Re: [Qemu-ppc] [Qemu-devel] [PATCH v3 1/3] target-i386: add a subsection for migrating vcpu's TSC rate

[Haozhong Zhang]

On 11/11/15 22:27, Haozhong Zhang wrote:
> On 11/11/15 12:16, Eduardo Habkost wrote:
[...]
> > > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> > > index 2f8f396..858ed69 100644
> > > --- a/hw/i386/pc_q35.c
> > > +++ b/hw/i386/pc_q35.c
> > > @@ -385,6 +385,7 @@ static void pc_q35_2_4_machine_options(MachineClass 
> > > *m)
> > >      pc_q35_2_5_machine_options(m);
> > >      m->alias = NULL;
> > >      pcmc->broken_reserved_end = true;
> > > +    pcmc->save_tsc_khz = false;
> > 
> > I had suggested the PCMachineClass field, but now I've been thinking:
> > all other fields related to tsc_khz are in X86CPU, so I believe this
> > belongs to X86CPU too. It could be a simple X86CPU property set by
> > PC_COMPAT_2_4.
> >
> 
> Reasonable, will update in the next version.

Or maybe no ...

I think there is still a problem to set a X86CPU property in
PC_COMPAT_2_4:

if I create a property for save_tsc_khz by adding
  DEFINE_PROP_BOOL("save-tsc-freq", X86CPU, save_tsc_khz, true)
in x86_cpu_properties and add
  {
      .driver   = TYPE_X86_CPU,
      .property = "save-tsc-freq",
      .value    = "off",
  }
in PC_COMPAT_2_4, then "save-tsc-freq" will also become a
user-visible cpu option. But we agreed on keeping it as an
internal flag in the previous discussion.

Any other ways to set a property in PC_COMPAT_* while keeping that
property internal?

Haozhong