[Qemu-devel] [PULL 20/26] target-s390x: PER instruction-fetch event support

[Alexander Graf <agraf@suse.de>]

From: Aurelien Jarno <aurelien@aurel32.net>

For the PER instruction-fetch, we can't use the QEMU breakpoint
infrastructure as it triggers for a single address and not a full
address range, and as it actually stop before the instruction and
not before.

We therefore call an helper with the just fetched instruction address,
which check if the address is within the PER address range. If it is
the case, an event is recorded and will be signaled through an
exception.

Note that we implement here the PER-3 behaviour, that is an invalid
opcode is not considered as an instruction fetch. Without PER-3 this
behavious is undefined.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 target-s390x/helper.h      | 1 +
 target-s390x/misc_helper.c | 8 ++++++++
 target-s390x/translate.c   | 8 ++++++++
 3 files changed, 17 insertions(+)

diff --git a/target-s390x/helper.h b/target-s390x/helper.h
index 89197cb..7e06119 100644
--- a/target-s390x/helper.h
+++ b/target-s390x/helper.h
@@ -118,6 +118,7 @@ DEF_HELPER_FLAGS_3(stura, TCG_CALL_NO_WG, void, env, i64, i64)
 DEF_HELPER_FLAGS_3(sturg, TCG_CALL_NO_WG, void, env, i64, i64)
 DEF_HELPER_1(per_check_exception, void, env)
 DEF_HELPER_FLAGS_3(per_branch, TCG_CALL_NO_RWG, void, env, i64, i64)
+DEF_HELPER_FLAGS_2(per_ifetch, TCG_CALL_NO_RWG, void, env, i64)
 
 DEF_HELPER_2(xsch, void, env, i64)
 DEF_HELPER_2(csch, void, env, i64)
diff --git a/target-s390x/misc_helper.c b/target-s390x/misc_helper.c
index bc28f9d..73d0193 100644
--- a/target-s390x/misc_helper.c
+++ b/target-s390x/misc_helper.c
@@ -619,4 +619,12 @@ void HELPER(per_branch)(CPUS390XState *env, uint64_t from, uint64_t to)
         }
     }
 }
+
+void HELPER(per_ifetch)(CPUS390XState *env, uint64_t addr)
+{
+    if ((env->cregs[9] & PER_CR9_EVENT_IFETCH) && get_per_in_range(env, addr)) {
+        env->per_address = addr;
+        env->per_perc_atmid = PER_CODE_EVENT_IFETCH | get_per_atmid(env);
+    }
+}
 #endif
diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index 0387806..d69fb5c 100644
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -5187,6 +5187,14 @@ static ExitStatus translate_one(CPUS390XState *env, DisasContext *s)
         return EXIT_NORETURN;
     }
 
+#ifndef CONFIG_USER_ONLY
+    if (s->tb->flags & FLAG_MASK_PER) {
+        TCGv_i64 addr = tcg_const_i64(s->pc);
+        gen_helper_per_ifetch(cpu_env, addr);
+        tcg_temp_free_i64(addr);
+    }
+#endif
+
     /* Check for insn specification exceptions.  */
     if (insn->spec) {
         int spec = insn->spec, excp = 0, r;
-- 
1.7.12.4