->lowcore;
+	int rc;
+
+	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;
@@ -61,17 +65,28 @@  static void test_restart(void)
 	/* Make sure cpu is stopped */
 	smp_cpu_stop(1);
 	set_flag(0);
-	smp_cpu_restart(1);
+	rc = smp_cpu_restart_nowait(1);
+	report(!rc, "return code");
+	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);
+	rc = smp_cpu_restart_nowait(1);
+	report(!rc, "return code");
+	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)