Windows 11 on Chromebook (Linux 'Crostini' container)

Optimising performance

Running Windows 10 on my Lenovo Flex 5 (i5 tenth generation) was a bit slow, to say the least. I was keen to improve the performance of Windows 11 on my Asus CX9. The guide from farmerbb in ‘QEMU/KVM virt-manager vm very slow’ was particularly helpful. I didn’t actually use Leducc’s article ‘Improving the performance of a Windows Guest on KVM/QEMU’, but it looks pretty informative, too.

Like farmerbb, I applied all possible Hyper-V enlightenments.

<hyperv>
  <relaxed state='on'/>
  <vapic state='on'/>
  <spinlocks state='on' retries='8191'/>
  <vpindex state='on'/>
  <synic state='on'/>
  <stimer state='on'>
    <direct state='on'/>
  </stimer>
  <reset state='on'/>
  <frequencies state='on'/>
  <reenlightenment state='on'/>
  <tlbflush state='on'/>
  <ipi state='on'/>
</hyperv>

I disabled all timers except for hypervclock. Like farmerbb, and unlike some other guides, I left hpet disabled.

<clock offset='localtime'>
  <timer name='rtc' present='no' tickpolicy='catchup'/>
  <timer name='pit' present='no' tickpolicy='delay'/>
  <timer name='hpet' present='no'/>
  <timer name='kvmclock' present='no'/>
  <timer name='hypervclock' present='yes'/>
</clock>

One particular caution I have with farmerbb’s guide is that the CPU pinning settings is specifically for his 6-core CPU, so blind copying of those settings will probably mismatch virtual cores e.g. matching core 1 to core 6. Some other articles mention getting the pinning setting wrong is a likely cause of worse performance. Currently, I have set any cCPU pinning.

I downloaded the Windows virtio drivers as suggested by farmerbb. I placed both my Windows and virtio driver ISO (currently named ‘virtio-win-0.1.240.iso’) into the Crostini ‘normal’ user’s Download directory. Trying to install with those ISOs from a directory outside the Crostini directories did not work, for some reason QEMU managed to lose contact with the files during the install process. Unlike the QEMU XML snippet provided by farmerbb, I did not provide the address, as this appears to be auto-generated, and did not set cache. Note that the disk file is stored in the libvirt directory.

<disk type='file' device='disk'>
  <driver name='qemu' type='qcow2' io='threads' discard='unmap' iothread='1' queues='6'/>
  <source file='/var/lib/libvirt/images/win11.qcow2'/>
  <target dev='vda' bus='virtio'/>
</disk>

Standard users cannot access the libvirt directory!

I followed Method 1 in the Ostechnix article!). As sudo, I edited the /etc/libvirt/qemu.conf file, adding:

user = "myusername"
group = "libvirt"

Then restarting the libvirtd service, and making sure my regular user is part of the libvirt group.

sudo systemctl restart libvirtd
sudo usermod -a -G libvirt $(whoami)

Resizing Windows 11 guest window, Spice guest tools, Secure boot

I installed Spice guest tools, but it didn’t seem to be working, especially window resizing. The eventual solution was provided by ‘Wind Slightly’ in the post ‘virt-manager guest resize not working’.

It appears that the secure boot option in the boot manager/BIOS does not allow the spice guest tools to work. I entered the QEMU Windows 11 machine BIOS (I think by pressing the Escape key during boot) and disabled secure boot. After that, windows resize worked properly.

Inactive network (as seen in virt-manager)

For some reason, the network became disabled, as could be seen in the virt-manager GUI.

I was able to restart the network with the instructions included in a post written by elattlat

sudo virsh net-autostart default
sudo virsh net-start default

Sharing files between Windows (in Crostini) and Linux (in Crostini)

This is difficult, and nowhere near as easy as using Virtualbox.

One ‘trick’ is to use the Remmina remote desktop client, and share a folder using the Remmina GUI. My particular Remmina client is not quite as pretty as shown in the stackexchange post. A share folder could only be specified in a saved configuration, and the name of the share folder could only be specified by text (no directory chooser!). In my case, the name of the share folder was a folder in the user’s home directory.

I enabled remote desktop protocol in Windows using the guide in groovypost. The server name I chose in Remmina was the IP address of the virtual machine (as can be seen in the virt-manager). The username I set to my Windows login (e.g. myusername@outlook.com). One tricky thing with using the Windows login is that my ability to use passwords in Windows 11 was disabled in my virtual machine, as described in a superuser post! I needed to disable Windows Hello/PIN to enable password logins with remote desktop (RDP). The superuser page has suggestions about how to use multi-factor-authentication (MFA) instead.

In my case, using remote desktop via Remmina provides better Windows GUI responsiveness (compared to using the QXL driver in virt-manager), with no appreciable penalty in CPU usage.