From: David Hildenbrand <david@redhat.com>
Date: Wed, 30 Aug 2017 19:05:58 +0200
Message-Id: <20170830170601.15855-9-david@redhat.com>
In-Reply-To: <20170830170601.15855-1-david@redhat.com>
References: <20170830170601.15855-1-david@redhat.com>
Subject: [Qemu-devel] [PATCH v1 08/11] s390x: allow only 1 CPU with TCG
To: qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>, Aurelien Jarno <aurelien@aurel32.net>, thuth@redhat.com, cohuck@redhat.com, david@redhat.com, borntraeger@de.ibm.com, Alexander Graf <agraf@suse.de>

Specifying more than 1 CPU (e.g. -smp 5) leads to SIGP errors (the
guest tries to bring these CPUs up but fails), because we don't support
multiple CPUs on s390x under TCG.

Let's bail out if more than 1 are specified, so we don't raise people's
hope.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/s390x/s390-virtio-ccw.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 7754e3eaf9..eff96808c4 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -23,6 +23,7 @@
 #include "hw/s390x/css.h"
 #include "virtio-ccw.h"
 #include "qemu/config-file.h"
+#include "qemu/error-report.h"
 #include "s390-pci-bus.h"
 #include "hw/s390x/storage-keys.h"
 #include "hw/s390x/storage-attributes.h"
@@ -56,6 +57,11 @@ static void s390_init_cpus(MachineState *machine)
     if (machine->cpu_model == NULL) {
         machine->cpu_model = s390_default_cpu_model_name();
     }
+    if (tcg_enabled() && max_cpus > 1) {
+        error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
+                     "supported by TCG (1) on s390x", max_cpus);
+        exit(1);
+    }
 
     ms->cpus = g_new0(S390CPU *, max_cpus);
 
-- 
2.13.5