Re: [Xen-devel][PATCH 1/3] VT-d: support Intel IGD passthrough

[Weidong Han <weidong.han@xxxxxxxxx>]

Isaku Yamahata wrote:
> On Fri, Feb 05, 2010 at 09:52:47AM +0800, Weidong Han wrote:
>   
> > Ian Jackson wrote:
> >     
> > > Han, Weidong writes ("[Xen-devel][PATCH 1/3] VT-d: support Intel IGD passthrough 
> > > "):
> > >   
> > >       
> > > > Some registers of Intel IGD are mapped in host bridge, so it needs
> > > > to passthrough these registers of physical host bridge to guest
> > > > because emulated host bridge in guest doesn't have these mappings.
> > > >
> > > > Some VBIOSs and drivers ssume the IGD BDF (bus:device:function) is
> > > > always 00:02.0, so this patch reserves 00:02.0 for assigned IGD in
> > > > guest.
> > > >     
> > > >         
> > > Thanks for the contribution, which I have applied with a very small
> > > change to avoid having an open else at #endif.
> > >
> > > However the part in pci.c is really very ugly indeed.  If we ever get
> > > around to rebasing to recent upstream qemu and trying to upstream our
> > > patches, this is sure to be dropped.  So you might profitably spend
> > > some time thinking how to make it less ugly.
> > >
> > > Thanks,
> > > Ian.
> > >   
> > >       
> > Thanks for check-in.  I agree the hacking in pci.c is not elegant. We  
> > will think how to make it cleaner.
> >     
> This can be moved out as read_config callback.
> See 400fx_init() calling pci_register_device() in pciix_pci.c
> and some wrapper of pt_cpi_read_config().
>
> thanks,
>
>   
Sound reasonable.

Regards,
Weidong
> > Regards,
> > Weidong
> >
> >
> >     
> > >   
> > >       
> > > > +#ifdef CONFIG_PASSTHROUGH
> > > > +    /* host bridge reads for IGD passthrough */
> > > > +    if ( igd_passthru && pci_dev->devfn == 0x00 )
> > > > +    {
> > > > +        val = pci_dev->config_read(pci_dev, config_addr, len);
> > > > +
> > > > +        if ( config_addr == 0x00 && len == 4 )
> > > > +            val = pt_pci_host_read_long(0, 0, 0, 0x00);
> > > > +        else if ( config_addr == 0x02 ) // Device ID
> > > > +            val = pt_pci_host_read_word(0, 0, 0, 0x02);
> > > > +        else if ( config_addr == 0x52 ) // GMCH Graphics Control Register
> > > > +            val = pt_pci_host_read_word(0, 0, 0, 0x52);
> > > > +        else if ( config_addr == 0xa0 ) // GMCH Top of Memory Register
> > > > +            val = pt_pci_host_read_word(0, 0, 0, 0xa0);
> > > > +    }
> > > > +    else if ( igd_passthru && pci_dev->devfn == 0x10 &&
> > > > +              config_addr == 0xfc ) // read on IGD device
> > > > +        val = 0;  // use SMI to communicate with the system BIOS
> > > > +    else
> > > > +#endif
> > > > +        val = pci_dev->config_read(pci_dev, config_addr, len);
> > > > +
> > > >     
> > > >         
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> >
> >     
>   
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