Re: [PATCH] KVM: add support for AMD nested live migration

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> Il mer 1 lug 2020, 18:28 Dr. David Alan Gilbert <dgilbert@redhat.com> ha
> scritto:
> 
> >
> > > +    return (nested_state->format == KVM_STATE_NESTED_FORMAT_SVM &&
> > > +            nested_state->size > offsetof(struct kvm_nested_state,
> > data));
> >
> > How does this nested_state->size work? It looks like even if it's 1 byte
> > into 'data' we transmit a whole KVM_STATE_NESTED_SVM_VMCB_SIZE.
> >
> 
> The format is documented as having either 0 or KVM_STATE_NESTED_SVM_VMCB_SIZE
> bytes (for vmx instead it can be 0, 4K or 8K).

OK.

Dave

> Paolo
> 
> 
> > Dave
> >
> > > +}
> > > +
> > > +static const VMStateDescription vmstate_svm_nested_state = {
> > > +    .name = "cpu/kvm_nested_state/svm",
> > > +    .version_id = 1,
> > > +    .minimum_version_id = 1,
> > > +    .needed = svm_nested_state_needed,
> > > +    .fields = (VMStateField[]) {
> > > +        VMSTATE_U64(hdr.svm.vmcb_pa, struct kvm_nested_state),
> > > +        VMSTATE_UINT8_ARRAY(data.svm[0].vmcb12,
> > > +                            struct kvm_nested_state,
> > > +                            KVM_STATE_NESTED_SVM_VMCB_SIZE),
> > > +        VMSTATE_END_OF_LIST()
> > > +    }
> > > +};
> > > +
> > >  static bool nested_state_needed(void *opaque)
> > >  {
> > >      X86CPU *cpu = opaque;
> > >      CPUX86State *env = &cpu->env;
> > >
> > >      return (env->nested_state &&
> > > -            vmx_nested_state_needed(env->nested_state));
> > > +            (vmx_nested_state_needed(env->nested_state) ||
> > > +             svm_nested_state_needed(env->nested_state)));
> > >  }
> > >
> > >  static int nested_state_post_load(void *opaque, int version_id)
> > > @@ -1139,6 +1166,7 @@ static const VMStateDescription
> > vmstate_kvm_nested_state = {
> > >      },
> > >      .subsections = (const VMStateDescription*[]) {
> > >          &vmstate_vmx_nested_state,
> > > +        &vmstate_svm_nested_state,
> > >          NULL
> > >      }
> > >  };
> > > --
> > > 2.26.2
> > >
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >
> >
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK