target-s390x: basic PER event handling

This patch add basic support to generate PER exceptions. It adds two
fields to the cpu structure to record for the PER address and PER
code & ATMID values. When an exception is triggered and a PER event is
pending, the two PER values are copied to the lowcore area.

At the end of an instruction, an helper is checking for a possible
pending PER event and triggers an exception in that case. For that to
work with branches, we need to disable TB chaining when PER is
activated. Fortunately it's already in the TB flags.

Finally in case of a SERVICE CALL exception, we need to trigger the PER
exception immediately after.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 35 insertions, 19 deletions

diff --git a/target-s390x/helper.c b/target-s390x/helper.c
index 90d273c098..ec847a2645 100644
--- a/target-s390x/helper.c
+++ b/target-s390x/helper.c
@@ -250,25 +250,6 @@ void do_restart_interrupt(CPUS390XState *env)
     load_psw(env, mask, addr);
 }
 
-static void do_svc_interrupt(CPUS390XState *env)
-{
-    uint64_t mask, addr;
-    LowCore *lowcore;
-
-    lowcore = cpu_map_lowcore(env);
-
-    lowcore->svc_code = cpu_to_be16(env->int_svc_code);
-    lowcore->svc_ilen = cpu_to_be16(env->int_svc_ilen);
-    lowcore->svc_old_psw.mask = cpu_to_be64(get_psw_mask(env));
-    lowcore->svc_old_psw.addr = cpu_to_be64(env->psw.addr + env->int_svc_ilen);
-    mask = be64_to_cpu(lowcore->svc_new_psw.mask);
-    addr = be64_to_cpu(lowcore->svc_new_psw.addr);
-
-    cpu_unmap_lowcore(lowcore);
-
-    load_psw(env, mask, addr);
-}
-
 static void do_program_interrupt(CPUS390XState *env)
 {
     uint64_t mask, addr;
@@ -292,6 +273,14 @@ static void do_program_interrupt(CPUS390XState *env)
 
     lowcore = cpu_map_lowcore(env);
 
+    /* Signal PER events with the exception.  */
+    if (env->per_perc_atmid) {
+        env->int_pgm_code |= PGM_PER;
+        lowcore->per_address = cpu_to_be64(env->per_address);
+        lowcore->per_perc_atmid = cpu_to_be16(env->per_perc_atmid);
+        env->per_perc_atmid = 0;
+    }
+
     lowcore->pgm_ilen = cpu_to_be16(ilen);
     lowcore->pgm_code = cpu_to_be16(env->int_pgm_code);
     lowcore->program_old_psw.mask = cpu_to_be64(get_psw_mask(env));
@@ -308,6 +297,33 @@ static void do_program_interrupt(CPUS390XState *env)
     load_psw(env, mask, addr);
 }
 
+static void do_svc_interrupt(CPUS390XState *env)
+{
+    uint64_t mask, addr;
+    LowCore *lowcore;
+
+    lowcore = cpu_map_lowcore(env);
+
+    lowcore->svc_code = cpu_to_be16(env->int_svc_code);
+    lowcore->svc_ilen = cpu_to_be16(env->int_svc_ilen);
+    lowcore->svc_old_psw.mask = cpu_to_be64(get_psw_mask(env));
+    lowcore->svc_old_psw.addr = cpu_to_be64(env->psw.addr + env->int_svc_ilen);
+    mask = be64_to_cpu(lowcore->svc_new_psw.mask);
+    addr = be64_to_cpu(lowcore->svc_new_psw.addr);
+
+    cpu_unmap_lowcore(lowcore);
+
+    load_psw(env, mask, addr);
+
+    /* When a PER event is pending, the PER exception has to happen
+       immediately after the SERVICE CALL one.  */
+    if (env->per_perc_atmid) {
+        env->int_pgm_code = PGM_PER;
+        env->int_pgm_ilen = env->int_svc_ilen;
+        do_program_interrupt(env);
+    }
+}
+
 #define VIRTIO_SUBCODE_64 0x0D00
 
 static void do_ext_interrupt(CPUS390XState *env)