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author | Pasi Kärkkäinen <pasik@iki.fi> | 2012-09-10 11:13:54 +0100 |
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committer | Pasi Kärkkäinen <pasik@iki.fi> | 2012-09-10 11:13:54 +0100 |
commit | bee26d2e15090425f70fa7b5769ea9bd1cdd9100 (patch) | |
tree | af216c2ec321338b12b6ebd9e805c7b8719f20a8 /docs | |
parent | 4760e67ccd29aba4406230d411ec2635dfb8f7a7 (diff) | |
download | xen-bee26d2e15090425f70fa7b5769ea9bd1cdd9100.tar.gz xen-bee26d2e15090425f70fa7b5769ea9bd1cdd9100.tar.bz2 xen-bee26d2e15090425f70fa7b5769ea9bd1cdd9100.zip |
xl.cfg: gfx_passthru 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-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
Diffstat (limited to 'docs')
-rw-r--r-- | docs/man/xl.cfg.pod.5 | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5 index 8a0069ac82..a8b635b539 100644 --- a/docs/man/xl.cfg.pod.5 +++ b/docs/man/xl.cfg.pod.5 @@ -992,7 +992,44 @@ certainly belong in a more appropriate section. =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> |