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

[heiko_s]

Some updates from my side. I've successfully tested Ubuntu 14.04 Beta2 with Xen 4.4 and an AMD 6450 card for VGA passthrough (AMD 7770 for dom0) using the xl toolstack.

It looks like Xen 4.4 and the 3.13 kernel have improved things a lot over previous releases, particularly with passing through AMD cards. There has been a issue hunting AMD GPU cards when using the xl toolstack that would either cause performance loss or prevent a reboot of the domU, or even crash the dom0. With Ubuntu 14.04 and Xen 4.4 I wasn't able to reproduce this issue and everything worked as it should.

The xl toolstack still requires the old qemu-xen-traditional as device model version in the domU configuration file, the new qemu-xen (upstream) would allow installation of a Windows guest but not support VGA passthrough.

Some of the software updates on older Ubuntu or Linux Mint releases could break VGA passthrough support when using the xm toolstack - the "error 22" problem, but in this case it seems like a new bug (the old "error 22" bug was fixed long ago). Since xm is deprecated and Xen 4.4 works well with xl, it doesn't make much sense to beat a dead horse.

While Xen and xl worked fine with Ubuntu 14.04, I discovered some nasty bugs in other applications:

1. xtightvncviewer: doesn't allow empty password strings . The workaround is to define a 6-8 letter password in the /etc/xen/guest.cfg file.
2. vnc4viewer: It crashes randomly after startup. At some point I couldn't get it to start up at all.
3. Ubuntu 14.04 detects both VGA cards and automatically sets up dual screen, which is not what I want. In addition I had problems installing the proprietary fglrx driver under Xen. To solve problem #1 I removed the second VGA card before installing Ubuntu, and only after I created an initramfs with the (not yet installed) graphics card bound to pciback did I shut down and install the card.
Problem #2 requires shutting down the X server and running a initialisation routine of the AMD driver to set up a configuration file for the screen(s).

More on that here.

[Nickolai_Leschov]

I would like to set up VGA passthrough when I will be reinstalling Ubuntu on ThinkPad X200 (Core 2 Duo SL9400 CPU). The machine supports VT-x, but not VT-d. The next model, X201, seems to have the necessary technology in CPUs like i7-620LM. Can I do it or is it a show-stopper?

I thought of using Ubuntu 14.04 64-bit with KVM as dom0 and Ubuntu and Windows as guests.

Does it make sense?

[ubeauty]

For anyone looking through the forums trying to get VGA passthrough tow ork with XEN (I've only worked with vanilla xen 4.4.x & dom0 ubuntu 14.4) my big conclusion is a simple one - VGA passthrough won't work with HVM's allocated over 2GB of RAM but will work with HVM's with less - beautifully.

There appear to be patches and modules that may fix the issue with 4.4, but for me not an acceptable approach for a production machine, so I will wait for XEN 4.5 and hope the memory/vga passthrough issue is resolved by then. 4.5 is expected in December according to this: http://wiki.xenproject.org/wiki/Xen_...or_Roadmap/4.5

Seems like our archlinux brothers are getting some success with compiling xen 4.5 https://bbs.archlinux.org/viewtopic.php?id=183994 and VGA passthrough.

[redger]

I have been using VGA passthrough for the last 5 months or so. Starting with Arch using the instructions here https://bbs.archlinux.org/viewtopic.php?id=162768 and referene information here http://vfio.blogspot.com.au/
Then I moved to Ubuntu Trusty and am happily running a variety of guests using KVM - both Ubuntu and Windows 7 guests.
VGA passthrough works, performance is great - I run 3 1080P monitors for gaming on a Windows 7 guest with the following hardware
-CPU Intel 4670 (use the IGP for host graphics)
-Motherboard Asrock Z87-Extreme 6
-RAM 16GB
-GPU AMD HD6950 (used by Windows to drive triple monitors)

-KUbuntu Trusty
-Libvirt / Virt-Manager (works nicely but requires some reconfiguration, so I created a simple shell program fpr the Windows guest and attached that to the KDE menu, then run Ubuntu guests using Virt-Manager)

Basic steps are to
-Follow the Grub and VFIO setup as described in the Arch forum.
-Patch the kernel (and update the Config as recommended)
-Allocate the storage (LVM partition in raw format recommended)
-Create the necessary Qemu command (you will need to run this as root)

For host based sound I found the best results are achieved with Alsa rather than Pulse (pulse induced lag which is not good for gaming) BUT the easiest is to purchase a cheap add-in USB card and a cheap USB sound device.

I tried Xen, the earlier versions work but are much slower for gaming than KVM and KVM continues to improve

[Germano_Cesari]

I've succesfully set up VGA passthrough with a Quadro 4000 and everything is working great.

My motherboard is a SuperMicro H8DGi/F with 2x opterons 6140, an onboard Matrox G200 and a discrete Quadro 4000. On guest startup xl complains the Quadro, sound device, usb controller, keyboard and mouse dont support FLR, but keeps on going just fine anyway...

Dom0 is Ubuntu server 14.04 LTS with vanilla xen 4.4
DomU is HVM win7 Pro x64, NV driver latest quadro

I have 2 monitors, one is connected to the Quadro, the other to the onboard G200, Bios have been set to boot from the Matrox G200 and the integrated Matrox is the one I use for Dom0 control.
I had to setup the Quadro as the primary adapter, (gfx_passthrough = 1) otherwise the NV driver in win7 would randomly (and pretty easily) crash even after trivial operations like a window resize. If the Quadro is the primary adapter, there is no problem whatsoever.

The annoying part of having it as the primary adapter is that it boots from the Matrox (and the connected monitor), and keeps on using the onboard Matrox until the windows logo shows up, from that point on it switches to the Quadro.
Keyboard and mouse also are PCI passed-through only after the window logo shows up.
This is not a problem per se, since I dont use more than a single VM at once, it is just annoying because a) Im left with no Dom0 screen, and b) the onboard Matrox is not reset after guest shutdown, so I have to SSH to get control of the system or type without seeing anything.

Note that the onboard Matrox is never referenced in the guest configuration file, I dont get why xen takes it anyway..

Is there a way to avoid switching to the integrated Matrox at first, or at least to reset it somehow? I tried difefrent things (like echo 1 > /sys/bus/pci/devices/device/reset) but with no luck..

[Germano_Cesari]

For anyone looking through the forums trying to get VGA passthrough tow ork with XEN (I've only worked with vanilla xen 4.4.x & dom0 ubuntu 14.4) my big conclusion is a simple one - VGA passthrough won't work with HVM's allocated over 2GB of RAM.

I strongly disagree with your conclusion, VGA passthrough with vanilla xen 4.4 + Dom0 Ubuntu 14.04 is working great for me for a HVM win7 x64 DomU with 4/8 vcpu + 8GB of RAM, see my previous post

[hurenkam]

Almost two years have passed, since my earlier post. Recently I've been experimenting with a more recent kernel & hypervisor (Ubuntu 14.04.1 / Xen 4.4), however I found this to be rather unstable.
Looking a bit beyond Xen, I found several reports of KVM/VFIO being quite stable, and capable of doing proper VGA passthrough, so I thought I'd give that a try.
And I must say, I'm happily surprised, KVM is proving to be even more stable than my previous Xen 4.2 setup, and although I had some drivers behaving weird in one of my VMs, the host is rock stable.

Host:
My hardware is still the same: Intel i7 860, Asus P7P55D Evo main board, Asus EAH4350 silent graphics cards (2x).
One caveat though: I am unable to use the primary graphics card for VGA passthrough using qemu/kvm, it will lock-up the machine. Hence i added another graphics card, so that the 2 4350's can be used in the VMs.
Running a recent Arch linux, with Qemu v2.1.2, kernel 3.17.6-1-ARCH.

VMs (am able to run any two of these in parallel, each passed a graphics card and usb card, the third can run in parallel using vnc):
1) Arch linux runs fine with default opensource radeon driver. No issues installing, virtio-net, virtio-block and balloon is all functioning fine.
2) Windows 8, had some issues getting it to update to recent version, but eventually managed. Upgrading to 8.1 fails, perhaps I need to play with the machine layout to get it to work. Some info on the web seems to suggest i should install catalyst drivers to get it to upgrade properly, i haven't tried that yet. Installed redhat virtio-net, virtio-block and balloon drivers, all seems to work fine.
3) Gave OSX Mavericks a try, and much to my surprise was able to run it (after retrieving the OSK keys from my macbook, and providing it on the command line). To run it with proper radeon, usb & network support requires downloading and installing some kext files. I managed to get almost all devices to work, with the exception of my intel hd audio card.

Would be great if i could use the Primary VGA card as well, Xen was able to pass it through, I'm not sure what's preventing Qemu/KVM from doing so.

[hurenkam]

Would be great if i could use the Primary VGA card as well, Xen was able to pass it through, I'm not sure what's preventing Qemu/KVM from doing so.

Managed to get the primary card working too, it requires booting in text-only mode, passing 'nomodeset' and 'nofb' to the linux kernel, blacklisting the radeon driver, and switching grub to use text mode only.

[redger]

I created a new post to describe how to establish a UEFI based Windows VM using KVM
http://ubuntuforums.org/showthread.p...9#post13235279

I've found this to produce the best overall result for me. Easy to manage with the gui, stable, secure and doesn't require any kernel patches (unlike the method I was previously using which required VGA-arbiter and other patches)

Note that (a) the host need not be booted via UEFI and (b) even older AMD graphics cards can be "enhanced" for UEFI boot

[jamel-maison]

Hello everyone,

I've just want to take you aware of my little success to give hopeness to others.

VGA-Passthrough became plug and play with current version of ubuntu and kvm

What I did :
- buying an HP DC7900 with 8 Gb of RAM and E8400 CPU (very low cost dc7800 may works too) and a radeon 5450 1G.
- configuring machine to expose vt-d (activating MEBx in bios, rebooting, Ctrl+P to enter MEBx, configuring vt-d, reboot, activating vt-d in bios, reboot)
- configuring machine to boot on integrated video and graphic card put in in slot2 (4X)
- installing ubuntu 14.04
- installing kvm and virt-manager (and all that come with) from depot
- installing W7_64 in VM in VNC window, stopping it
- modifiying VM in virt-manager to add graphic card and usb device
- booting VM and installing driver
- that all folks. I'd just tried hot pursuite unleashed and very impressive. Rate from windows at 4,1, exactely equal as native windows on this machine.

Rest to make VM work with primary card and in slot 1 (16x). I will change cpu from 2 to 4 cores and try with 16Go RAM. When all will works, I will put VM on SSD to speedup running.

And voila. Next news when I will go ahead.