Re: [Qemu-devel] i386: EFER vs 32-bit CPU

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

* Pavel Dovgalyuk (dovgaluk@ispras.ru) wrote:
> > From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> > On 29/05/19 13:30, Dr. David Alan Gilbert wrote:
> > >> Should we add a section for i386, which duplicates efer, or just version_id of the main
> > VMSD should
> > >> be updated?
> > >
> > > You could do:
> > >
> > > #ifdef TARGET_X86_64
> > >         VMSTATE_UINT64(env.efer, X86CPU),
> > >         VMSTATE_UINT64(env.star, X86CPU),
> > > ...
> > >
> > > to become:
> > >
> > >         VMSTATE_UINT64_TEST(env.efer, X86CPU, efer_needed)
> > > #ifdef TARGET_X86_64
> > >         VMSTATE_UINT64(env.star, X86CPU),
> > >
> > >
> > > and then make efer_needed a function that returns true if
> > > TARGET_X86_64 or it's a new machine type that knows about whatever
> > > you're going to do with it.
> > 
> > I prefer adding a subsection for 32-bit, so that EFER is saved/restored
> > if nonzero.
> 
> The question is: should we remove EFER from the original VMSD?

No, because that would break 64bit compat.

Dave

> Pavel Dovgalyuk
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK