[Qemu-devel] [PATCH 5/9] s390x: refactor error handling for XSCH handler

[Halil Pasic <pasic@linux.vnet.ibm.com>]

Simplify the error handling of the XSCH handler avoiding arbitrary and
cryptic error codes being mapped to what a subchannel is supposed to do.
Let the code detecting the condition tell how it's to be handled in a
less ambiguous way.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Pierre Morel<pmorel@linux.vnet.ibm.com>
---
 hw/s390x/css.c         | 19 +++++++------------
 include/hw/s390x/css.h |  2 +-
 target/s390x/ioinst.c  | 27 +++++++++------------------
 3 files changed, 17 insertions(+), 31 deletions(-)

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 1102642c10..7880c2c025 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1237,15 +1237,14 @@ out:
     return ret;
 }
 
-int css_do_xsch(SubchDev *sch)
+void css_do_xsch(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;
+        sch->iret.cc = 3;
+        return;
     }
 
     if (!(s->ctrl & SCSW_CTRL_MASK_FCTL) ||
@@ -1253,13 +1252,13 @@ int css_do_xsch(SubchDev *sch)
         (!(s->ctrl &
            (SCSW_ACTL_RESUME_PEND | SCSW_ACTL_START_PEND | SCSW_ACTL_SUSP))) ||
         (s->ctrl & SCSW_ACTL_SUBCH_ACTIVE)) {
-        ret = -EBUSY;
-        goto out;
+        sch->iret.cc = 2;
+        return;
     }
 
     if (s->ctrl & SCSW_CTRL_MASK_STCTL) {
-        ret = -EINPROGRESS;
-        goto out;
+        sch->iret.cc = 1;
+        return;
     }
 
     /* Cancel the current operation. */
@@ -1271,10 +1270,6 @@ int css_do_xsch(SubchDev *sch)
     sch->last_cmd_valid = false;
     s->dstat = 0;
     s->cstat = 0;
-    ret = 0;
-
-out:
-    return ret;
 }
 
 int css_do_csch(SubchDev *sch)
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index d093181a9e..d78ee5714b 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -204,7 +204,7 @@ void css_conditional_io_interrupt(SubchDev *sch);
 int css_do_stsch(SubchDev *sch, SCHIB *schib);
 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
 int css_do_msch(SubchDev *sch, const SCHIB *schib);
-int css_do_xsch(SubchDev *sch);
+void css_do_xsch(SubchDev *sch);
 int css_do_csch(SubchDev *sch);
 int css_do_hsch(SubchDev *sch);
 void css_do_ssch(SubchDev *sch, ORB *orb);
diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index e8044068c2..f8e038fac7 100644
--- a/target/s390x/ioinst.c
+++ b/target/s390x/ioinst.c
@@ -41,8 +41,6 @@ void ioinst_handle_xsch(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);
@@ -50,24 +48,17 @@ void ioinst_handle_xsch(S390CPU *cpu, uint64_t reg1)
     }
     trace_ioinst_sch_id("xsch", cssid, ssid, schid);
     sch = css_find_subch(m, cssid, ssid, schid);
-    if (sch && css_subch_visible(sch)) {
-        ret = css_do_xsch(sch);
+    if (!sch || !css_subch_visible(sch)) {
+        setcc(cpu, 3);
+        return;
     }
-    switch (ret) {
-    case -ENODEV:
-        cc = 3;
-        break;
-    case -EBUSY:
-        cc = 2;
-        break;
-    case 0:
-        cc = 0;
-        break;
-    default:
-        cc = 1;
-        break;
+    css_subch_clear_iret(sch);
+    css_do_xsch(sch);
+    if (sch->iret.pgm_chk) {
+        program_interrupt(&cpu->env, sch->iret.irq_code, 4);
+        return;
     }
-    setcc(cpu, cc);
+    setcc(cpu, sch->iret.cc);
 }
 
 void ioinst_handle_csch(S390CPU *cpu, uint64_t reg1)
-- 
2.13.5