[kvm-unit-tests PATCH v12 9/9] s390x: css: ssch/tsch with sense and interrupt

Pierre Morel
2020-07-14T11:16:24Z

After a channel is enabled we 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 SENSE_ID command response is tested to report 0xff inside
its reserved field and to report the same control unit type
as the cu_type kernel argument.

Without the cu_type kernel argument, the test expects a device
with a default control unit type of 0x3832, a.k.a virtio-net-ccw.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
lib/s390x/asm/arch_def.h | 1 +
lib/s390x/css.h | 35 ++++++++
lib/s390x/css_lib.c | 180 +++++++++++++++++++++++++++++++++++++++
s390x/css.c | 80 +++++++++++++++++
4 files changed, 296 insertions(+)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 022a564..edc06ef 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -16,6 +16,7 @@ struct psw {
};

#define PSW_MASK_EXT 0x0100000000000000UL
+#define PSW_MASK_IO 0x0200000000000000UL
#define PSW_MASK_DAT 0x0400000000000000UL
#define PSW_MASK_WAIT 0x0002000000000000UL
#define PSW_MASK_PSTATE 0x0001000000000000UL
diff --git a/lib/s390x/css.h b/lib/s390x/css.h
index 63a70f1..e309dac 100644
--- a/lib/s390x/css.h
+++ b/lib/s390x/css.h
@@ -11,6 +11,8 @@
#ifndef CSS_H
#define CSS_H

+#define lowcore_ptr ((struct lowcore *)0x0)
+
/* subchannel ID bit 16 must always be one */
#define SCHID_ONE 0x00010000

@@ -62,9 +64,18 @@ struct orb {
} __attribute__ ((aligned(4)));

struct scsw {
+#define SCSW_SC_PENDING 0x00000001
+#define SCSW_SC_SECONDARY 0x00000002
+#define SCSW_SC_PRIMARY 0x00000004
+#define SCSW_SC_INTERMEDIATE 0x00000008
+#define SCSW_SC_ALERT 0x00000010
uint32_t ctrl;
uint32_t ccw_addr;
+#define SCSW_DEVS_DEV_END 0x04
+#define SCSW_DEVS_SCH_END 0x08
uint8_t dev_stat;
+#define SCSW_SCHS_PCI 0x80
+#define SCSW_SCHS_IL 0x40
uint8_t sch_stat;
uint16_t count;
};
@@ -102,6 +113,19 @@ struct irb {
uint32_t emw[8];
} __attribute__ ((aligned(4)));

+#define CCW_CMD_SENSE_ID 0xe4
+#define CSS_SENSEID_COMMON_LEN 8
+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)
@@ -256,4 +280,15 @@ int css_enumerate(void);

#define IO_SCH_ISC 3
int css_enable(int schid, int isc);
+
+/* Library functions */
+int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw);
+int start_single_ccw(unsigned int sid, int code, void *data, int count,
+ unsigned char flags);
+void css_irq_io(void);
+int css_residual_count(unsigned int schid);
+
+void enable_io_isc(uint8_t isc);
+int wait_and_check_io_completion(int schid);
+
#endif
diff --git a/lib/s390x/css_lib.c b/lib/s390x/css_lib.c
index e47a945..274c293 100644
--- a/lib/s390x/css_lib.c
+++ b/lib/s390x/css_lib.c
@@ -16,6 +16,7 @@
#include <interrupt.h>
#include <asm/arch_def.h>
#include <asm/time.h>
+#include <asm/arch_def.h>

#include <css.h>

@@ -141,3 +142,182 @@ retry:
schid, retry_count, pmcw->flags);
return -1;
}
+
+static struct irb irb;
+
+void css_irq_io(void)
+{
+ int ret = 0;
+ char *flags;
+ int sid;
+
+ report_prefix_push("Interrupt");
+ sid = lowcore_ptr->subsys_id_word;
+ /* Lowlevel set the SID as interrupt parameter. */
+ if (lowcore_ptr->io_int_param != sid) {
+ report(0,
+ "io_int_param: %x differs from subsys_id_word: %x",
+ lowcore_ptr->io_int_param, sid);
+ goto pop;
+ }
+ report_info("subsys_id_word: %08x io_int_param %08x io_int_word %08x",
+ lowcore_ptr->subsys_id_word,
+ lowcore_ptr->io_int_param,
+ lowcore_ptr->io_int_word);
+ report_prefix_pop();
+
+ report_prefix_push("tsch");
+ ret = tsch(sid, &irb);
+ switch (ret) {
+ case 1:
+ dump_irb(&irb);
+ flags = dump_scsw_flags(irb.scsw.ctrl);
+ report(0,
+ "I/O interrupt, but tsch returns CC 1 for subchannel %08x. SCSW flags: %s",
+ sid, flags);
+ break;
+ case 2:
+ report(0, "tsch returns unexpected CC 2");
+ break;
+ case 3:
+ report(0, "tsch reporting sch %08x as not operational", sid);
+ break;
+ case 0:
+ /* Stay humble on success */
+ break;
+ }
+pop:
+ report_prefix_pop();
+ lowcore_ptr->io_old_psw.mask &= ~PSW_MASK_WAIT;
+}
+
+int start_ccw1_chain(unsigned int sid, struct ccw1 *ccw)
+{
+ struct orb orb = {
+ .intparm = sid,
+ .ctrl = ORB_CTRL_ISIC|ORB_CTRL_FMT|ORB_LPM_DFLT,
+ .cpa = (unsigned int) (unsigned long)ccw,
+ };
+
+ return ssch(sid, &orb);
+}
+
+/*
+ * In the future, we want to implement support for CCW chains;
+ * for that, we will need to work with ccw1 pointers.
+ */
+static struct ccw1 unique_ccw;
+
+int start_single_ccw(unsigned int sid, int code, void *data, int count,
+ unsigned char flags)
+{
+ int cc;
+ struct ccw1 *ccw = &unique_ccw;
+
+ report_prefix_push("start_subchannel");
+ /* Build the CCW chain with a single CCW */
+ ccw->code = code;
+ ccw->flags = flags;
+ ccw->count = count;
+ ccw->data_address = (int)(unsigned long)data;
+
+ cc = start_ccw1_chain(sid, ccw);
+ if (cc) {
+ report(0, "cc = %d", cc);
+ report_prefix_pop();
+ return cc;
+ }
+ report_prefix_pop();
+ return 0;
+}
+
+/* wait_and_check_io_completion:
+ * @schid: the subchannel ID
+ *
+ * Makes the most common check to validate a successful I/O
+ * completion.
+ * Only report failures.
+ */
+int wait_and_check_io_completion(int schid)
+{
+ int ret = 0;
+
+ wait_for_interrupt(PSW_MASK_IO);
+
+ report_prefix_push("check I/O completion");
+
+ if (lowcore_ptr->io_int_param != schid) {
+ report(0, "interrupt parameter: expected %08x got %08x",
+ schid, lowcore_ptr->io_int_param);
+ ret = -1;
+ goto end;
+ }
+
+ /* Verify that device status is valid */
+ if (!(irb.scsw.ctrl & SCSW_SC_PENDING)) {
+ report(0, "No status pending after interrupt. Subch Ctrl: %08x",
+ irb.scsw.ctrl);
+ ret = -1;
+ goto end;
+ }
+
+ if (!(irb.scsw.ctrl & (SCSW_SC_SECONDARY | SCSW_SC_PRIMARY))) {
+ report(0, "Primary or secondary status missing. Subch Ctrl: %08x",
+ irb.scsw.ctrl);
+ ret = -1;
+ goto end;
+ }
+
+ if (!(irb.scsw.dev_stat & (SCSW_DEVS_DEV_END | SCSW_DEVS_SCH_END))) {
+ report(0, "No device end or sch end. Dev. status: %02x",
+ irb.scsw.dev_stat);
+ ret = -1;
+ goto end;
+ }
+
+ if (irb.scsw.sch_stat & ~SCSW_SCHS_IL) {
+ report_info("Unexpected Subch. status %02x", irb.scsw.sch_stat);
+ ret = -1;
+ goto end;
+ }
+
+end:
+ report_prefix_pop();
+ return ret;
+}
+
+/*
+ * css_residual_count
+ * Return the residual count, if it is valid.
+ *
+ * Return value:
+ * Success: the residual count
+ * Not meaningful: -1 (-1 can not be a valid count)
+ */
+int css_residual_count(unsigned int schid)
+{
+
+ if (!(irb.scsw.ctrl & (SCSW_SC_PENDING | SCSW_SC_PRIMARY)))
+ goto invalid;
+
+ if (irb.scsw.dev_stat)
+ if (irb.scsw.sch_stat & ~(SCSW_SCHS_PCI | SCSW_SCHS_IL))
+ goto invalid;
+
+ return irb.scsw.count;
+
+invalid:
+ return -1;
+}
+
+/*
+ * enable_io_isc: setup ISC in Control Register 6
+ * @isc: The interruption Sub Class as a bitfield
+ */
+void enable_io_isc(uint8_t isc)
+{
+ uint64_t value;
+
+ value = (uint64_t)isc << 24;
+ lctlg(6, value);
+}
diff --git a/s390x/css.c b/s390x/css.c
index f314a0c..ee3bc83 100644
--- a/s390x/css.c
+++ b/s390x/css.c
@@ -19,7 +19,11 @@

#include <css.h>

+#define DEFAULT_CU_TYPE 0x3832 /* virtio-ccw */
+static unsigned long cu_type = DEFAULT_CU_TYPE;
+
static int test_device_sid;
+static struct senseid senseid;

static void test_enumerate(void)
{
@@ -45,12 +49,87 @@ static void test_enable(void)
report(cc == 0, "Enable subchannel %08x", test_device_sid);
}

+/*
+ * test_sense
+ * Pre-requisites:
+ * - We need the test device as the first recognized
+ * device by the enumeration.
+ */
+static void test_sense(void)
+{
+ int ret;
+ int len;
+
+ if (!test_device_sid) {
+ report_skip("No device");
+ return;
+ }
+
+ ret = css_enable(test_device_sid, IO_SCH_ISC);
+ if (ret) {
+ report(0, "Could not enable the subchannel: %08x",
+ test_device_sid);
+ return;
+ }
+
+ ret = register_io_int_func(css_irq_io);
+ if (ret) {
+ report(0, "Could not register IRQ handler");
+ return;
+ }
+
+ lowcore_ptr->io_int_param = 0;
+
+ memset(&senseid, 0, sizeof(senseid));
+ ret = start_single_ccw(test_device_sid, CCW_CMD_SENSE_ID,
+ &senseid, sizeof(senseid), CCW_F_SLI);
+ if (ret)
+ goto error;
+
+ if (wait_and_check_io_completion(test_device_sid) < 0)
+ goto error;
+
+ /* Test transfer completion */
+ report_prefix_push("ssch transfer completion");
+
+ ret = css_residual_count(test_device_sid);
+
+ if (ret < 0) {
+ report_info("no valid residual count");
+ } else if (ret != 0) {
+ len = sizeof(senseid) - ret;
+ if (ret && len < CSS_SENSEID_COMMON_LEN) {
+ report(0, "transferred a too short length: %d", ret);
+ goto error;
+ } else if (ret && len)
+ report_info("transferred a shorter length: %d", len);
+ }
+
+ if (senseid.reserved != 0xff) {
+ report(0, "transferred garbage: 0x%02x", senseid.reserved);
+ goto error;
+ }
+
+ report_prefix_pop();
+
+ report_info("reserved 0x%02x cu_type 0x%04x cu_model 0x%02x dev_type 0x%04x dev_model 0x%02x",
+ senseid.reserved, senseid.cu_type, senseid.cu_model,
+ senseid.dev_type, senseid.dev_model);
+
+ report(senseid.cu_type == cu_type, "cu_type expected 0x%04x got 0x%04x",
+ (uint16_t) cu_type, senseid.cu_type);
+
+error:
+ unregister_io_int_func(css_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 }
};

@@ -59,6 +138,7 @@ int main(int argc, char *argv[])
int i;

report_prefix_push("Channel Subsystem");
+ enable_io_isc(0x80 >> IO_SCH_ISC);
for (i = 0; tests[i].name; i++) {
report_prefix_push(tests[i].name);
tests[i].func();
--
2.25.1