[PATCH] xl.cfg: gfx_passthru documentation improvements

[PATCH] xl.cfg: gfx_passthru documentation improvements

[Pasi Kärkkäinen]

[-- Attachment #1: Type: text/plain, Size: 2419 bytes --]

Hello,

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 Kärkkäinen <pasik@iki.fi>

--- docs/man/xl.cfg.pod.5.orig1 2012-09-02 07:16:39.316782158 +0300
+++ docs/man/xl.cfg.pod.5       2012-09-02 08:26:40.081639087 +0300
@@ -968,7 +968,43 @@
 
 =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. Xen currently includes necessary tweaks
+for Intel IGD (Integrated Graphics Device) GPUs.  
+
+Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
+but there are out-of-tree patches available.
+
+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.
+
 
 =item B<nomigrate=BOOLEAN>


[-- Attachment #2: xl.cfg.pod.5-gfx_passthru.patch --]
[-- Type: text/x-diff, Size: 2190 bytes --]

--- docs/man/xl.cfg.pod.5.orig1	2012-09-02 07:16:39.316782158 +0300
+++ docs/man/xl.cfg.pod.5	2012-09-02 08:26:40.081639087 +0300
@@ -968,7 +968,43 @@
 
 =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. Xen currently includes necessary tweaks
+for Intel IGD (Integrated Graphics Device) GPUs.  
+
+Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
+but there are out-of-tree patches available.
+
+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.
+
 
 =item B<nomigrate=BOOLEAN>
 

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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Re: [PATCH] xl.cfg: gfx_passthru documentation improvements

[Ian Campbell]

On Sun, 2012-09-02 at 06:35 +0100, Pasi Kärkkäinen wrote:
> Hello,
> 
> 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 Kärkkäinen <pasik@iki.fi>
> --- docs/man/xl.cfg.pod.5.orig1 2012-09-02 07:16:39.316782158 +0300
> +++ docs/man/xl.cfg.pod.5       2012-09-02 08:26:40.081639087 +0300
> @@ -968,7 +968,43 @@
>  
>  =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,

The option is slightly misnamed then I guess, a better name would have
been gfx_passthru_primary? oh well, we are stuck with it now.

(Am I alone in thinking that "thru" is a horrible alternative to
through?)

>  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 

"BIOS" and (I expect) "VBIOS"?

> +to get the graphics card initialized.
> +
> +Most graphics adapters require vendor specific tweaks for properly
> +working graphics passthru. Xen currently includes necessary tweaks
> +for Intel IGD (Integrated Graphics Device) GPUs.  
> +
> +Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
> +but there are out-of-tree patches available.

If there is a comprehensive list of supported/not-supported devices on
the wiki then I think a reference here would be more useful than these
two brief paragraphs.

In particular the second isn't very useful without links and those tend
to become out of date in docs IME, I would tend to omit this from here
and instead include them in the wiki where they can be kept up to date
(or better yet somebody could finally submit the patches for inclusion).

> +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.
> +
>  
>  =item B<nomigrate=BOOLEAN>
> 



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Re: [PATCH] xl.cfg: gfx_passthru documentation improvements

[Pasi Kärkkäinen]

On Mon, Sep 03, 2012 at 11:10:53AM +0100, Ian Campbell wrote:
> On Sun, 2012-09-02 at 06:35 +0100, Pasi Kärkkäinen wrote:
> > Hello,
> > 
> > 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 Kärkkäinen <pasik@iki.fi>
> > --- docs/man/xl.cfg.pod.5.orig1 2012-09-02 07:16:39.316782158 +0300
> > +++ docs/man/xl.cfg.pod.5       2012-09-02 08:26:40.081639087 +0300
> > @@ -968,7 +968,43 @@
> >  
> >  =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,
> 
> The option is slightly misnamed then I guess, a better name would have
> been gfx_passthru_primary? oh well, we are stuck with it now.
> 

Yeah.. I think earlier gfx_passthru wasn't a boolean, but an integer, to choose the mode.

> (Am I alone in thinking that "thru" is a horrible alternative to
> through?)
> 

:) 

> >  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 
> 
> "BIOS" and (I expect) "VBIOS"?
> 

video bios == vbios, or did you ask something else? 


> > +to get the graphics card initialized.
> > +
> > +Most graphics adapters require vendor specific tweaks for properly
> > +working graphics passthru. Xen currently includes necessary tweaks
> > +for Intel IGD (Integrated Graphics Device) GPUs.  
> > +
> > +Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
> > +but there are out-of-tree patches available.
> 
> If there is a comprehensive list of supported/not-supported devices on
> the wiki then I think a reference here would be more useful than these
> two brief paragraphs.
> 

We have a list, but it's not up-to-date unfortunately:
http://wiki.xen.org/wiki/XenVGAPassthroughTestedAdapters


> In particular the second isn't very useful without links and those tend
> to become out of date in docs IME, I would tend to omit this from here
> and instead include them in the wiki where they can be kept up to date
>

Ok. I'll fix that, and add a link to:
http://wiki.xen.org/wiki/XenVGAPassthrough


> (or better yet somebody could finally submit the patches for inclusion).
> 

Indeed. I was talking to both AMD and Nvidia engineers at XenSummit NA 2012,
and there's some hope for them to do some work on this stuff :) 

And I volunteered earlier for this aswell, but so far I've been way too busy with other things :(


> > +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.
> > +
> >  
> >  =item B<nomigrate=BOOLEAN>
> > 
> 


-- Pasi

Re: [PATCH] xl.cfg: gfx_passthru documentation improvements

[Ian Campbell]

On Tue, 2012-09-04 at 20:12 +0100, Pasi Kärkkäinen wrote:
> On Mon, Sep 03, 2012 at 11:10:53AM +0100, Ian Campbell wrote:
> > On Sun, 2012-09-02 at 06:35 +0100, Pasi Kärkkäinen wrote:
> > > Hello,
> > > 
> > > 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 Kärkkäinen <pasik@iki.fi>
> > > --- docs/man/xl.cfg.pod.5.orig1 2012-09-02 07:16:39.316782158 +0300
> > > +++ docs/man/xl.cfg.pod.5       2012-09-02 08:26:40.081639087 +0300
> > > @@ -968,7 +968,43 @@
> > >  
> > >  =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,
> > 
> > The option is slightly misnamed then I guess, a better name would have
> > been gfx_passthru_primary? oh well, we are stuck with it now.
> > 
> 
> Yeah.. I think earlier gfx_passthru wasn't a boolean, but an integer, to choose the mode.

Oh, do you happen to know what the meanings were?

> > >  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 
> > 
> > "BIOS" and (I expect) "VBIOS"?
> > 
> 
> video bios == vbios, or did you ask something else? 

I was just commenting on the capitalisation differing from other
mentions of the BIOS.

> > > +to get the graphics card initialized.
> > > +
> > > +Most graphics adapters require vendor specific tweaks for properly
> > > +working graphics passthru. Xen currently includes necessary tweaks
> > > +for Intel IGD (Integrated Graphics Device) GPUs.  
> > > +
> > > +Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
> > > +but there are out-of-tree patches available.
> > 
> > If there is a comprehensive list of supported/not-supported devices on
> > the wiki then I think a reference here would be more useful than these
> > two brief paragraphs.
> > 
> 
> We have a list, but it's not up-to-date unfortunately:
> http://wiki.xen.org/wiki/XenVGAPassthroughTestedAdapters

I think it is worth referencing it, and perhaps adding a note to the
page itself regarding its freshness (and then working to improve it, of
course ;-))

> > In particular the second isn't very useful without links and those tend
> > to become out of date in docs IME, I would tend to omit this from here
> > and instead include them in the wiki where they can be kept up to date
> >
> 
> Ok. I'll fix that, and add a link to:
> http://wiki.xen.org/wiki/XenVGAPassthrough

Thanks.

Ian.


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Re: [PATCH] xl.cfg: gfx_passthru documentation improvements

[Pasi Kärkkäinen]

On Wed, Sep 05, 2012 at 09:33:20AM +0100, Ian Campbell wrote:
> On Tue, 2012-09-04 at 20:12 +0100, Pasi Kärkkäinen wrote:
> > On Mon, Sep 03, 2012 at 11:10:53AM +0100, Ian Campbell wrote:
> > > On Sun, 2012-09-02 at 06:35 +0100, Pasi Kärkkäinen wrote:
> > > > Hello,
> > > > 
> > > > 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 Kärkkäinen <pasik@iki.fi>
> > > > --- docs/man/xl.cfg.pod.5.orig1 2012-09-02 07:16:39.316782158 +0300
> > > > +++ docs/man/xl.cfg.pod.5       2012-09-02 08:26:40.081639087 +0300
> > > > @@ -968,7 +968,43 @@
> > > >  
> > > >  =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,
> > > 
> > > The option is slightly misnamed then I guess, a better name would have
> > > been gfx_passthru_primary? oh well, we are stuck with it now.
> > > 
> > 
> > Yeah.. I think earlier gfx_passthru wasn't a boolean, but an integer, to choose the mode.
> 
> Oh, do you happen to know what the meanings were?
> 

iirc off/primary/secondary.. 


> > > >  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 
> > > 
> > > "BIOS" and (I expect) "VBIOS"?
> > > 
> > 
> > video bios == vbios, or did you ask something else? 
> 
> I was just commenting on the capitalisation differing from other
> mentions of the BIOS.
> 

Ok.

> > > > +to get the graphics card initialized.
> > > > +
> > > > +Most graphics adapters require vendor specific tweaks for properly
> > > > +working graphics passthru. Xen currently includes necessary tweaks
> > > > +for Intel IGD (Integrated Graphics Device) GPUs.  
> > > > +
> > > > +Support for AMD/Nvidia gfx_passthru is not yet merged to Xen,
> > > > +but there are out-of-tree patches available.
> > > 
> > > If there is a comprehensive list of supported/not-supported devices on
> > > the wiki then I think a reference here would be more useful than these
> > > two brief paragraphs.
> > > 
> > 
> > We have a list, but it's not up-to-date unfortunately:
> > http://wiki.xen.org/wiki/XenVGAPassthroughTestedAdapters
> 
> I think it is worth referencing it, and perhaps adding a note to the
> page itself regarding its freshness (and then working to improve it, of
> course ;-))
> 

Yep.

> > > In particular the second isn't very useful without links and those tend
> > > to become out of date in docs IME, I would tend to omit this from here
> > > and instead include them in the wiki where they can be kept up to date
> > >
> > 
> > Ok. I'll fix that, and add a link to:
> > http://wiki.xen.org/wiki/XenVGAPassthrough
> 
> Thanks.
> 

I'll send a new patch soon.

-- Pasi

[PATCH v2] xl.cfg: gfx_passthru documentation improvements

[Pasi Kärkkäinen]

[-- Attachment #1: Type: text/plain, Size: 2583 bytes --]

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 Kärkkäinen <pasik@iki.fi>


--- 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>


[-- Attachment #2: xl.cfg.pod.5-gfx_passthru-2.patch --]
[-- Type: text/x-diff, Size: 2336 bytes --]

--- 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>
 

[-- Attachment #3: Type: text/plain, Size: 126 bytes --]

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

[Ian Campbell]

On Wed, 2012-09-05 at 21:08 +0100, Pasi Kärkkäinen 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 Kärkkäinen <pasik@iki.fi>

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

[Pasi Kärkkäinen]

On Mon, Sep 10, 2012 at 11:15:11AM +0100, Ian Campbell wrote:
> On Wed, 2012-09-05 at 21:08 +0100, Pasi Kärkkäinen 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 Kärkkäinen <pasik@iki.fi>
> 
> Acked + applied, thanks.
> 

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. 
> 

Yes please, it would be nice to get this into 4.2.0 if possible.. it's a docs only patch.

-- Pasi

> 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>
> > 
> 
>