[kvm-unit-tests PATCH v6 10/10] s390x: css: ping pong

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

To test a write command with the SSCH instruction we need a QEMU device,
with control unit type 0xC0CA. The PONG device is such a device.

This type of device responds to PONG_WRITE requests by incrementing an
integer, stored as a string at offset 0 of the CCW data.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
s390x/css.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)

diff --git a/s390x/css.c b/s390x/css.c
index b9dbf01..7cd8731 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -23,6 +23,12 @@
#define PSW_PRG_MASK (PSW_MASK_EA | PSW_MASK_BA)

#define PONG_CU_TYPE 0xc0ca
+/* Channel Commands for PONG device */
+#define PONG_WRITE 0x21 /* Write */
+#define PONG_READ 0x22 /* Read buffer */
+
+#define BUFSZ 9
+static char buffer[BUFSZ];

struct lowcore *lowcore = (void *)0x0;

@@ -262,6 +268,53 @@ unreg_cb:
unregister_io_int_func(irq_io);
}

+static void test_ping(void)
+{
+ int success, result;
+ int cnt = 0, max = 4;
+
+ if (senseid.cu_type != PONG_CU) {
+ report_skip("No PONG, no ping-pong");
+ return;
+ }
+
+ result = register_io_int_func(irq_io);
+ if (result) {
+ report(0, "Could not register IRQ handler");
+ return;
+ }
+
+ while (cnt++ < max) {
+ snprintf(buffer, BUFSZ, "%08x\n", cnt);
+ success = start_subchannel(PONG_WRITE, buffer, BUFSZ);
+ if (!success) {
+ report(0, "start_subchannel failed");
+ goto unreg_cb;
+ }
+
+ wfi(PSW_MASK_IO);
+
+ success = start_subchannel(PONG_READ, buffer, BUFSZ);
+ if (!success) {
+ report(0, "start_subchannel failed");
+ goto unreg_cb;
+ }
+
+ wfi(PSW_MASK_IO);
+
+ result = atol(buffer);
+ if (result != (cnt + 1)) {
+ report(0, "Bad answer from pong: %08x - %08x",
+ cnt, result);
+ goto unreg_cb;
+ }
+ }
+ report(1, "ping-pong count 0x%08x", cnt);
+
+unreg_cb:
+ unregister_io_int_func(irq_io);
+}
+
static struct {
const char *name;
void (*func)(void);
@@ -269,6 +322,7 @@ static struct {
{ "enumerate (stsch)", test_enumerate },
{ "enable (msch)", test_enable },
{ "sense (ssch/tsch)", test_sense },
+ { "ping-pong (ssch/tsch)", test_ping },
{ NULL, NULL }
};

--
2.25.1