Re: [Qemu-devel] [PATCH v1 08/11] s390x: allow only 1 CPU with TCG

[David Hildenbrand]

On 31.08.2017 16:41, Cornelia Huck wrote:
> On Wed, 30 Aug 2017 19:05:58 +0200
> David Hildenbrand <address@hidden> wrote:
> 
>> 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 <address@hidden>
>> ---
>>  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);
> 
> Make this a #define, so we can just flip the switch when smp support is
> ready?

As an alternative: yield a warning?

> 
>> +        exit(1);
>> +    }
>>  
>>      ms->cpus = g_new0(S390CPU *, max_cpus);
>>  
> 


-- 

Thanks,

David