[kvm-unit-tests PATCH v4 7/9] s390x: css: msch, enable test

Pierre Morel
2019-12-11T15:46:24Z

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 success of the MSCH instruction by enabling a channel.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
s390x/css.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/s390x/css.c b/s390x/css.c
index dfab35f..b8824ad 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -19,12 +19,24 @@
#include <asm/time.h>

#include <css.h>
+#include <asm/time.h>

#define SID_ONE 0x00010000

static struct schib schib;
static int test_device_sid;

+static inline void delay(unsigned long ms)
+{
+ unsigned long startclk;
+
+ startclk = get_clock_ms();
+ for (;;) {
+ if (get_clock_ms() - startclk > ms)
+ break;
+ }
+}
+
static void test_enumerate(void)
{
struct pmcw *pmcw = &schib.pmcw;
@@ -64,11 +76,64 @@ out:
report(1, "Devices, tested: %d, I/O type: %d", scn, scn_found);
}

+static void test_enable(void)
+{
+ struct pmcw *pmcw = &schib.pmcw;
+ int count = 0;
+ 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
+ * insert a little delay and try 5 times.
+ */
+ do {
+ cc = stsch(test_device_sid, &schib);
+ if (cc) {
+ report(0, "stsch cc=%d", cc);
+ return;
+ }
+ delay(10);
+ } while (!(pmcw->flags & PMCW_ENABLE) && count++ < 5);
+
+ 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 }
};

--
2.17.0