[Qemu-devel] Re: [PATCH 1/3]: vmware backdoor interface fix

[Anthony Liguori]

Gleb Natapov wrote:
> On Mon, Jul 28, 2008 at 01:58:16PM -0500, Anthony Liguori wrote:
>   
> > Chris Lalancette wrote:
> >     
> > > VMWare backdoor interface should work with IN/OUT port ops, but
> > > currently only IN is supported. BOCHS bios uses OUT to query UUID.
> > > The patch adds OUT support.
> > >
> > > Signed-off-by: Chris Lalancette <address@hidden>
> > > Cc: Gleb Natapov <address@hidden>
> > > Cc: Anthony Liguori <address@hidden>
> > >   
> > >       
> > Applied.  Thanks.
> >
> > I'm going to hold off on the rest of the series until we work out a  
> > better way to support -uuid.  This is a pretty obvious fix though.
> >
> >     
> I don't get this logic. Either delete backdoor interface entirely, or
> use is for something it was intended to be used for (uuid interface is
> documented and proposed implementation is compatible with VMWare).

The issue with supporting the uuid interface is not implementing that 
portion of the backdoor interface.  I'm actually quite okay with that.

But if we're going to support a -uuid option, then I don't want it to 
only work with the backdoor interface.  It should be plumbed through to 
the SMBIOS tables because this is what users are going to expect.

However, we should not be using the backdoor interface as a 
communications mechanism between QEMU and the Bochs BIOS.

We support the backdoor interface because we could use it to implement 
vmmouse.  We are not going to implement the full backdoor interface 
because it requires that you break the x86 ISA by allowing the backdoor 
port to be used when IOPL < CPL.

Regards,

Anthony Liguori

>  Why
> fix something you are not going to use?
>
> --
>                         Gleb.
>