s390x/tcg: simplify machine check handling

We currently only support CRW machine checks. This is a preparation for
real floating interrupt support.

Get rid of the queue and handle it via the bit INTERRUPT_MCHK. We don't
rename it for now, as it will be soon gone (when moving crw machine checks
into the flic).

Please note that this is the same way also KVM handles it: only one
instance of a machine check can be pending at a time. So no need for a
queue.

While at it, make sure we try to deliver only if env->cregs[14]
actually indicates that CRWs are accepted.

Drop two unused defines on the way (we already have PSW_MASK_...).

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20180129125623.21729-5-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

1 files changed, 5 insertions, 24 deletions

diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
index 97caa7f418..0cbc4051d1 100644
--- a/target/s390x/excp_helper.c
+++ b/target/s390x/excp_helper.c
@@ -368,30 +368,16 @@ static void do_io_interrupt(CPUS390XState *env)
 
 static void do_mchk_interrupt(CPUS390XState *env)
 {
-    S390CPU *cpu = s390_env_get_cpu(env);
     uint64_t mask, addr;
     LowCore *lowcore;
-    MchkQueue *q;
     int i;
 
-    if (!(env->psw.mask & PSW_MASK_MCHECK)) {
-        cpu_abort(CPU(cpu), "Machine check w/o mchk mask\n");
-    }
+    /* for now we only support channel report machine checks (floating) */
+    g_assert(env->psw.mask & PSW_MASK_MCHECK);
+    g_assert(env->cregs[14] & CR14_CHANNEL_REPORT_SC);
 
-    if (env->mchk_index < 0 || env->mchk_index >= MAX_MCHK_QUEUE) {
-        cpu_abort(CPU(cpu), "Mchk queue overrun: %d\n", env->mchk_index);
-    }
-
-    q = &env->mchk_queue[env->mchk_index];
-
-    if (q->type != 1) {
-        /* Don't know how to handle this... */
-        cpu_abort(CPU(cpu), "Unknown machine check type %d\n", q->type);
-    }
-    if (!(env->cregs[14] & (1 << 28))) {
-        /* CRW machine checks disabled */
-        return;
-    }
+    g_assert(env->pending_int & INTERRUPT_MCHK);
+    env->pending_int &= ~INTERRUPT_MCHK;
 
     lowcore = cpu_map_lowcore(env);
 
@@ -418,11 +404,6 @@ static void do_mchk_interrupt(CPUS390XState *env)
 
     cpu_unmap_lowcore(lowcore);
 
-    env->mchk_index--;
-    if (env->mchk_index == -1) {
-        env->pending_int &= ~INTERRUPT_MCHK;
-    }
-
     DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
             env->psw.mask, env->psw.addr);