From bee26d2e15090425f70fa7b5769ea9bd1cdd9100 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pasi=20K=C3=A4rkk=C3=A4inen?= Date: Mon, 10 Sep 2012 11:13:54 +0100 Subject: xl.cfg: gfx_passthru documentation improvements MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Ian Campbell Committed-by: Ian Campbell --- docs/man/xl.cfg.pod.5 | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) (limited to 'docs/man') 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 -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 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 +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 +wiki page. =item B -- cgit v1.2.3