Re: [Qemu-devel] [PATCH 7/7] Implement cpu hot-add using device_add monitor command

[Igor Mammedov <imammedo@redhat.com>]

On 02/16/2012 12:35 AM, Anthony Liguori wrote:
> On 02/15/2012 05:16 PM, Igor Mammedov wrote:
>> Adds ability to hot-add cpus if guest was started with options
>> -smp X,maxcpus=Y
>> where X< Y.
>> For simplicity sake this implementation doesn't allow to add specific
>> cpu but rather it adds the next not yet plugged cpu.
>>
>> For adding cpu just execute following command in monitor:
>> device_add cpu-pc
>> If guest was started with a specific cpu model, then add option model
>> to cmonitor command. for example:
>> device_add cpu-pc,model="host"
>>
>> Signed-off-by: Igor Mammedov<imammedo@redhat.com>
>
> I don't see how the code matches this description, but unless you've got qdev-ification patches in the earlier ones (haven't made the list yet),
> device_add is not the right place for this.
Indeed, I've attempted qdev-ify cpu first (patch 2/7)

>
> There's no such thing as "cpu-pc" either. You should start with a cpu_add command.
"cpu-pc" is coming from 2/7 where cpu was qdev-ifed and I needed to call it somehow.
Looking at other attempts to qdev-ify cpus i.e. "cpu-ppc", "cpu-mips", I've just
followed trend. Is there any suggestions on how it should be called?

As for cpu_add command, v1 had patch that introduced somewhat similar cpu_set qmp
command. And Jan's opinion on it was that it's not upstream-able, so device_add was
used instead.

>
> Regards,
>
> Anthony Liguori
>
>> ---
>> hw/pc.c | 11 +++++++++++
>> 1 files changed, 11 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/pc.c b/hw/pc.c
>> index ec50f16..5923549 100644
>> --- a/hw/pc.c
>> +++ b/hw/pc.c
>> @@ -44,6 +44,8 @@
>> #include "ui/qemu-spice.h"
>> #include "memory.h"
>> #include "exec-memory.h"
>> +#include "cpus.h"
>> +#include "kvm.h"
>>
>> /* output Bochs bios info messages */
>> //#define DEBUG_BIOS
>> @@ -941,6 +943,10 @@ static int cpu_device_init(ICCBusDevice *dev)
>> #endif
>> }
>>
>> + if (runstate_is_running()) {
>> + pause_all_vcpus();
>> + }
>> +
>> if (cpu_x86_init_inplace(env, cpu->model)< 0) {
>> return -1;
>> }
>> @@ -949,6 +955,11 @@ static int cpu_device_init(ICCBusDevice *dev)
>> env->apic_state = apic_init(env, env->cpuid_apic_id);
>> }
>>
>> + cpu_synchronize_post_init(env);
>> + if (runstate_is_running()) {
>> + resume_all_vcpus();
>> + acpi_cpu_hot_plug(env->cpuid_apic_id, 1);
>> + }
>> return 0;
>> }
>>
>

-- 
Thanks,
  Igor