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[v3,11/21] s390x: allow only 1 CPU with TCG

Message ID 20170907201335.13956-12-david@redhat.com
State New
Headers show
Series s390x cleanups and CPU hotplug via device_add | expand

Commit Message

David Hildenbrand Sept. 7, 2017, 8:13 p.m. UTC 
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 is specified, so we don't raise people's
hope. Make it a define, so we can easily bump it up later.

Tested-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/s390x/s390-virtio-ccw.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
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Patch

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index f67b4b5d58..f1198b2745 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"
@@ -47,6 +48,8 @@  S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
     return cpu_states[cpu_addr];
 }
 
+/* #define S390_TCG_SMP_SUPPORT */
+
 static void s390_init_cpus(MachineState *machine)
 {
     int i;
@@ -55,6 +58,13 @@  static void s390_init_cpus(MachineState *machine)
     if (machine->cpu_model == NULL) {
         machine->cpu_model = s390_default_cpu_model_name();
     }
+#ifndef S390_TCG_SMP_SUPPORT
+    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);
+    }
+#endif
 
     cpu_states = g_new0(S390CPU *, max_cpus);