[Qemu-devel] [PATCH 1/2] s390: Fix error handling and condition code of service call

[Alexander Graf <agraf@suse.de>]

From: Christian Borntraeger <borntraeger@de.ibm.com>

Invalid sccb addresses will cause specification or addressing exception.
Lets add those checks. Furthermore, the good case (cc=0) was incorrect
for KVM, we did not set the CC at all. We now use return codes < 0
as program checks and return codes > 0 as condition code values.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 target-s390x/kvm.c       |    5 +++--
 target-s390x/op_helper.c |   27 ++++++++++++++++++---------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 47008c2..07edf93 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -273,9 +273,10 @@ static int kvm_sclp_service_call(CPUS390XState *env, struct kvm_run *run,
     code = env->regs[(ipbh0 & 0xf0) >> 4];
 
     r = sclp_service_call(env, sccb, code);
-    if (r) {
-        setcc(env, 3);
+    if (r < 0) {
+        enter_pgmcheck(env, -r);
     }
+    setcc(env, r);
 
     return 0;
 }
diff --git a/target-s390x/op_helper.c b/target-s390x/op_helper.c
index 7b72473..91dd8dc 100644
--- a/target-s390x/op_helper.c
+++ b/target-s390x/op_helper.c
@@ -19,6 +19,8 @@
  */
 
 #include "cpu.h"
+#include "memory.h"
+#include "cputlb.h"
 #include "dyngen-exec.h"
 #include "host-utils.h"
 #include "helper.h"
@@ -2366,6 +2368,9 @@ static void ext_interrupt(CPUS390XState *env, int type, uint32_t param,
     cpu_inject_ext(env, type, param, param64);
 }
 
+/*
+ * ret < 0 indicates program check, ret = 0,1,2,3 -> cc
+ */
 int sclp_service_call(CPUS390XState *env, uint32_t sccb, uint64_t code)
 {
     int r = 0;
@@ -2375,10 +2380,12 @@ int sclp_service_call(CPUS390XState *env, uint32_t sccb, uint64_t code)
     printf("sclp(0x%x, 0x%" PRIx64 ")\n", sccb, code);
 #endif
 
+    /* basic checks */
+    if (!memory_region_is_ram(phys_page_find(sccb >> TARGET_PAGE_BITS)->mr)) {
+        return -PGM_ADDRESSING;
+    }
     if (sccb & ~0x7ffffff8ul) {
-        fprintf(stderr, "KVM: invalid sccb address 0x%x\n", sccb);
-        r = -1;
-        goto out;
+        return -PGM_SPECIFICATION;
     }
 
     switch(code) {
@@ -2405,22 +2412,24 @@ int sclp_service_call(CPUS390XState *env, uint32_t sccb, uint64_t code)
 #ifdef DEBUG_HELPER
             printf("KVM: invalid sclp call 0x%x / 0x%" PRIx64 "x\n", sccb, code);
 #endif
-            r = -1;
+            r = 3;
             break;
     }
 
-out:
     return r;
 }
 
 /* SCLP service call */
 uint32_t HELPER(servc)(uint32_t r1, uint64_t r2)
 {
-    if (sclp_service_call(env, r1, r2)) {
-        return 3;
-    }
+    int r;
 
-    return 0;
+    r = sclp_service_call(env, r1, r2);
+    if (r < 0) {
+        program_interrupt(env, -r, 4);
+        return 0;
+    }
+    return r;
 }
 
 /* DIAG */
-- 
1.6.0.2