[Qemu-devel] [PATCH 18/25] s390x/ioinst: Rework memory access in STSCH instruction

[Jens Freimann <jfrei@linux.vnet.ibm.com>]

From: Thomas Huth <thuth@linux.vnet.ibm.com>

Change the handler for STSCH to use the new logical memory
access functions.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 target-s390x/ioinst.c | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/target-s390x/ioinst.c b/target-s390x/ioinst.c
index 0ef7a93..23c2faf 100644
--- a/target-s390x/ioinst.c
+++ b/target-s390x/ioinst.c
@@ -284,8 +284,7 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
     SubchDev *sch;
     uint64_t addr;
     int cc;
-    SCHIB *schib;
-    hwaddr len = sizeof(*schib);
+    SCHIB schib;
     CPUS390XState *env = &cpu->env;
 
     addr = decode_basedisp_s(env, ipb);
@@ -293,21 +292,23 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
         program_interrupt(env, PGM_SPECIFICATION, 2);
         return;
     }
-    schib = s390_cpu_physical_memory_map(env, addr, &len, 1);
-    if (!schib || len != sizeof(*schib)) {
-        program_interrupt(env, PGM_ADDRESSING, 2);
-        goto out;
-    }
 
     if (ioinst_disassemble_sch_ident(reg1, &m, &cssid, &ssid, &schid)) {
-        program_interrupt(env, PGM_OPERAND, 2);
-        goto out;
+        /*
+         * As operand exceptions have a lower priority than access exceptions,
+         * we check whether the memory area is writeable (injecting the
+         * access execption if it is not) first.
+         */
+        if (!s390_cpu_virt_mem_check_write(cpu, addr, sizeof(schib))) {
+            program_interrupt(env, PGM_OPERAND, 2);
+        }
+        return;
     }
     trace_ioinst_sch_id("stsch", cssid, ssid, schid);
     sch = css_find_subch(m, cssid, ssid, schid);
     if (sch) {
         if (css_subch_visible(sch)) {
-            css_do_stsch(sch, schib);
+            css_do_stsch(sch, &schib);
             cc = 0;
         } else {
             /* Indicate no more subchannels in this css/ss */
@@ -318,14 +319,21 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
             cc = 3; /* No more subchannels in this css/ss */
         } else {
             /* Store an empty schib. */
-            memset(schib, 0, sizeof(*schib));
+            memset(&schib, 0, sizeof(schib));
             cc = 0;
         }
     }
+    if (cc != 3) {
+        if (s390_cpu_virt_mem_write(cpu, addr, &schib, sizeof(schib)) != 0) {
+            return;
+        }
+    } else {
+        /* Access exceptions have a higher priority than cc3 */
+        if (s390_cpu_virt_mem_check_write(cpu, addr, sizeof(schib)) != 0) {
+            return;
+        }
+    }
     setcc(cpu, cc);
-
-out:
-    s390_cpu_physical_memory_unmap(env, schib, len, 1);
 }
 
 int ioinst_handle_tsch(CPUS390XState *env, uint64_t reg1, uint32_t ipb)
-- 
2.1.4