The VGA passthrough club - did you succeed, and how?

[GizmoChicken]

I never gave XCP a try as I heard that some things are easier to accomplish while others are more difficult. Once I solved the hardware part (graphics card), I felt that Xen is rather straight forward.

Yep, in many ways, vanilla Xen is much more straight forward. And so at this point, I'm mostly just experimenting with XCP. I like the management features provided by XenCenter, especially the ease of configuring GPU passthrough, but aside from that, I don't care much for the "blackbox" nature of XCP.

With regard to the Linux domU VGA passthrough, I suppose you had the Linux guest configured as HVM guest. I'm wondering how a PV guest would work, and if it could use the proprietary graphics drivers, just like dom0? Actually I never gave it much thought, as I assumed that dom0 was nothing but a privileged PV domU. Did you try a Linux domU as a PV guest?

Yes, GPU passthrough was to an Ubuntu 12.04 HVM guest. Although I've created several PV Linux guests in XCP, I've never tried GPU passthrough with any of them. Based on a Xen wiki page, I was under the impression that GPU passthrough only works with HVM guests. But maybe my impression is wrong. When I get a chance, I'll try again.

I was only able to get GPU passthrough working with the Ubuntu 12.04 HVM guest using whatever default version of Catalyst (not the update) that is found in the Ubuntu 12.04 repository. Considering that the open source drivers work fine with Ubuntu as dom0, I think it's odd that GPU passthrough does not seem to work with Ubuntu 12.04 HVM guest when using the open source Radeon graphics drivers.

Since I hope to get GPU passthrough working with a greater variety of Linux guests (whether with XCP or vanilla Xen), I submitted a "suggestion" to Xen's new uservoice page requesting that the Xen Project work more closely with the developers of open source video drivers to enable GPU passthrough to Linux guests using open source drivers. See http://xenorg.uservoice.com/forums/1...g-open-source-

If you're also interested in getting GPU passthrough working with a greater variety of Linux guests, I hope that you'll consider adding your vote and comments to my suggestion.

Oh, I found this thread while searching for examples of GPU passthrough using KVM. If I'm not mistaken, GPU passthrough using KVM will be much easier using qemu 1.5 combined with kernel 3.9. Daily builds of Ubuntu 13.10 (featuring kernel 3.9) are now available. At present, only qemu 1.4 is available from the Ubuntu 13.10 repository, but hopefully version 1.5 will be available soon. Once it is, Ubuntu 13.10 would seem to be a good prospect for testing GPU passthrough using KVM. I like Xen. But if KVM provides better support for GPU passthough to Linux guests, I'll consider switching to KVM.

[heiko_s]

I didn't mean VGA passthrough with Linux PV guest, but having the PV guest use the driver of dom0 or so. As I said, I never looked into it so it may sound naive.

Regarding kvm, here is a how-to that may be useful: http://www.overclock.net/t/1205216/g...#post_19770787.

I'm almost always using the proprietary drivers, probably out of a habit when using Nvidia cards. I think the gap between AMD proprietary and open source drivers isn't that big as it is with Nvidia. I still would want the best driver available for my graphic card, as it often makes a big difference. Even if its only the power consumption, i.e. switching the card into low power mode when doing easy stuff. I'll have a look at the link you posted, sounds like a good idea.

So my first wish would be that Nvidia adds support for Xen to their closed source drivers, followed by support for VGA passthrough. They could easily do the latter, in fact I have the feeling they prevent it somehow. Have a look at this link: http://www.eevblog.com/forum/project...-counterparts/, specifically here. As you know, the professional Nvidia Quadro etc. cards support VGA passthrough.

[GizmoChicken]

So my first wish would be that Nvidia adds support for Xen to their closed source drivers, followed by support for VGA passthrough. They could easily do the latter, in fact I have the feeling they prevent it somehow.

Yep, I too get the feeling that Nvidia intentionally prevents GPU passthrough. If so, that's just shameful. But hopefully open source drivers, although inferior in many ways, would at least allow for reliable GPU passthrough to Linux guests, which is a feature that the proprietary drivers can't currently boast.

Thanks much for the link to the thread discussing GPU passthrough with KVM. In coming weeks (once qemu 1.5 finds its way into the Ubuntu 13.10 repository), I'll be looking further into the possibility of using KVM as an option for GPU passthrough to Linux guests.

[hannes3]

Hi,

I'm trying to set up a new machine for hardware compability testing and therefore I'd like to have a host machine for VGA passthrough.

My question is now, if anybody has already tried multiple passthrough with different graphic cards such as Nvidia Quadro fx1800 or Quadro 2000 (Nvidia Multi-OS certified)? And if so, is this only possible with Xen or also with Virtual Box or VMWare?

Ideally I would like to set up a different VM for each different graphics card (planned 4 per host).

Thank you in advance for your help!

[sivel27]

hello,

i was successful with pci passthrough following http://http://forums.linuxmint.com/v...?t=112013&f=42
i was banging my head trying to figure out why i was getting error 22 when starting the vm, only to realize the pciback script i had wasnt grabbing the 2nd vga quickly enough.

virtually same fps in games, which is good for my son, since thats the only reason i still use windows.

thanks,
mike

[adam-9]

Can anyone please confirm that Virtual Box really is capable of VGA Passthrough, as advertized on manual?

I heavily use VirtualBox already.

[pendulous]

Can anyone please confirm that Virtual Box really is capable of VGA Passthrough, as advertized on manual?

I heavily use VirtualBox already.

Doesn't seem so, it's still experimental.

According to the manual this is only supported on Linux hosts:

http://www.virtualbox.org/manual/ch0...pcipassthrough

[EDIT - I also confirmed with the VBox dev team. This is not supported (and still experimental even on Linux)]

Source:
http://superuser.com/questions/66383...-in-virtualbox
https://forums.virtualbox.org/viewtopic.php?f=7&t=56568



I know VMWare supports it. Personally, haven't gotten into HyperV that much, since my systems are still LGA775's, once I obtain Skylake I'm all in.

[tuxinteger]

I can't do away with *******, but I hate dual-boot. I also need native (or near-native) graphics support in the Windows VM.

In the end I chose Xen to host Linux and a Windows 7 VM which uses a dedicated graphics card for native graphics performance. It works extremely well, with what I consider top-notch performance that doesn't stand (much) behind a native Windows installation on bare metal.

In fact, I'm so thrilled about it that I wonder why not every dual-booter is switching to virtualization. (I'm actually not that surprised since it was quite challenging to get it working.)

Here my questions:

Has anybody tried VGA passthrough?

If yes, which hypervisor/method did you use (Xen, KVM, VMware, etc.)?

How easy or difficult was it?

In the end I would like to know if there are perhaps better or easier ways to get it working. Thanks in advance for your feedback!

#
Successful with PCI & USB passthrough ,using hd7870 and quadro fx1600,passing through the hd7870 card ,GL & DX
performance is only 4% less than win8 ,but seems to out perform win7 baremetal.

Not using KVM ,using 2 monitors ,2 kb's & mice,on different usb controllers hubs,seems less troublesome and better perf.

The primary xen monitor switches over to the domu guest on hvm startup,so i still have access to the host ubuntu machine
on the 2nd monitor ,i prefer this setup to a kvm.

Hardware -Mainboard Asrock ext4 z77,xeon 1200 cpu 4 core -8 threads,xen dom0 working on 2 cores fine.

An ssd would be favourable to increase o/all performance.

I based the HVM method on ubuntu 13.10 ppa of Xen ( 4.3) on the linux mint reference with kernel mode and
Runlevel pciback script .I found the manual script to pass throug hdevices in RL20 to halt the host if it wasnt loaded
between runlevel 19&20 -see ref to this in pciback scripts in the linux mint reference in this thread
http://forums.linuxmint.com/viewtopic.php?t=112013

The grub loader settings are critical for the machine performance if ram memory is limited ,ie 8gb ,16gb is preferable if
you plan to use both the host and the guest simultaneously,as compiz can be intensive at times,with 8gb ram i have to
use the lighter desktop to work on the host and guest screens /machines.

Warning : Do not isntall ccc or the whole amd package with ccc into the machine as it will give a nasty bs/od,extract and install
manually !.

Heres my happy grub default ;

GRUB_DEFAULT="Xen 4.3-amd64"
# GRUB_HIDDEN_TIMEOUT="0"
# GRUB_HIDDEN_TIMEOUT_QUIET="true"
GRUB_TIMEOUT="10"
GRUB_DISTRIBUTOR="`lsb_release -i -s 2> /dev/null || echo Debian`"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash # took out nomodeset as issues with display on quadro card"
#
GRUB_CMDLINE_LINUX_DEFAULT="radeon.blacklist=1 quiet splash"
# above line prev had "quiet splash intel_iommu=on"
# GRUB_CMDLINE_LINUX="apparmor=0" #took out again poss cause high disk access a
# testing below issues with disk access and host mem
# GRUB_CMDLINE_XEN="intel_iommu=on dom0_mem=512M,max:1024M dom0_max_vcpus=2 dom
# if the below line isnt in the perf is poor on host
GRUB_CMDLINE_XEN="iommu=1 dom0_max_vcpus=2 dom0_vcpus_pin"


It's great not to have to reboot for win work & i Havent tried w8 as yet.


Cons ; -No real issues.


1- Dom0 doesnt seem to release memory back to the host well after the HVM Domu is shutdown,still working on this as max mem & static mem settings do not help.
2- When using pci passthrough the domain guest cannot be saved.

#

[heiko_s]

Can anyone please confirm that Virtual Box really is capable of VGA Passthrough, as advertized on manual?

I heavily use VirtualBox already.

I don't think so. AFAIK at the moment only Xen, kvm, and VMware support VGA passthrough.

Sorry for the late reply.

[heiko_s]

@tuxinteger: Thanks for your detailed answer.

I based the HVM method on ubuntu 13.10 ppa of Xen ( 4.3) on the linux mint reference with kernel mode and
Runlevel pciback script .I found the manual script to pass throug hdevices in RL20 to halt the host if it wasnt loaded
between runlevel 19&20 -see ref to this in pciback scripts in the linux mint reference in this thread
http://forums.linuxmint.com/viewtopic.php?t=112013

Sorry, I don't follow you here. Can you explain?

By the way, the method of binding the graphics card to pciback has changed - check again the how-to, step 11. Instead of the pciback script it use now:

echo "xen-pciback passthrough=1 hide=(02:00.0)(02:00.1)" >> /etc/initramfs-tools/modules
update-initramfs -k all -c

for the graphics card (and/or any PCI device that should be bound to pciback during the PC boot process).