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

[Igor Mammedov]

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<address@hidden>
>
> 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