[kvm-unit-tests PATCH v5 09/10] s390x: css: ssch/tsch with sense and interrupt

Pierre Morel
2020-02-20T12:00:54Z

We add a new css_lib file to contain the I/O function we may
share with different tests.
First function is the subchannel_enable() function.

When a channel is enabled we can start a SENSE ID command using
the SSCH instruction to recognize the control unit and device.

This tests the success of SSCH, the I/O interruption and the TSCH
instructions.

The test expects a device with a control unit type of 0xC0CA as the
first subchannel of the CSS.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
lib/s390x/asm/arch_def.h | 1 +
lib/s390x/asm/time.h | 10 +++
lib/s390x/css.h | 20 ++++++
lib/s390x/css_lib.c | 55 ++++++++++++++
s390x/Makefile | 1 +
s390x/css.c | 152 +++++++++++++++++++++++++++++++++++++++
6 files changed, 239 insertions(+)
create mode 100644 lib/s390x/css_lib.c

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 863c2bf..ab3fc9d 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -10,6 +10,7 @@
#ifndef _ASM_S390X_ARCH_DEF_H_
#define _ASM_S390X_ARCH_DEF_H_

+#define PSW_MASK_IO 0x0200000000000000UL
#define PSW_MASK_EXT 0x0100000000000000UL
#define PSW_MASK_DAT 0x0400000000000000UL
#define PSW_MASK_PSTATE 0x0001000000000000UL
diff --git a/lib/s390x/asm/time.h b/lib/s390x/asm/time.h
index 25c7a3c..d3e4eab 100644
--- a/lib/s390x/asm/time.h
+++ b/lib/s390x/asm/time.h
@@ -23,4 +23,14 @@ static inline uint64_t get_clock_ms(void)
return (clk >> (63 - 51)) / 1000;
}

+static inline void delay(unsigned long ms)
+{
+ unsigned long startclk;
+
+ startclk = get_clock_ms();
+ for (;;)
+ if (get_clock_ms() - startclk > ms)
+ break;
+}
+
#endif
diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index 448e597..b6ab0ba 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -97,6 +97,19 @@ struct irb {
uint32_t emw[8];
} __attribute__ ((aligned(4)));

+#define CCW_CMD_SENSE_ID 0xe4
+#define PONG_CU 0xc0ca
+struct senseid {
+ /* common part */
+ uint8_t reserved; /* always 0x'FF' */
+ uint16_t cu_type; /* control unit type */
+ uint8_t cu_model; /* control unit model */
+ uint16_t dev_type; /* device type */
+ uint8_t dev_model; /* device model */
+ uint8_t unused; /* padding byte */
+ uint8_t padding[256 - 10]; /* Extra padding for CCW */
+} __attribute__ ((aligned(4))) __attribute__ ((packed));
+
/* CSS low level access functions */

static inline int ssch(unsigned long schid, struct orb *addr)
@@ -254,4 +267,11 @@ static inline struct ccw *dump_ccw(struct ccw *cp)
return NULL;
}
#endif /* DEBUG_CSS */
+
+#define SID_ONE 0x00010000
+
+/* Library functions */
+int enable_subchannel(unsigned int sid);
+int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw);
+
#endif
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
new file mode 100644
index 0000000..15d767a
--- /dev/null
+++ b/lib/s390x/css_lib.c
@@ -0,0 +1,55 @@
+/*
+ * Channel subsystem library functions
+ *
+ * Copyright (c) 2019 IBM Corp.
+ *
+ * Authors:
+ * Pierre Morel <pmorel@linux.ibm.com>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License version 2.
+ */
+#include <stdint.h>
+#include <stddef.h>
+#include <css.h>
+
+int enable_subchannel(unsigned int sid)
+{
+ struct schib schib;
+ struct pmcw *pmcw = &schib.pmcw;
+ int try_count = 5;
+ int cc;
+
+ if (!(sid & SID_ONE))
+ return -1;
+
+ cc = stsch(sid, &schib);
+ if (cc)
+ return -cc;
+
+ do {
+ pmcw->flags |= PMCW_ENABLE;
+
+ cc = msch(sid, &schib);
+ if (cc)
+ return -cc;
+
+ cc = stsch(sid, &schib);
+ if (cc)
+ return -cc;
+
+ } while (!(pmcw->flags & PMCW_ENABLE) && --try_count);
+
+ return try_count;
+}
+
+int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw)
+{
+ struct orb orb;
+
+ orb.intparm = sid;
+ orb.ctrl = ORB_F_INIT_IRQ|ORB_F_FORMAT|ORB_F_LPM_DFLT;
+ orb.cpa = (unsigned int) (unsigned long)ccw;
+
+ return ssch(sid, &orb);
+}
diff --git a/s390x/Makefile b/s390x/Makefile
index baebf18..166cb5c 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -53,6 +53,7 @@ cflatobjs += lib/s390x/interrupt.o
cflatobjs += lib/s390x/mmu.o
cflatobjs += lib/s390x/smp.o
cflatobjs += lib/s390x/css_dump.o
+cflatobjs += lib/s390x/css_lib.o

OBJDIRS += lib/s390x

diff --git a/s390x/css.c b/s390x/css.c
index aeee951..b9805a9 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -22,9 +22,34 @@
#include <asm/time.h>

#define SID_ONE 0x00010000
+#define PSW_PRG_MASK (PSW_MASK_IO | PSW_MASK_EA | PSW_MASK_BA)
+
+#define PONG_CU_TYPE 0xc0ca
+
+struct lowcore *lowcore = (void *)0x0;

static struct schib schib;
static int test_device_sid;
+#define NUM_CCW 100
+static struct ccw1 ccw[NUM_CCW];
+static struct irb irb;
+static struct senseid senseid;
+
+static void set_io_irq_subclass_mask(uint64_t const new_mask)
+{
+ asm volatile (
+ "lctlg %%c6, %%c6, %[source]\n"
+ : /* No outputs */
+ : [source] "R" (new_mask));
+}
+
+static void set_system_mask(uint8_t new_mask)
+{
+ asm volatile (
+ "ssm %[source]\n"
+ : /* No outputs */
+ : [source] "R" (new_mask));
+}

static void test_enumerate(void)
{
@@ -115,12 +140,139 @@ static void test_enable(void)
report(1, "Tested");
}

+static void enable_io_irq(void)
+{
+ /* Let's enable all ISCs for I/O interrupt */
+ set_io_irq_subclass_mask(0x00000000ff000000);
+ set_system_mask(PSW_PRG_MASK >> 56);
+}
+
+static void irq_io(void)
+{
+ int ret = 0;
+ char *flags;
+ int sid;
+
+ report_prefix_push("Interrupt");
+ /* Lowlevel set the SID as interrupt parameter. */
+ if (lowcore->io_int_param != test_device_sid) {
+ report(0, "Bad io_int_param: %x expected %x", lowcore->io_int_param, test_device_sid);
+ report_prefix_pop();
+ return;
+ }
+ report_prefix_pop();
+
+ report_prefix_push("tsch");
+ sid = lowcore->subsys_id_word;
+ ret = tsch(sid, &irb);
+ switch (ret) {
+ case 1:
+ dump_irb(&irb);
+ flags = dump_scsw_flags(irb.scsw.ctrl);
+ report(0, "I/O interrupt, but sch not status pending: %s", flags);
+ goto pop;
+ case 2:
+ report(0, "TSCH returns unexpected CC 2");
+ goto pop;
+ case 3:
+ report(0, "Subchannel %08x not operational", sid);
+ goto pop;
+ case 0:
+ /* Stay humble on success */
+ break;
+ }
+pop:
+ report_prefix_pop();
+}
+
+static int start_subchannel(int code, void *data, int count)
+{
+ int ret;
+
+ report_prefix_push("start_senseid");
+ /* Build the CCW chain with a single CCW */
+ ccw[0].code = code;
+ ccw[0].flags = 0; /* No flags need to be set */
+ ccw[0].count = count;
+ ccw[0].data_address = (int)(unsigned long)data;
+
+ ret = start_ccw1_chain(test_device_sid, ccw);
+ if (ret) {
+ report(0, "start_ccw_chain failed ret=%d", ret);
+ report_prefix_pop();
+ return 0;
+ }
+ report_prefix_pop();
+ return 1;
+}
+
+/*
+ * test_sense
+ * Pre-requisits:
+ * - We need the QEMU PONG device as the first recognized
+ * device by the enumeration.
+ * - ./s390x-run s390x/css.elf -device ccw-pong,cu_type=0xc0ca
+ */
+static void test_sense(void)
+{
+ int ret;
+
+ if (!test_device_sid) {
+ report_skip("No device");
+ return;
+ }
+
+ ret = enable_subchannel(test_device_sid);
+ if (ret < 0) {
+ report(0, "Could not enable the subchannel: %08x", test_device_sid);
+ return;
+ }
+
+ ret = register_io_int_func(irq_io);
+ if (ret) {
+ report(0, "Could not register IRQ handler");
+ goto unreg_cb;
+ }
+
+ enable_io_irq();
+ lowcore->io_int_param = 0;
+
+ ret = start_subchannel(CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
+ if (!ret) {
+ report(0, "start_senseid failed");
+ goto unreg_cb;
+ }
+
+ /* 100ms should be enough for the interruption to fire */
+ delay(100);
+ if (lowcore->io_int_param != test_device_sid) {
+ report(0, "No interrupts. io_int_param: expect 0x%08x, got 0x%08x",
+ test_device_sid, lowcore->io_int_param);
+ goto unreg_cb;
+ }
+
+ report_info("reserved %02x cu_type %04x cu_model %02x dev_type %04x dev_model %02x\n",
+ senseid.reserved, senseid.cu_type, senseid.cu_model,
+ senseid.dev_type, senseid.dev_model);
+
+ if (senseid.cu_type == PONG_CU)
+ report(1, "cu_type: expect 0x%04x got 0x%04x",
+ PONG_CU_TYPE, senseid.cu_type);
+ else
+ report(0, "cu_type: expect 0x%04x got 0x%04x",
+ PONG_CU_TYPE, senseid.cu_type);
+
+unreg_cb:
+ unregister_io_int_func(irq_io);
+}
+
static struct {
const char *name;
void (*func)(void);
} tests[] = {
{ "enumerate (stsch)", test_enumerate },
{ "enable (msch)", test_enable },
+ { "sense (ssch/tsch)", test_sense },
{ NULL, NULL }
};

--
2.17.0