[kvm-unit-tests PATCH v6 07/10] s390x: css: msch, enable test

Pierre Morel
2020-04-24T10:46:03Z

A second step when testing the channel subsystem is to prepare a channel
for use.
This includes:
- Get the current SubCHannel Information Block (SCHIB) using STSCH
- Update it in memory to set the ENABLE bit
- Tell the CSS that the SCHIB has been modified using MSCH
- Get the SCHIB from the CSS again to verify that the subchannel is
enabled.

This tests the MSCH instruction to enable a channel succesfuly.
This is NOT a routine to really enable the channel, no retry is done,
in case of error, a report is made.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
s390x/css.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/s390x/css.c b/s390x/css.c
index cc97e79..fa068bf 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -68,11 +68,59 @@ out:
scn, scn_found, dev_found);
}

+static void test_enable(void)
+{
+ struct pmcw *pmcw = &schib.pmcw;
+ int cc;
+
+ if (!test_device_sid) {
+ report_skip("No device");
+ return;
+ }
+ /* Read the SCHIB for this subchannel */
+ cc = stsch(test_device_sid, &schib);
+ if (cc) {
+ report(0, "stsch cc=%d", cc);
+ return;
+ }
+
+ /* Update the SCHIB to enable the channel */
+ pmcw->flags |= PMCW_ENABLE;
+
+ /* Tell the CSS we want to modify the subchannel */
+ cc = msch(test_device_sid, &schib);
+ if (cc) {
+ /*
+ * If the subchannel is status pending or
+ * if a function is in progress,
+ * we consider both cases as errors.
+ */
+ report(0, "msch cc=%d", cc);
+ return;
+ }
+
+ /*
+ * Read the SCHIB again to verify the enablement
+ */
+ cc = stsch(test_device_sid, &schib);
+ if (cc) {
+ report(0, "stsch cc=%d", cc);
+ return;
+ }
+
+ if (!(pmcw->flags & PMCW_ENABLE)) {
+ report(0, "Enable failed. pmcw: %x", pmcw->flags);
+ return;
+ }
+ report(1, "Tested");
+}
+
static struct {
const char *name;
void (*func)(void);
} tests[] = {
{ "enumerate (stsch)", test_enumerate },
+ { "enable (msch)", test_enable },
{ NULL, NULL }
};

--
2.25.1