Re: [Qemu-devel] [PATCH 3/3] S390: Enable -cpu help and QMP query-cpu-definitions

["Andreas Färber" <afaerber@suse.de>]

Am 17.12.2012 15:47, schrieb Alexander Graf:
> 
> On 14.12.2012, at 17:46, Jens Freimann wrote:
> 
>> From: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
>>
>> This enables qemu -cpu help to return a list of supported CPU models
>> on s390 and also to query for cpu definitions in the monitor.
>> Initially only cpu model = host is returned. This needs to be reworked
>> into a full-fledged CPU model handling later on.
>> This change is needed to allow libvirt exploiters (like OpenStack)
>> to specify a CPU model.
>>
>> Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
>> Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
>> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>> v1 -> v2:
>> * only print output with CONFIG_KVM
>>
>> ---
>> hw/s390-virtio.c   |  6 +++++-
>> target-s390x/cpu.c | 23 +++++++++++++++++++++++
>> target-s390x/cpu.h |  3 +++
>> 3 files changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
>> index a350430..60fde26 100644
>> --- a/hw/s390-virtio.c
>> +++ b/hw/s390-virtio.c
>> @@ -2,6 +2,7 @@
>>  * QEMU S390 virtio target
>>  *
>>  * Copyright (c) 2009 Alexander Graf <agraf@suse.de>
>> + * Copyright IBM Corp 2012
>>  *
>>  * This library is free software; you can redistribute it and/or
>>  * modify it under the terms of the GNU Lesser General Public
>> @@ -13,7 +14,10 @@
>>  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>>  * Lesser General Public License for more details.
>>  *
>> - * You should have received a copy of the GNU Lesser General Public
>> + * Contributions after 2012-10-29 are licensed under the terms of the
>> + * GNU GPL, version 2 or (at your option) any later version.
>> + *
>> + * You should have received a copy of the GNU (Lesser) General Public
>>  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
>>  */
>>
>> diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
>> index 75d4036..adca789 100644
>> --- a/target-s390x/cpu.c
>> +++ b/target-s390x/cpu.c
>> @@ -28,8 +28,31 @@
>> #include "hw/hw.h"
>> #include "qemu-common.h"
>> #include "qemu-timer.h"
>> +#include "arch_init.h"
>>
>>
>> +/* generate CPU information for cpu -? */
>> +void s390_cpu_list(FILE *f, fprintf_function cpu_fprintf)
>> +{
>> +#ifdef CONFIG_KVM
>> +    (*cpu_fprintf)(f, "s390 %16s\n", "host");
>> +#endif
>> +}
>> +
> 
> static const struct CpuDefinitionInfo cpu_info[] = {
> #ifdef CONFIG_KVM
>     {
>         .name = "host",
>     },
> #endif
> };
> 
> static const struct CPUDefinitionInfoList cpu_entry = {
>     value = cpu_info,
> };
> 
>> +CpuDefinitionInfoList *arch_query_cpu_definitions(Error **errp)
>> +{
>> +    CpuDefinitionInfoList *entry;
>> +    CpuDefinitionInfo *info;
>> +
>> +    info = g_malloc0(sizeof(*info));
>> +    info->name = g_strdup("host");
>> +
>> +    entry = g_malloc0(sizeof(*entry));
>> +    entry->value = info;
> 
> return &entry;
> 
> (completely untested, don't you think the above would work? The code as is looks quite leaky.)

target-i386 does it the same way (well, not hardcoding "host"
obviously), so if there's leaks they need to be solved in generic code.

Mid-term we want to generate this list on the fly from CPU subclasses,
so I don't see the utility of starting a static model list for QMP only.
Given that subclasses are really easy to introduce, we might as well do
that. We could leave s390-cpu non-abstract as fallback for the non-host
cpu_models plus one host-s390-cpu for -cpu host; only thing to keep in
mind then is that the base class is not automatically filtered out, as
relied on for other targets.

Andreas

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