Tag Archives: Windows 10

KVM with vga passthrough in arch linux

I’ve once again switched from Proxmox to Arch Linux for my desktop machine. Both use KVM so it’s really just a matter of using the different VM manager syntax (virt-manager vs qm.) I used my notes from my previous stint with Arch, my article on GPU Passthrough in Proxmox as well as a thorough reading of the Arch wiki’s PCI Passthrough article.

Enable IOMMU

Configure GRUB to load the necessary iommu modules at boot. Append amd_iommu=on iommu=pt to the end of GRUB_CMDLINE_LINUX_DEFAULT (change accordingly if you have Intel instead of AMD)

sudo vim /etc/default/grub
...
GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 amd_iommu=on iommu=pt"

Run update-grub

sudo update-grub

Reserve GPU for VFIO

Reserve the GPU you wish to pass through to a VM for use with the vfio kernel driver (so the host OS doesn’t interfere with it)

  1. Determine the PCI address of your GPU
    1. Run lspci -v and look for your card. Mine was 01:00.0 & 01:00.1. You can omit the part after the decimal to include them both in one go – so in that case it would be 01:00
    2. Run lspci -n -s <PCI address from above> to obtain vendor IDs.
      Example :
      lspci -n -s 01:00
      01:00.0 0300: 10de:1b81 (rev a1)
      01:00.1 0403: 10de:10f0 (rev a1)
  2. Assign your GPU to vfio driver using the IDs obtained above.
    Example using above IDs:
    echo "options vfio-pci ids=10de:1b81,10de:10f0" >> /etc/modprobe.d/vfio.conf

Reboot the host to put the kernel / drivers into effect.

Configure virt-manager

Install virt-manager, dnsmasq & libvirtd:

pacman -Sy libvirtd virt-manager dnsmasq
sudo systemctl enable libvirtd
sudo systemctl start libvirtd

Configure Networking

Assuming you’re using network manager for your connections, create a bridge (thanks to ciberciti.biz & the arch wiki for information on how to do so.) Replace interface names with ones corresponding to your machine:

sudo nmcli connection add type bridge ifname br0 stp no
sudo nmcli connection add type bridge-slave ifname enp4s0 master br0 
sudo nmcli connection show
#Make note of the active connection name
sudo nmcli connection down "Wired connection 2" #from above
sudo nmcli connection up bridge-br

Create a second bridge bound to lo0 for host-only communication. Change IP as desired:

sudo nmcli connection add type bridge ifname br99 stp no ip4 192.168.2.1/24
sudo nmcli connection add type bridge-slave ifname lo master br99 
sudo nmcli connection up bridge-br99

Configure VM

Initial configuration

When creating the passthrough VM, make sure chipset is Q35.

Set the CPU model to host-passthrough (type it in, there is no dropdown for it.)

When adding disks / other devices, set the device model to virtio

Add your GPU by going to Add Hardware and finding it under PCI Host Device.

Windows 10 specific tweaks

If your passthrough VM is going to be windows based, some tweaks are required to get the GPU to work properly within the VM.

Ignore MSRs (blue screen fix)

Later versions of Windows 10 instantly bluescreen with kmode_exception_not_handled unless you pass an option to ignore MSRs. Add the kvm ignore_msrs=1 option in /etc/modprobe.d/kvm.conf to do so. Optionally add the report_ignored_msrs=0 option to squelch massive amounts of kernel messages every time an MSR was ignored.

echo "options kvm ignore_msrs=1" >> /etc/modprobe.d/kvm.conf
#Optional - ignore kernel messages from ignored MSRs
echo "options kvm report_ignored_msrs=0" >> /etc/modprobe.d/kvm.conf

Reboot to make those changes take effect.

NVIDIA Code 43 workaround

Use the virsh edit command to make some tweaks to the VM configuration. We need to hide the fact that this is a VM otherwise the GPU drivers will not load and will throw Error 43. We need to add a vendor_id in the hyperv section, and create a kvm section enabling hidden state, which hides certain CPU flags that the drivers use to detect if they’re in a VM or not.

sudo virsh edit <VM_NAME>

<features>
	<hyperv>
		...
		<vendor_id state='on' value='1234567890ab'/>
		...
	</hyperv>
	...
	<kvm>
	<hidden state='on'/>
	</kvm>
</features>

Optimize CPU

If you operate on a multi-core system such as my AMD Ryzen Threadripper the you will want to optimize your CPU core configuration in the VM per the CPU Pinning section in the Arch Wiki

Determine your CPU topology by running lscpu -e. The important things to look for are the CPU number and core number. On my box, it looks like this:

CPU NODE SOCKET CORE L1d:L1i:L2:L3 ONLINE MAXMHZ MINMHZ
0 0 0 0 0:0:0:0 yes 3400.0000 2200.0000
1 0 0 1 1:1:1:0 yes 3400.0000 2200.0000
2 0 0 2 2:2:2:0 yes 3400.0000 2200.0000
3 0 0 3 3:3:3:0 yes 3400.0000 2200.0000
4 0 0 4 4:4:4:1 yes 3400.0000 2200.0000
5 0 0 5 5:5:5:1 yes 3400.0000 2200.0000
6 0 0 6 6:6:6:1 yes 3400.0000 2200.0000
7 0 0 7 7:7:7:1 yes 3400.0000 2200.0000
8 0 0 8 8:8:8:2 yes 3400.0000 2200.0000
9 0 0 9 9:9:9:2 yes 3400.0000 2200.0000
10 0 0 10 10:10:10:2 yes 3400.0000 2200.0000
11 0 0 11 11:11:11:2 yes 3400.0000 2200.0000
12 0 0 12 12:12:12:3 yes 3400.0000 2200.0000
13 0 0 13 13:13:13:3 yes 3400.0000 2200.0000
14 0 0 14 14:14:14:3 yes 3400.0000 2200.0000
15 0 0 15 15:15:15:3 yes 3400.0000 2200.0000
16 0 0 0 0:0:0:0 yes 3400.0000 2200.0000
17 0 0 1 1:1:1:0 yes 3400.0000 2200.0000
18 0 0 2 2:2:2:0 yes 3400.0000 2200.0000
19 0 0 3 3:3:3:0 yes 3400.0000 2200.0000
20 0 0 4 4:4:4:1 yes 3400.0000 2200.0000
21 0 0 5 5:5:5:1 yes 3400.0000 2200.0000
22 0 0 6 6:6:6:1 yes 3400.0000 2200.0000
23 0 0 7 7:7:7:1 yes 3400.0000 2200.0000
24 0 0 8 8:8:8:2 yes 3400.0000 2200.0000
25 0 0 9 9:9:9:2 yes 3400.0000 2200.0000
26 0 0 10 10:10:10:2 yes 3400.0000 2200.0000
27 0 0 11 11:11:11:2 yes 3400.0000 2200.0000
28 0 0 12 12:12:12:3 yes 3400.0000 2200.0000
29 0 0 13 13:13:13:3 yes 3400.0000 2200.0000
30 0 0 14 14:14:14:3 yes 3400.0000 2200.0000
31 0 0 15 15:15:15:3 yes 3400.0000 2200.0000

From the above output I see my CPU core 0 is shared by CPUs 0 & 16, meaning CPU 0 and CPU 16 (as seen by the Linux kernel) are hyperthreaded to the same physical CPU core.

Especially for gaming, you want to keep all threads on the same CPU cores (for multithreading) and the same CPU die (on my threadripper, CPUs 0-7 reside on one physical die, and CPUs 8-15 reside on the other, within the same socket.)

In my case I want to dedicate one CPU die to my VM with its accompanying hyperthreads (CPUs 0-7 & hyperthreads 16-23) You can accomplish this using the virsh edit command and creating a cputune section (make sure you have a matching vcpu count for the number of cores you’re configuring.) Also edit CPU mode with the proper topology of 1 socket, 1 die, 8 cores with 2 threads.

sudo virsh edit <VM_NAME>

<domain type='kvm'>
  ...
  <vcpu placement='static'>16</vcpu>  
  <cputune>
    <vcpupin vcpu='0' cpuset='0'/>
    <vcpupin vcpu='1' cpuset='16'/>
    <vcpupin vcpu='2' cpuset='1'/>
    <vcpupin vcpu='3' cpuset='17'/>
    <vcpupin vcpu='4' cpuset='2'/>
    <vcpupin vcpu='5' cpuset='18'/>
    <vcpupin vcpu='6' cpuset='3'/>
    <vcpupin vcpu='7' cpuset='19'/>
    <vcpupin vcpu='8' cpuset='4'/>
    <vcpupin vcpu='9' cpuset='20'/>
    <vcpupin vcpu='10' cpuset='5'/>
    <vcpupin vcpu='11' cpuset='21'/>
    <vcpupin vcpu='12' cpuset='6'/>
    <vcpupin vcpu='13' cpuset='22'/>
    <vcpupin vcpu='14' cpuset='7'/>
    <vcpupin vcpu='15' cpuset='23'/>
  </cputune>
  ...
  <cpu mode='host-passthrough' check='none'>
    <topology sockets='1' dies='1' cores='8' threads='2'/>
  </cpu>
  ...
</domain>

I found here I’ve been doing the vcpupins wrong – apparently the better way to do it is to do primary CPU thread, then hyperthread CPU. I had been doing all the main CPUs first, then their hyperthreads. Once I change to the every-other configuration stuttering disappeared.

Update 6/28/20: Additional tuning since I was having some stuttering and framerate issues

Dedicate CPUs to the VM (host will not use them) – append isolcups, nohzZ_full & rcu_nocbs kernel parameters into /etc/default/grub

...
GRUB_CMDLINE_LINUX_DEFAULT=... isolcpus=0-7,16-23 nohz_full=0-7,16-23 rcu_nocbs=0-7,16-23
...

Update grub:

sudo grub-mkconfig -o /boot/grub/grub.cfg

Reboot, then check if it worked:

cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-linux root=/dev/mapper/arch-root rw loglevel=3 amd_iommu=on iommu=pt isolcpus=0-7,16-23 nohz_full=0-7,16-23 rcu_nocbs=0-7,16-23
taskset -cp 1
pid 1's current affinity list: 8-15,24-31

You can still tell programs to use the CPUs the VM has manually with the taskset command:

chrt -r 1 taskset -c <cores to use> <name of program/process>

Change CPU frequency setting to use performance mode:

sudo pacman -S cpupower
sudo cpupower frequency-set -g performance

Profit

I’m very pleased with my current setup. It works well!

proxmox 6 NVIDIA GPU passthrough fix

I upgraded to ProxMox 6.0 and to my dismay my Windows VM suddenly began receiving the dreaded Code 43 error. After much digging I finally found this post on the ProxMox forums which outlines what needs to happen.

In my case, all I needed to do was tweak my machine type. There is no GUI option to do this, so it had to be done in the command line:

qm set <VM_ID> -machine pc-q35-3.1

That was all it took!

The forum also suggested a few other things if that didn’t work. I didn’t end up needing them but I’ll put them here in case it’s helpful:

Add args to your VM config file:

args: -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=NV43FIX,kvm=off'

Add a few options to the CPU line:

cpu: host,hidden=1,flags=+pcid,hv-vendor-id=proxmox

With the above settings I also discovered there is no need to have x-vga=on anymore. This allows you to have both the regular VM console and your graphics card if you so desire.

sideload Gears of War 5 on Windows 10

Sideloading Gears 5 is similar to sideloading Gears 4. You need to grab the URL the store is using to download the game with a proxy tool like fiddler, then download that URL with a download manager.

Gears 5 is an msixvc file instead of an eappx file. You can still install this via the add-appxpackage command.

I ran into issues trying to run add-appxpackage from a network drive. It worked after copying to a local drive and running the command again.

Why go through the trouble? Because the Microsoft store’s DRM is so bad it requires complete re-installs when anything goes wrong. This is very annoying for those of us on less than gigabit internet connections trying to reinstall a 60+ GB game.

Installing Gears of War 4 in Windows 10

Installing Gears of War 4 on Windows can only be described as a hellish nightmare. Here are my notes on how I finally got it to install and run.

  • Download file with fiddler and a download accelerator, as outlined here:

[GUIDE v2.0] How to download install package for Windows Store games (bypass Store download issues or for install on another PC) from pcgaming

  • Once you have the file, begin installing / downloading the game from the Windows store. Get several hundred MB / a few GB, then pause download.
  • Open powershell (no need to be an admin) and run the following:
    • Add-AppxPackage -path "<PATH TO GEARS FILE>"

After finish, close windows store and re-open, launch from there.

You may need to repeat removal and installation process many times, but now that you have the EAPPX file, it should be much less painful.

Powershell equivalent of “find -exec”

I recently found myself on a Windows 10 system needing to do the equivalent of “find . -name *.mdi -exec mdiconvert -source {} -log log.txt \;” I knew what to do instantly on a Unix system, not so on a Windows system

I finally figured it out and am now writing it down because I know I’ll forget! Thanks to these several sites for pointing me in the right direction.

  • Get-ChildItem is the find equivalent
    • -Filter is the -name equivalent
    • -Recurse must be specified otherwise it only looks in the one directory
  • % is an alias for “ForEach-Object
  • Put the command you want run in brackets {}
  • Put an ampersand in front of the command you wish to run so you can properly pass arguments containing dashes
  • $_.FullName turns the powershell object into a text string (which my command required.) FullName is the full path of the item found with Get-ChildItem
    • $_ is the rough equivalent of find’s {} (the item that was found)

The command I ended up using is below (find any .mdi files and use Microsoft’s mdi2tif utility to convert the result to .tif files)

Get-ChildItem "C:\Users" -Recurse -Filter *.mdi | % { & 'C:\Program
Files (x86)\modiconv\MDI2TIF.EXE' -source $_.FullName -log log.txt }

Sabrent USB AU-MMSA microphone not working in Windows 10

I recently installed Windows 10 for my gaming VM and discovered that my microphone was no longer working. All the drivers were properly installed and sound worked fine, but there was nothing coming from the microphone.

My gaming VM uses a Sabrent USB External Stereo Sound Adapter model  AU-MMSA passed through for sound. This was most perplexing because it worked in other OSes, but not Windows 10.

After much digging I finally found this youtube video which outlined the problem: Microphone permissions to the system. The hybrid that Windows 10 is between Store apps / permissions and regular desktop apps reminds me of Windows ME. An unholy union.. terrible.

At any rate, the fix is to grant the system permission to use its own microphone, un-granting it first if necessary.

Go to Start / Settings (little gear icon in bottom left) then search for Microphone Privacy Settings. Click the big Change button beneath “Microphone access for this device is on”  at the top of that screen. Change the toggle to “off”, then change it back to “on” again. This fixed my microphone.

 

Windows VM with GTX 1070 GPU passthrough in ProxMox 5

I started this blog four years ago to document my highly technical adventures – mainly so I could reproduce them later. One of my first articles dealt with GPU passthrough / virtualization. It was a complicated ordeal with Xen. Now that I’ve switched to KVM (ProxMox) I thought I’d give it another go. It’s still complicated but not nearly as much this time.

To get my Nvidia GTX 1070 GPU properly passed through to a Windows VM hosted by ProxMox 5 I simply followed this excellent guide written by sshaikh. I will summarize what I took from his guide to get my setup to work.

  1. Ensure VT-d is supported and enabled in the BIOS
  2. Enable IOMMU on the host
    1. append the following to the GRUB_CMDLINE_LINUX_DEFAULT line in /etc/default/grub
      intel_iommu=on
    2. Save your changes by running
      update-grub
  3. Blacklist NVIDIA & Nouveau kernel modules so they don’t get loaded at boot
    1. echo "blacklist nouveau" >> /etc/modprobe.d/blacklist.conf
      echo "blacklist nvidia" >> /etc/modprobe.d/blacklist.conf
    2. Save your changes by running
      update-initramfs -u
  4. Add the following lines to /etc/modules
    vfio
    vfio_iommu_type1
    vfio_pci
    vfio_virqfd
  5. Determine the PCI address of your GPU
    1. Run
      lspci -v

      and look for your card. Mine was 01:00.0 & 01:00.1. You can omit the part after the decimal to include them both in one go – so in that case it would be 01:00

    2. Run lspci -n -s <PCI address> to obtain vendor IDs. Example :
      lspci -n -s 01:00
      01:00.0 0300: 10de:1b81 (rev a1)
      01:00.1 0403: 10de:10f0 (rev a1)
  6. Assign your GPU to vfio driver using the IDs obtained above. Example:
    echo "options vfio-pci ids=10de:1b81,10de:10f0" > /etc/modprobe.d/vfio.conf
  7. Reboot the host
  8. Create your Windows VM using the UEFI bios hardware option (not the deafoult seabios) but do not start it yet. Modify /etc/pve/qemu-server/<vmid>.conf and ensure the following are in the file. Create / modify existing entries as necessary.
    bios: ovmf
    machine: q35
    cpu: host,hidden=1
    numa: 1
  9. Install Windows, including VirtIO drivers. Be sure to enable Remote desktop.
  10. Pass through the GPU.
    1. Modify /etc/pve/qemu-server/<vmid>.conf and add
      hostpci0: <device address>,x-vga=on,pcie=1. Example

      hostpci0: 01:00,x-vga=on,pcie=1
  11. Profit.

Troubleshooting

Code 43

I received the dreaded code 43 error after installing CUDA drivers. The workaround was to add hidden=1 to the CPU option of the VM:

cpu: host,hidden=1

Blue screening when launching certain games

Heroes of the Storm and Starcraft II would consistently blue screen on me with the following error:

kmode_exception_not_handled

The fix as outlined here was to create /etc/modprobe.d/kvm.conf and add the parameter “options kvm ignore_msrs=1”

echo "options kvm ignore_msrs=1" > /etc/modprobe.d/kvm.conf

Update 4/9/18: Blue screening happens to Windows 10 1803 as well with the error

System Thread Exception Not Handled

The fix for this is the same – ignore_msrs=1

GPU optimization:

Give as many CPUs as the host (in my case 8) and then enable NUMA for the CPU. This appeared to make my GTX 1070 perform better in the VM – near native performance.

Reboot a windows system remotely

I recently came across the need to reboot my Windows 10 workstation remotely. I couldn’t RDP into the box  – it would stay stuck on the disclaimer splash screen. There was an OK button but it did nothing when clicked.

My solution was to initiate a reboot command from another Windows PC on the same network as my Windows 10 workstation. I figured out how to do so thanks to this article.

To remotely reboot yourself, log onto another Windows box and open up a command shell with an account that has administrative permissions on the machine you want to reboot. Then, issue this command:

shutdown -r -f -m \\<remote machine name> -t 30 -c "<message>"

The above command forces a reboot command (shutdown -r -f) on the remote machine (-m \\machine name), causes a countdown timer for the number of seconds specified (-t 30) and displays a message on the screen (-c “message”).

It solved my issue and was pretty easy to do. Handy.