Re: [PATCH v5 4/8] vt82c686: Introduce abstract TYPE_VIA_ISA and base vt82c686b_isa on it

[Dr. David Alan Gilbert]

* David Gibson (david@gibson.dropbear.id.au) wrote:
> On Thu, Mar 04, 2021 at 11:42:10PM +0100, Philippe Mathieu-Daudé wrote:
> > On 3/4/21 9:16 PM, BALATON Zoltan wrote:
> > > On Thu, 4 Mar 2021, Philippe Mathieu-Daudé wrote:
> > >> On 3/2/21 10:11 PM, BALATON Zoltan wrote:
> > >>> To allow reusing ISA bridge emulation for vt8231_isa move the device
> > >>> state of vt82c686b_isa emulation in an abstract via_isa class.
> > >>>
> > >>> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
> > >>> ---
> > >>>  hw/isa/vt82c686.c        | 70 ++++++++++++++++++++++------------------
> > >>>  include/hw/pci/pci_ids.h |  2 +-
> > >>>  2 files changed, 40 insertions(+), 32 deletions(-)
> > >>>
> > >>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
> > >>> index 72234bc4d1..5137f97f37 100644
> > >>> --- a/hw/isa/vt82c686.c
> > >>> +++ b/hw/isa/vt82c686.c
> > >>> @@ -609,24 +609,48 @@ static const TypeInfo vt8231_superio_info = {
> > >>>  };
> > >>>
> > >>>
> > >>> -OBJECT_DECLARE_SIMPLE_TYPE(VT82C686BISAState, VT82C686B_ISA)
> > >>> +#define TYPE_VIA_ISA "via-isa"
> > >>> +OBJECT_DECLARE_SIMPLE_TYPE(ViaISAState, VIA_ISA)
> > >>>
> > >>> -struct VT82C686BISAState {
> > >>> +struct ViaISAState {
> > >>>      PCIDevice dev;
> > >>>      qemu_irq cpu_intr;
> > >>>      ViaSuperIOState *via_sio;
> > >>>  };
> > >>>
> > >>> +static const VMStateDescription vmstate_via = {
> > >>> +    .name = "via-isa",
> > >>
> > >> You changed the migration stream name, so I think we have
> > >> a problem with migration... No clue how to do that properly.
> > > 
> > > I don't think these machines support migration or state description of
> > > vt86c686b was not missing something before these patches that would make
> > > it not work anyway so I did not worry about this too much. I doubt
> > > anybody wants to migrate a fuloong2e machine so this should not be a
> > > problem in practice but maybe you can mention it in the release notes if
> > > you think that would be necessary.
> > 
> > Maybe just add in the description:
> > 
> >  This change breaks migration back compatibility, but
> >  this is not an issue for the Fuloong2E machine.
> 
> Hrm.  If migration was never supported, why is there a vmstate
> description there at all though?
> 
> That said, I don't think breaking compat is a problem: that's only an
> issue where we actually have versioned machine types, which covers
> only pc, pseries, arm virt and a very few others.  I don't think this
> device was used on any of them.

Except 'vt82c686b-usb-uhci' is a generic PCI device that anyone can
instantiate, so it's not actually Fuloong specific.

Dave

> -- 
> David Gibson                  | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au        | minimalist, thank you.  NOT _the_ 
> _other_
>                               | _way_ _around_!
> http://www.ozlabs.org/~dgibson


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