setup_vga_pt seems can not correctly use vgabios.

setup_vga_pt seems can not correctly use vgabios.

[成会明]

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hi, 

In xen-4.3.0/tools/qemu-xen-traditional/hw/pt-graphics.c,  setup_vga_pt calls get_vgabios to get vgabios of passed-through VGA adapter, but get_vgabios only read bios from /dev/mem,  /dev/mem is domain 0’s memory device. /dev/mem should only contain the vgabios of primary VGA adapter of domain 0.

So if I want to pass through secondary adapter of domain 0 to domain U. setup_vga_pt cannot correctly setup VGABIOS for domain U. Is this correct? Any comments are appreciated.

thanks
huiming


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Re: setup_vga_pt seems can not correctly use vgabios.

[Zytaruk, Kelly]

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On Monday, October 28, 2013 3:24 PM Huiming wrote;
>hi,
>
>In xen-4.3.0/tools/qemu-xen-traditional/hw/pt-graphics.c,  setup_vga_pt calls get_vgabios
>to get vgabios of passed->through VGA adapter, but get_vgabios only read bios from /dev/mem,
>/dev/mem is domain 0’s memory device. /dev/mem >should only contain the vgabios of primary
>VGA adapter of domain 0.
>
>So if I want to pass through secondary adapter of domain 0 to domain U. setup_vga_pt cannot
>correctly setup VGABIOS for >domain U. Is this correct? Any comments are appreciated.
>
>thanks
>huiming

This is only a problem if you are trying to pass the Dom0 secondary adapter through as a
primary adapter to the DomU.  In this case the DomU will have the wrong VBios.

There is no problem if you are passing the Dom0 secondary adapter through as a secondary
adapter to DomU.  In this case the emulated (Cirrus) VBios will be properly copied to 0xc0000.

Thanks,
Kelly

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Re: setup_vga_pt seems can not correctly use vgabios.

[Youenn Gestin]

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Hello,

I'm not a dev, but shouldn't it be possible to use one of the method
described here for that (for nvidia and perhaps other brand )? :

http://nouveau.freedesktop.org/wiki/DumpingVideoBios/

I used the "using /sys" method to dump mine with sysrescue cd and under
my dom0, the md5sum is the same, and it was recognised by a nvidia's
bios editor

Regards.

Le 28/10/2013 20:45, Zytaruk, Kelly a écrit :
>
> On Monday, October 28, 2013 3:24 PM Huiming wrote;
>
> >hi,
>
> > 
>
> >In xen-4.3.0/tools/qemu-xen-traditional/hw/pt-graphics.c, 
> setup_vga_pt calls get_vgabios
>
> >to get vgabios of passed->through VGA adapter, but get_vgabios only
> read bios from /dev/mem,
>
> >/dev/mem is domain 0's memory device. /dev/mem >should only contain
> the vgabios of primary
>
> >VGA adapter of domain 0.
>
> > 
>
> >So if I want to pass through secondary adapter of domain 0 to domain
> U. setup_vga_pt cannot
>
> >correctly setup VGABIOS for >domain U. Is this correct? Any comments
> are appreciated.
>
> > 
>
> >thanks
>
> >huiming
>
>  
>
> This is only a problem if you are trying to pass the Dom0 secondary
> adapter through as a
>
> primary adapter to the DomU.  In this case the DomU will have the
> wrong VBios.
>
>  
>
> There is no problem if you are passing the Dom0 secondary adapter
> through as a secondary
>
> adapter to DomU.  In this case the emulated (Cirrus) VBios will be
> properly copied to 0xc0000.
>
>  
>
> Thanks,
>
> Kelly
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


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