s390x: refactor error handling for HSCH handler

Simplify the error handling of the HSCH.  Let the code detecting the
condition tell (in a less ambiguous way) how it's to be handled. No
changes in behavior.
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Message-Id: <20171017140453.51099-7-pasic@linux.vnet.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: NCornelia Huck <cohuck@redhat.com>

hw/s390x/css.c

@@ -1451,28 +1451,24 @@ IOInstEnding css_do_csch(SubchDev *sch)
     return do_subchannel_work(sch);
 }
 
-int css_do_hsch(SubchDev *sch)
+IOInstEnding css_do_hsch(SubchDev *sch)
 {
     SCSW *s = &sch->curr_status.scsw;
     PMCW *p = &sch->curr_status.pmcw;
-    int ret;
 
     if (~(p->flags) & (PMCW_FLAGS_MASK_DNV | PMCW_FLAGS_MASK_ENA)) {
-        ret = -ENODEV;
-        goto out;
+        return IOINST_CC_NOT_OPERATIONAL;
     }
 
     if (((s->ctrl & SCSW_CTRL_MASK_STCTL) == SCSW_STCTL_STATUS_PEND) ||
         (s->ctrl & (SCSW_STCTL_PRIMARY |
                     SCSW_STCTL_SECONDARY |
                     SCSW_STCTL_ALERT))) {
-        ret = -EINPROGRESS;
-        goto out;
+        return IOINST_CC_STATUS_PRESENT;
     }
 
     if (s->ctrl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC)) {
-        ret = -EBUSY;
-        goto out;
+        return IOINST_CC_BUSY;
     }
 
     /* Trigger the halt function. */
@@ -1485,11 +1481,7 @@ int css_do_hsch(SubchDev *sch)
     }
     s->ctrl |= SCSW_ACTL_HALT_PEND;
 
-    do_subchannel_work(sch);
-    ret = 0;
-
-out:
-    return ret;
+    return do_subchannel_work(sch);
 }
 
 static void css_update_chnmon(SubchDev *sch)

include/hw/s390x/css.h

@@ -242,7 +242,7 @@ bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
 int css_do_msch(SubchDev *sch, const SCHIB *schib);
 IOInstEnding css_do_xsch(SubchDev *sch);
 IOInstEnding css_do_csch(SubchDev *sch);
-int css_do_hsch(SubchDev *sch);
+IOInstEnding css_do_hsch(SubchDev *sch);
 IOInstEnding css_do_ssch(SubchDev *sch, ORB *orb);
 int css_do_tsch_get_irb(SubchDev *sch, IRB *irb, int *irb_len);
 void css_do_tsch_update_subch(SubchDev *sch);

target/s390x/ioinst.c

@@ -78,8 +78,6 @@ void ioinst_handle_hsch(S390CPU *cpu, uint64_t reg1)
 {
     int cssid, ssid, schid, m;
     SubchDev *sch;
-    int ret = -ENODEV;
-    int cc;
 
     if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid, &schid)) {
         program_interrupt(&cpu->env, PGM_OPERAND, 4);
@@ -87,24 +85,11 @@ void ioinst_handle_hsch(S390CPU *cpu, uint64_t reg1)
     }
     trace_ioinst_sch_id("hsch", cssid, ssid, schid);
     sch = css_find_subch(m, cssid, ssid, schid);
-    if (sch && css_subch_visible(sch)) {
-        ret = css_do_hsch(sch);
-    }
-    switch (ret) {
-    case -ENODEV:
-        cc = 3;
-        break;
-    case -EBUSY:
-        cc = 2;
-        break;
-    case 0:
-        cc = 0;
-        break;
-    default:
-        cc = 1;
-        break;
+    if (!sch || !css_subch_visible(sch)) {
+        setcc(cpu, 3);
+        return;
     }
-    setcc(cpu, cc);
+    setcc(cpu, css_do_hsch(sch));
 }
 
 static int ioinst_schib_valid(SCHIB *schib)