On Tue, Sep 29, 2015 at 08:00:13PM +0100, Dr. David Alan Gilbert wrote:
> * Haozhong Zhang (haozhong.zhang@xxxxxxxxx) wrote:
> > The newly added subsection 'vmstate_tsc_khz' in this patch results in
> > vcpu's TSC rate being saved on the source machine and loaded on the
> > target machine during the migration.
> >
> > Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
>
> Hi,
> I'd appreciate it if you could tie this to only do it on newer
> machine types; that way it won't break back migration.
>
Does "back migration" mean migrating from QEMU w/ vmstate_tsc_khz
subsection to QEMU w/o that subsection?
- Haozhong
> Dave
>
> > ---
> > target-i386/machine.c | 20 ++++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/target-i386/machine.c b/target-i386/machine.c
> > index 9fa0563..80108a3 100644
> > --- a/target-i386/machine.c
> > +++ b/target-i386/machine.c
> > @@ -752,6 +752,25 @@ static const VMStateDescription vmstate_xss = {
> > }
> > };
> >
> > +static bool tsc_khz_needed(void *opaque)
> > +{
> > + X86CPU *cpu = opaque;
> > + CPUX86State *env = &cpu->env;
> > +
> > + return env->tsc_khz != 0;
> > +}
> > +
> > +static const VMStateDescription vmstate_tsc_khz = {
> > + .name = "cpu/tsc_khz",
> > + .version_id = 1,
> > + .minimum_version_id = 1,
> > + .needed = tsc_khz_needed,
> > + .fields = (VMStateField[]) {
> > + VMSTATE_INT64(env.tsc_khz, X86CPU),
> > + VMSTATE_END_OF_LIST()
> > + }
> > +};
> > +
> > VMStateDescription vmstate_x86_cpu = {
> > .name = "cpu",
> > .version_id = 12,
> > @@ -871,6 +890,7 @@ VMStateDescription vmstate_x86_cpu = {
> > &vmstate_msr_hyperv_crash,
> > &vmstate_avx512,
> > &vmstate_xss,
> > + &vmstate_tsc_khz,
> > NULL
> > }
> > };
> > --
> > 2.4.8
> >
> >
> --
> Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
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