[PATCH 1/2] linux-user/s390x: Fix single-stepping SVC

[Ilya Leoshkevich]

Currently single-stepping SVC executes two instructions. The reason is
that EXCP_DEBUG for the SVC instruction itself is masked by EXCP_SVC.
Fix by re-raising EXCP_DEBUG.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 linux-user/s390x/cpu_loop.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/linux-user/s390x/cpu_loop.c b/linux-user/s390x/cpu_loop.c
index 285bc60071a..8b7ac2879ef 100644
--- a/linux-user/s390x/cpu_loop.c
+++ b/linux-user/s390x/cpu_loop.c
@@ -86,6 +86,15 @@ void cpu_loop(CPUS390XState *env)
             } else if (ret != -QEMU_ESIGRETURN) {
                 env->regs[2] = ret;
             }
+
+            if (unlikely(cs->singlestep_enabled)) {
+                /*
+                 * cpu_tb_exec() did not raise EXCP_DEBUG, because it has seen
+                 * that EXCP_SVC was already pending.
+                 */
+                cs->exception_index = EXCP_DEBUG;
+            }
+
             break;
 
         case EXCP_DEBUG:
-- 
2.40.1