Re: [Qemu-devel] [PATCH 1/1] s390-cpu: qom interface for S390 cpu states array

["Jason J. Herne" <jjherne@linux.vnet.ibm.com>]

On 03/07/2014 12:03 PM, Paolo Bonzini wrote:
> Il 07/03/2014 17:29, Jason J. Herne ha scritto:
>> From: "Jason J. Herne" <jjherne@us.ibm.com>
>>
>> Rename the S390 ipi_states array to cpu_states to better reflect its
>> contents.
>>
>> Create machine/cpu[cpu_addr] links within the qom tree when creating a
>> new cpu.
>>
>> Encapsulate the qom tree linking process and the management of the
>> cpu_states
>> array into helper functions.
>>
>> Signed-off-by: Jason J. Herne <jjherne@us.ibm.com>
>> ---
>>  hw/s390x/s390-virtio.c | 30 ++++++++++++++++++++++++------
>>  target-s390x/cpu.h     |  1 +
>>  2 files changed, 25 insertions(+), 6 deletions(-)
>>
>> diff --git a/hw/s390x/s390-virtio.c b/hw/s390x/s390-virtio.c
>> index 9eeda97..82411e7 100644
>> --- a/hw/s390x/s390-virtio.c
>> +++ b/hw/s390x/s390-virtio.c
>> @@ -52,15 +52,33 @@
>>  #define ZIPL_FILENAME                   "s390-zipl.rom"
>>
>>  static VirtIOS390Bus *s390_bus;
>> -static S390CPU **ipi_states;
>> +static S390CPU **cpu_states;
>>
>>  S390CPU *s390_cpu_addr2state(uint16_t cpu_addr)
>>  {
>> +    gchar *name;
>> +    Object *cpu;
>> +
>>      if (cpu_addr >= smp_cpus) {
>>          return NULL;
>>      }
>>
>> -    return ipi_states[cpu_addr];
>> +    name = g_strdup_printf("cpu[%i]", cpu_addr);
>> +    cpu = object_property_get_link(qdev_get_machine(), name, NULL);
>> +
>> +    g_free(name);
>> +    return S390_CPU(cpu);
>> +}
>
> QOM is too slow to be used in the data path.
>
> I don't think you want a malloc + a linear scan of an array in
> css_inject_io_interrupt, so you should keep using cpu_states here.
>

Hi Paolo, I agree. Provided Andreas also agrees I'll include this change 
in my next patch. Thanks.

-- 
-- Jason J. Herne (jjherne@linux.vnet.ibm.com)