Re: [Xen-devel] [PATCH v2] xl.cfg: gfx_passthru documentation improvements

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2012-09-05 at 21:08 +0100, Pasi KÃrkkÃinen wrote:
> Hello,
> 
> v2: address review comments.
> 
> xl.cfg.pod.5 documentation improvements:
> 
> - gfx_passthru: Document gfx_passthru makes the GPU become primary in the 
> guest
>   and other generic info about gfx_passthru.
> 
> Signed-off-by: Pasi KÃrkkÃinen <pasik@xxxxxx>

Acked + applied, thanks.

Jan, I think this docs only change can be a candidate for 4.2.0, but if
not then 4.2.1 would be good. 

Ian.

> 
> 
> --- xen-unstable.hg/docs/man/xl.cfg.pod.5.orig  2012-09-05 22:51:39.745137076 
> +0300
> +++ xen-unstable.hg/docs/man/xl.cfg.pod.5       2012-09-05 23:02:29.746203364 
> +0300
> @@ -992,7 +992,44 @@
> 
>  =item B<gfx_passthru=BOOLEAN>
> 
> -Enable graphics device PCI passthrough. XXX which device is passed through ?
> +Enable graphics device PCI passthrough. This option makes the passthru
> +graphics card become primary graphics card in the VM, so the Qemu emulated
> +graphics adapter is disabled, and the VNC console for the VM won't have
> +any graphics output. All graphics output, including boot time Qemu BIOS
> +messages from the VM, will go to the physical outputs of the passed thru
> +physical graphics card.
> +
> +Graphics card PCI device to passthru is chosen with B<pci> option,
> +exactly in the same way as normal Xen PCI device passthru/assignment is done.
> +Note that gfx_passthru doesn't do any kind of sharing
> +of the GPU, so you can only assign the GPU to one single VM at a time.
> +
> +gfx_passthru also enables various legacy VGA memory ranges, BARs, MMIOs,
> +and ioports to be passed thru to the VM, since those are required
> +for correct operation of things like VGA BIOS, text mode, VBE, etc.
> +
> +Enabling gfx_passthru option also copies the physical graphics card
> +video BIOS to the guest memory, and executes the VBIOS in the guest
> +to get the graphics card initialized.
> +
> +Most graphics adapters require vendor specific tweaks for properly
> +working graphics passthru. See the XenVGAPassthroughTestedAdapters
> +L<http://wiki.xen.org/wiki/XenVGAPassthroughTestedAdapters>
> +wiki page for currently supported graphics cards for gfx_passthru.
> +
> +gfx_passthru is currently only supported with the qemu-xen-traditional
> +device-model. Upstream qemu-xen device-model currently doesn't have
> +support for gfx_passthru.
> +
> +Note that some graphics adapters (AMD/ATI cards, for example) don't
> +necessarily require gfx_passthru option, so you can use the normal
> +Xen PCI passthru to assign the graphics card as a secondary graphics card
> +to the VM. Qemu emulated graphics card stays as the primary graphics card,
> +and you get VNC output from the Qemu-emulated primary adapter.
> +
> +More information about Xen gfx_passthru feature is available
> +on the XenVGAPassthrough L<http://wiki.xen.org/wiki/XenVGAPassthrough>
> +wiki page.
> 
>  =item B<nomigrate=BOOLEAN>
> 



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