Re: [Qemu-devel] Re: [PATCH RFC] Mark a device as non-migratable

[Anthony Liguori]

On 06/16/2010 12:05 AM, Cam Macdonell wrote:
> On Tue, Jun 15, 2010 at 4:33 PM, Anthony Liguori<address@hidden>  wrote:
>    
> > On 06/15/2010 05:26 PM, Cam Macdonell wrote:
> >      
> > > On Tue, Jun 15, 2010 at 10:32 AM, Anthony Liguori<address@hidden>
> > >   wrote:
> > >
> > >        
> > > > On 06/15/2010 11:16 AM, Cam Macdonell wrote:
> > > >
> > > >          
> > > > > How does this look for marking the device as non-migratable?  It adds a
> > > > > field
> > > > > 'no_migrate' to the SaveStateEntry and tests for it in vmstate_save.
> > > > >   This
> > > > > would
> > > > > replace anything that touches memory.
> > > > >
> > > > > Cam
> > > > >
> > > > > ---
> > > > >   hw/hw.h  |    1 +
> > > > >   savevm.c |   32 +++++++++++++++++++++++++++++---
> > > > >   2 files changed, 30 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/hw/hw.h b/hw/hw.h
> > > > > index d78d814..7c93f08 100644
> > > > > --- a/hw/hw.h
> > > > > +++ b/hw/hw.h
> > > > > @@ -263,6 +263,7 @@ int register_savevm_live(const char *idstr,
> > > > >                            void *opaque);
> > > > >
> > > > >   void unregister_savevm(const char *idstr, void *opaque);
> > > > > +void mark_no_migrate(const char *idstr, void *opaque);
> > > > >
> > > > >
> > > > >            
> > > > I'm not thrilled with the name but the functionality is spot on.  I lack
> > > > the
> > > > creativity to offer a better name suggestion :-)
> > > >
> > > > Regards,
> > > >
> > > > Anthony Liguori
> > > >
> > > >          
> > > Hmmm, in working on this it seems that the memory (from
> > > qemu_ram_map()) is still attached even when the device is removed
> > > (which causes migration to fail because there is an unexpected
> > > memory).
> > >
> > > Is something like cpu_unregister_physical_memory()/qemu_ram_free() needed?
> > >
> > >        
> > Yes.  You need to unregister any memory that you have registered upon device
> > removal.
> >      
> Is there an established way to achieve this?  I can't seem find
> another device that unregisters memory registered with
> cpu_register_physical_memory().  Is something like
> cpu_unregister_physical_memory() needed?
>    

cpu_register_physical_memory(IO_MEM_UNASSIGNED).

If you look at pci.c, you'll see that it automatically unregisters any 
mapped io regions on remove.

Regards,

Anthony Liguori

> Thanks,
> Cam
>
>    
> > Regards,
> >
> > Anthony Liguori
> >
> >      
> > > Cam
> > >
> > >
> > >        
> >
> >