logo of the KVM [archive] virtualizer

General[edit]

What is KVM?[edit]

For an openly developed, free and open-source software (FOSS), GPL licensed hypervisor that can run Whonix,^[1] it is recommended to use Kernel Virtual Machine (KVM) ^[archive] that comes with the GNU/Linux OS. KVM combined with the VirtualMachineManager ^[archive] front-end should provide a familiar, intuitive and easy-to-use GUI. KVM uses libvirt ^[archive].

For a detailed view on KVM's security merits read the audit report ^[archive] issued by an independent security auditing firm.

Why Use KVM Over VirtualBox?[edit]

The VirtualBox developer team have recently taken the decision to switch out the BIOS in their hypervisor. However, it now comes with one that requires compilation by a toolchain that does not meet the definition of Free Software as per the guidelines of the Free Software Foundation. This move is considered problematic for free and open source software projects like Debian, on which Whonix ™ is based.

The issues of the Open Watcom License are explained in this thread ^[archive] on the Debian Mailinglist. More references can be found here. In summary, there are issues surrounding the contradictory language of the license, the assertion of patents against software that rely upon it, and the placing of certain restrictions on software uses. For these reasons, those who care about running FOSS and appreciate its ethical views are recommended to avoid running VirtualBox; also see avoid non-freedom software.

Besides this licensing issue, a more tangible reason to avoid VirtualBox is the security practices of Oracle who produce the software. Events and news in recent years (like the Snowden leaks) demonstrate there is an urgent need for increased transparency and verifiable trust in the digital world. Oracle is infamous for their lack of transparency in disclosing the details of security bugs, as well as discouraging full and public disclosure by third parties. Security through obscurity ^[archive] is the flawed modus operandi ^[archive] at Oracle. ^[2]

Not going public with the details of vulnerabilities only leads to laziness and complacency on behalf of the company that fields the affected products. One example is this historical 0day vulnerability ^[archive] reported privately to Oracle in 2008 by an independent security researcher. Over four years later, the vulnerability remained unfixed ^[archive], exhibiting Oracle has a history of failing to provide timely patches to customers so they can protect themselves.

On the VirtualBox bugtracker, ticket VirtualBox 5.2.18 is vulnerable to spectre/meltdown despite microcode being installed indicates non-responsiveness and non-progress by upstream. Users must patiently wait for VirtualBox developers to fix this bug.^[3]

VirtualBox also contains significant functionality that is only available as a proprietary extension, such as USB / PCI passthrough and RDP connectivity. Based on Oracle's unfriendly track record with the FOSS community in the past -- examples include OpenSolaris and OpenOffice -- it would be unsurprising if users were charged for these restricted features in the future, or if the project was abandoned due to insufficient monetization.

First-time User?[edit]

KVM Setup Instructions[edit]

Before Installing[edit]

Refer to the Computer Security Education chapters here and apply relevant steps.

Install KVM[edit]

Debian[edit]

su -

sudo adduser user sudo

reboot

sudo apt update

sudo apt install --no-install-recommends qemu-kvm libvirt-daemon-system libvirt-clients virt-manager gir1.2-spiceclientgtk-3.0 dnsmasq qemu-utils

sudo apt install --no-install-recommends qemu-system-ppc libvirt-daemon-system libvirt-clients virt-manager gir1.2-spiceclientgtk-3.0 dnsmasq qemu-utils

Ubuntu[edit]

sudo apt install qemu-kvm libvirt-clients libvirt-daemon-system bridge-utils libguestfs-tools genisoimage virtinst libosinfo-bin virt-manager

sudo adduser $USER libvirt

sudo adduser $USER libvirt-qemu

Arch Linux[edit]

sudo pacman -Syu qemu libvirt virt-manager qemu-arch-extra

Other Distributions[edit]

error: Failed to define domain from Whonix-Gateway_kvm-8.6.2.8.xml
error: internal error Unknown controller type 'pci

Whonix-Gateway_kvm-8.6.2.8.xml:24: element pm: Relax-NG validity error : Element domain has extra content: pm
Whonix-Gateway_kvm-8.6.2.8.xml fails to validate

Relax-NG validity error : Extra element devices in interleave
Whonix-Gateway_kvm-8.6.2.8.xml:24: element devices: Relax-NG validity error : Element domain failed to validate content
Whonix-Gateway_kvm-8.6.2.8.xml fails to validate

Readers are welcome to add detailed instructions for other distributions here!

Notice[edit]

Arch/Ubuntu Users[edit]

• As of March 2019, it has been reported that the blkio throttling feature appears to be missing/unsupported on the latest Arch version. This causes a failure during VM start up.^[5] The VM also fails to start up on Ubuntu 20.04 with a "blkio" error. The current work around is to remove the feature for now.

sudo virsh edit Whonix-Gateway

 <blkiotune>
    <weight>250</weight>
</blkiotune>

• The pvspinlock feature is reported to not be supported and the issue was resolved when edited out of the VM config.

Addgroup[edit]

In order to be able to manage virtual machines as a regular (non-root) user, that user must be added to the libvirt and the kvm groups. The following command will work in Debian and assumes the simple scenario whereby KVM will be utilized with the current logged in user. For older Ubuntu versions, note that the group names vary and libvirt may be called libvirtd instead. For Ubuntu 20.04, libvirt works.

sudo addgroup "$(whoami)" libvirt

sudo addgroup "$(whoami)" kvm

^[6]

Other Distributions[edit]

If another distribution is in use, then first refer to the distribution manual. For example, a necessary reference for Arch users is the Arch Linux libvirt wiki page ^[archive].

Reboot[edit]

Note: A reboot is required after:

• KVM is installed.
• Users are added to groups.

sudo reboot

Network Start[edit]

Ensure KVM's / QEMU's default networking is enabled and has started. ^{[7] [8]}

sudo virsh -c qemu:///system net-autostart default

sudo virsh -c qemu:///system net-start default

Build from Scratch[edit]

Advanced users are encouraged to build Whonix ™ images for high security assurance.

Download and Extract[edit]

Introduction[edit]

It is strongly recommended to read and apply the steps outlined in this section. By applying a known and tested configuration, this will provide better convenience and security.

Be sure to use the qcow2 images that are provided by the Whonix ™ project instead of rolling your own ^[9] because they contain important performance optimizations. ^[10] The only exception is if images were created from source. ^[11]

If problems are encountered with free disk space, using a file system that supports sparse files is recommended. Also refer to the following forum discussion ^[archive].

If Whonix ™ libvirt images already exist, then consider a Cleanup first.

For simplicity the Whonix ™ images should be downloaded and stored in the home folder (/home/<your user name>) so the following commands can be copied/pasted without changes.

Download Whonix ™[edit]

FREE Download

Version: 16.0.3.1

Type	Connection	Link	Download Security without Verification	Download Security with Verification
		Download (TLS)	Medium	High [12]
		Download (Onion)	Medium	High
		OpenPGP Signature (TLS) sha512 sha512 OpenPGP sha512 Signify	-	-
		OpenPGP Signature (Onion) sha512 sha512 OpenPGP sha512 Signify	-	-
		Verify images using this Signing Key

Verify the Whonix ™ Images[edit]

• Whonix ™ KVM Signing Key
• Verify the Whonix ™ KVM images

Decompress[edit]

1. Ensure the tarball is in the user home folder before applying these steps.

2. Do not use unxz! Extract the images using gnu tar.

3. Use gnu tar to decompress the archive.

tar -xvf Whonix*.libvirt.xz

License Agreement[edit]

more WHONIX_BINARY_LICENSE_AGREEMENT

touch WHONIX_BINARY_LICENSE_AGREEMENT_accepted

touch WHONIX_BINARY_LICENSE_AGREEMENT_denied

Optional: XML Modification[edit]

This section describes XML modifications before importing a virtual machine. For virtual machines that were already imported, see: Editing an Imported Machine's XML Configuration.

Modifying a machine's XML file provides more fine-grained control over its settings than what is exposed through the virt-manager GUI. Unless you are knowledgeable about this process, editing configuration defaults is neither recommended nor necessary.

Open file Whonix-Gateway*.xml in a text editor of your choice as a regular, non-root user.

mousepad Whonix-Gateway*.xml

nano Whonix-Gateway*.xml

Open file Whonix-Workstation*.xml in a text editor of your choice as a regular, non-root user.

mousepad Whonix-Workstation*.xml

nano Whonix-Workstation*.xml

It is possible to edit the XML files later on if this is necessary, see: Editing an Imported Machine's XML Configuration.

Importing Whonix ™ VM Templates[edit]

The first step after extracting the archive is to import the supplied XML files. They serve as a description for libvirt ^[archive] and define the properties of the Whonix ™ VMs and the networking they should have.

sudo virsh -c qemu:///system net-define Whonix_external*.xml

sudo virsh -c qemu:///system net-define Whonix_internal*.xml

sudo virsh -c qemu:///system net-autostart Whonix-External

sudo virsh -c qemu:///system net-start Whonix-External

sudo virsh -c qemu:///system net-autostart Whonix-Internal

sudo virsh -c qemu:///system net-start Whonix-Internal

sudo virsh -c qemu:///system define Whonix-Gateway*.xml

sudo virsh -c qemu:///system define Whonix-Workstation*.xml

Moving Whonix ™ Image Files[edit]

The XML files are configured to point to the default storage location of /var/lib/libvirt/images. The following steps move the images there so the machines can boot.

Note: Changing the default location may cause conflicts with SELinux, which will prevent the machines from booting.

It is recommended to move the image files instead of copying them.

sudo mv Whonix-Gateway*.qcow2 /var/lib/libvirt/images/Whonix-Gateway.qcow2

sudo mv Whonix-Workstation*.qcow2 /var/lib/libvirt/images/Whonix-Workstation.qcow2

Copying Whonix ™ Image Files[edit]

Whonix ™ disk images are sparse files, meaning they expand when filled rather than allocating their entire size (100GB outright). Sparse files require special commands when they are copied to ensure they do not lose this property, otherwise they will occupy all of the actual space. Higher privileges (sudo) are required because the copying is to a privileged location in the system.

sudo cp --sparse=always Whonix-Gateway*.qcow2 /var/lib/libvirt/images/Whonix-Gateway.qcow2

sudo cp --sparse=always Whonix-Workstation*.qcow2 /var/lib/libvirt/images/Whonix-Workstation.qcow2

Manipulating QCOW2 Images[edit]

Use qemu-img to interact with KVM disk images. This software can resize virtual disks, convert virtual disks to other formats, and more. It is not necessary nor recommended to change the official images, so proceed cautiously and only if the procedure is understood.

For more commands, refer to the qemu-img manual ^[archive].

Encrypted Containers[edit]

It is possible to run image files from encrypted containers. sVirt protections are confirmed to be in effect for image files at alternative locations.

Change the permissions on the container mount point directory so virtual machine manager can access the image. In Zulucrypt, containers are mounted under /run/media/private/user: ^[13]

sudo chmod og+xr /run/media/private/user/$container_name

Cleanup[edit]

After importing Whonix ™, it is advised to delete the archives (.libvirt.xz files) and the temporarily extracted folders, or to move them into a custom location. This is useful to avoid conflicts and confusion if a new version of Whonix ™ is later downloaded.

To delete the archives and temporary folders, run.

rm Whonix*
rm -r WHONIX*

Start[edit]

If Virtual Machine Manager is familiar, there is nothing special about starting Whonix ™ VMs compared to starting other VMs. First start Whonix-Gateway ™, then start Whonix-Workstation ™.

Graphical User Interface (GUI)[edit]

Start Virtual Machine Manager.

Start Menu → Applications → System → Virtual Machine Manager

Start Whonix-Gateway ™.

click on Whonix-Gateway → click open → click the play symbol

Repeat the steps for Whonix-Workstation ™.

Command Line Interface (CLI)[edit]

On the host.

To start Whonix-Gateway ™, run.

sudo virsh start Whonix-Gateway

To start Whonix-Workstation ™, run.

sudo virsh start Whonix-Workstation

To interact with the Whonix-Workstation ™ via serial console ^[archive], run.

sudo virsh console Whonix-Workstation

To disable startup of the included Desktop Environment regardless of how much RAM is assigned to the VM, configure RAM Adjusted Desktop Starter package settings.

Adjust Display Resolution[edit]

Whisker Menu → display → select resolution ^[14]

Save and then take a snapshot.

Alternatively,

GUI Console → View → Scale Display → Check: Always + Auto resize VM with window. Every new session, a reboot is needed while the VM's GUI console is open and maximized to activate display resize.

After Installing[edit]

Read and apply the Post Installation Security Advice.

Uninstall[edit]

sudo virsh -c qemu:///system destroy Whonix-Gateway

sudo virsh -c qemu:///system destroy Whonix-Workstation

sudo virsh -c qemu:///system undefine Whonix-Gateway

sudo virsh -c qemu:///system undefine Whonix-Workstation

sudo virsh -c qemu:///system net-destroy Whonix-External

sudo virsh -c qemu:///system net-destroy Whonix-Internal

sudo virsh -c qemu:///system net-undefine Whonix-External

sudo virsh -c qemu:///system net-undefine Whonix-Internal

sudo rm /var/lib/libvirt/images/Whonix-Gateway.qcow2

sudo rm /var/lib/libvirt/images/Whonix-Workstation.qcow2

KVM Upgrade Instructions[edit]

It is strongly recommended to uninstall older Whonix ™ versions and always run the stable release. Note that Whonix ™ supports in-place APT upgrades too.

1. Move your data out of the VM via shared folders.
2. Perform the Cleanup steps.
3. Install the new images.

Optional[edit]

Multiple Whonix-Gateway ™[edit]

See: Multiple Whonix-Gateway ™.

Testing Upcoming Versions[edit]

Download the test images from the latest folder listed here ^[archive]. Apply the Multiple Whonix-Gateway KVM steps for running Whonix ™ versions side by side with some differences:

1. Rename the test Whonix ™ images to something unique, preferably by appending the version number to the name.
2. Edit the XML templates and change the VM names.
3. Import the images by following the Importing Whonix installation steps. Keep in mind the full name of the new images must be used and do not import the Network templates.

Convert Libvirt Templates to QEMU Commands[edit]

1. First export the VM template as a file:

   sudo virsh dumpxml Whonix-Gateway > Whonix-Gateway.xml

   sudo virsh dumpxml Whonix-Gateway > Whonix-Gateway.xml

2. Convert it to the QEMU command:

   sudo virsh domxml-to-native qemu-argv Whonix-Gateway.xml > Whonix-Gateway.args

   sudo virsh domxml-to-native qemu-argv Whonix-Gateway.xml > Whonix-Gateway.args

3. Repeat for the Whonix-Workstation. Replace Whonix-Gateway with Whonix-Workstation in above commands.

Magic SysRq Keys[edit]

Magic SysRq keys are useful when the guest is unresponsive, especially in cases where VMs are running headless and a GUI console is not available for forcing them to shut off on the host.^[16]

Example command to shut down Whonix ™ Workstation from a host console. The O at the end of KEY_O can be substituted with any other supported letter ^[archive] listed in the kernel documentation. See also SysRq.

sudo virsh send-key Whonix-Workstation KEY_LEFTALT KEY_SYSRQ KEY_O

DHCP[edit]

Libvirt provides built-in DHCP functionality via a custom install of the minimalist Dnsmasq DNS/DHCP daemon. ^[17] This is useful when running multiple Workstations concurrently that are attached to the same Gateway, and for custom Workstations running Android x86.

For privacy and traffic leak purposes Dnsmasq does not resolve DNS as implemented in Libvirt. ^{[18] [19]} DNS is not explicitly enabled for guests unless it is added to a network’s configuration. ^{[20] [21]} Even when DNS is enabled, the way Libvirt uses it does not increase the host's attack surface (by using raw sockets for example) nor does DHCP because it is bound to a specific NIC in this case. ^[22] Trying to edit the Dnsmasq configuration files directly will fail as settings are rewritten and are enforced through Libvirt by design. ^[23]

sudo nano /etc/network/interfaces.d/30_non-qubes-whonix

auto eth0
iface eth0 inet static

auto eth0
iface eth0 inet dhcp

sudo virsh net-edit Whonix-Internal

<ip address='10.152.152.0' netmask='255.255.192.0'>
    <dhcp>
      <range start='10.152.128.1' end='10.152.191.254'/>
    </dhcp>
</ip>

sudo virsh net-destroy Whonix-Internal

sudo virsh -c qemu:///system net-start Whonix-Internal

Snapshot Migration[edit]

If the VM has snapshots that you wish to preserve, the snapshot xml-files of the source VM should be dumped with the following commands. ^[24]

sudo virsh snapshot-list --name $dom

sudo virsh snapshot-dumpxml $dom $name > file.xml

sudo virsh snapshot-create --redefine $dom file.xml

sudo virsh snapshot-current --name $dom

sudo virsh snapshot-current $dom $name

Nested KVM Virtualization[edit]

It is possible to create nested KVM VMs on KVM hosts. As root...

Check the current setting on the host. If the result is [Y], then it is okay.

sudo cat /sys/module/kvm_intel/parameters/nested

For AMD systems use kvm_amd instead.

sudo cat /sys/module/kvm_amd/parameters/nested

If the result is [N], run the following command and reboot the system.

For Intel systems:

echo 'options kvm_intel nested=1' | sudo tee -a /etc/modprobe.d/qemu-system-x86.conf

For AMD systems:

echo 'options kvm_amd nested=1' | sudo tee -a /etc/modprobe.d/qemu-system-x86.conf

Host CPU instructions that include the svm and vmx extensions are passed through to the Workstation by default.

Compressing Disk Images[edit]

Some users find it easier to move the sparse image files when they are compressed in a tarball.

To re-compress files, run.

tar -Sczvf whonix.tar.gz <multiple file names separated by spaces>

Adding vCPUs[edit]

The pinning parameter cpuset='1' must be removed in the vcpu tag in the XML settings to allow adding more cores to a VM, otherwise performance issues and lockups will occur. CPU pinning is done to safeguard processes in other VMs that run cryptographic operations from side-channel attacks in case of a vulnerability in a cryptographic library.

To add more vcpus, increase the number in between the opening and closing vcpu tags. Alternatively, use the hardware 'Details' pane in virtual Machine Manager.

If preserving cpu pinning while increasing core count is desired, pin the vcpus to different numbered ones compared to other sensitive VMs. Map them in a 1:1 ratio to avoid over committing cores (which leads to performance problems).

3D Graphics Acceleration[edit]

Not yet functional as of Debian buster but this has been fixed upstream. Future enhancements for performance and security are planned. Will revisit in Bullseye.

Shared Folders[edit]

Follow these steps to move data between the guest and host. It is recommended to create/assign a unique directory per snapshot to keep shared content belonging to different security domains separate.

mkdir /home/user/shared

chmod 777 /home/user/shared

Mandatory Access Control[edit]

Note: If your system is configured to use a Mandatory Access Control framework then it might be necessary to configure exceptions to allow the confined guests to communicate with the shared folder on the host.

Tests with Apparmor have shown it operates transparently with shared folders, without the need for a manual exception configuration.

On the host, chmod must be applied to the shared folder's contents to access the files.

Replace user name user with your actual user name.

sudo chmod 777 -R /home/user/shared

If SELinux is disabled then everything should be functional. If SELinux is enabled, it is necessary to add a policy for files under the shared folder on the host. SELinux will not allow this folder to be shared until it is labeled svirt_image_t. To achieve this add the following policy on the host using semanage. Note that these steps must be re-applied every time something is transferred. ^{[26] [27]}

sudo semanage fcontext -a -t svirt_image_t "/home/user/shared(/.*)?"

restorecon -vR /home/user/shared

Setting permissions on the user folder itself as follows may be necessary for the guest to start up without a permission error.

sudo chmod 701 /home/user

If you are using the command line instead of virt-manager to edit the vm's device settings, add this next section to the xml.

<filesystem type='mount' accessmode='mapped'>
    <source dir='/home/user/shared'/>
    <target dir='shared'/>
</filesystem>

USB Passthrough[edit]

Libvirt supports passing through a computer's integrated webcam or any other USB devices. ^{[28] [29]} Debian contributors have disabled USB auto-redirection by default to prevent the accidental passthrough of trusted USB devices to untrusted guests, ^{[30] [31]} so they must be reverted temporarily. Once finished, change them back to safe defaults by going through the steps in reverse order.

Limitations: These steps apply to USB storage devices only. Portable devices such as phones and tablets are problematic and may not be successfully auto-redirected.

The USB drive will only be isolated so long as the Whonix-Workstation ™ is running. Do not close the VM GUI window or the device will be reassigned to the host. The VM window must be in focus (either mouse grabbed or in fullscreen mode just to be safe) when initially plugging in the device. The VM window can be minimized after it is detected in the guest. It is unnecessary to wait for the VM to completely boot.

sudo nano /usr/share/glib-2.0/schemas/10_virt-manager.gschema.override

[org.virt-manager.virt-manager.console]
auto-redirect=false

[org.virt-manager.virt-manager.console]

sudo glib-compile-schemas /usr/share/glib-2.0/schemas/

Editing an Imported Machine's XML Configuration[edit]

Eventually configure your favorite editor to make changes. Set visual as your favorite editor -- the relevant software must be installed, such as kwrite, leafpad, kate, vi, nano, vim and so on.

export VISUAL=kwrite

Edit.

sudo virsh -c qemu:///system edit Whonix-Gateway

In more recent versions of virt-manager, there is a second way available:

Virtual Machine Manager -> Edit -> Preferences -> General -> Enable XML Editing

Under the Details view for a VM, a new XML tab in the GUI is visible, allowing editing and saving directly from the VM viewer.

Enable Microphone Input[edit]

Microphone input to guests is a nice feature for VoIP, but it is dangerous to have on by default. It is good practice to disable the microphone on your host system through sound settings when it is not in active use.

The shipped configuration only includes a speaker by default (without a microphone) to prevent malware in the VM from eavesdropping on the user. To enable microphone input for select guests, edit the configuration and change <codec type='output'/> -> <codec type='micro'/>.

Creating Multiple Internal Networks[edit]

Open the Whonix ™ network XML file and change the name attribute to something different than the internal network that is currently running, for example 'Whonix-Internal2', 'Whonix-Internal3' and so on. The default network name in use is 'Whonix-Internal'.

Alternative Configurations[edit]

Libvirt can support a variety of containment mechanisms. Currently supported mechanisms include KVM on the x86_64 platform and QEMU, but more configurations might be added at a later date. If hardware virtualization extensions are available, always use the KVM one.

To use another configuration, import its XML file with virsh.

How to Leave KVM when no X is Running[edit]

In the hypothetical situation whereby a user is "trapped" in a virtual console inside a VM without graphical desktop environment (X Window System) ("sudo service lightdm stop"), it is still possible to switch back to the host.

In other words, should the graphical desktop environment crash or be terminated, the user may be "trapped" inside a black VM window. It is possible to exit this.

The emulated tablet device handles this by not allowing the mouse to be captured by the guest, however this is still possible:

Press Ctrl_L & Alt_L

Setting up gdb to work with qemu-kvm via libvirt[edit]

In order to debug a Linux kernel that is running as a KVM guest, the -s parameter must be specified for the command line of qemu-kvm. Unfortunately there is no (easy) way to do this when libvirt and virt-manager are used to manage your virtual machines (instead of using KVM directly). In this case it is necessary to change the XML configuration of the virtual machine so that the -s parameter is passed on to qemu-kvm.

sudo virsh edit $guestvm

<domain type='kvm'>

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>

<qemu:commandline>
<qemu:arg value='-s'/>
</qemu:commandline>

target remote localhost:1234

Unsafe Features[edit]

The features below have serious security implications and should not be used. This applies to all hypervisors in general.

LVM Storage[edit]

QCOW2 virtual disk images are the recommended and default storage format for KVM. LVM or any other storage mechanism must be avoided for security and privacy. LVM misconfiguration has serious security consequences and exposes the host filesystem to the processes running on the guest. ^[34]

In the event a virtual disk is no longer used -- where the low-level view of the storage can be controlled -- data created by VMs can easily be recovered and exfiltrated by malicious forensics tools run in a VM at a later time. This is extremely dangerous and can expose all kinds of information originally created in a VM of higher trust level. This leads to deanonymization, past session linking and theft of sensitive information and keys. ^{[35] [36]} This setting is disabled in cloud tenancy environments.

HugePages[edit]

THP/Hugepages aid rowhammer attacks ^[37] and memory de-duplication attacks (see KSM below) and therefore must be disabled for the guest and on the host. Research suggests that Debian hosts do not enable this feature and it is also disabled in cloud tenancy environments.

Memory Ballooning[edit]

Memory ballooning can potentially be abused by malicious guests to mount rowhammer attacks on the host. ^[38]

Clipboard Sharing[edit]

SPICE allows accelerated graphics and clipboard sharing. The clipboard is disabled by default for security reasons:

• To prevent the accidental copying of a link to a website that was visited anonymously to the non-anonymous host browser (or vice versa).
• To stop malware in Whonix ™ Workstation from pilfering sensitive info from the clipboard.

If you still want to enable it, edit the VM config file and then change <clipboard copypaste='no'/> to 'yes', then save and restart.

KSM[edit]

KSM is a memory de-deuplication feature that conserves memory by combining identical pages across VM RAM, but it is not enabled by default. Enabling this feature is dangerous because it allows cross-VM snooping by a malicious process. ^[39] It is capable of inferring what programs/pages are being visited outside the VM. ^[40] This feature is disabled in cloud tenancy environments and can also allow attackers to modify/steal APT keys and source lists of the host. ^{[41] [42]}

File-system Dedupe[edit]

Similar to KSM memory dedupe, filesystem dedupe introduces data leaks that violate hypervisor boundaries. The presence of certain files can be confirmed. These may develop into more advanced attacks on security in the future just like KSM related attacks have. ZFS and Btrfs have dedupe features but they are not enabled by default and should be avoided for high security environments.^[43]

Device Passthrough[edit]

Both USB and PCI device passthrough permit advanced attackers to flash the firmware of those devices and infect the host or other VMs. ^[44]

XML Settings[edit]

For more information on settings, please refer to the Libvirt manual ^[archive].

Troubleshooting[edit]

Reboot?[edit]

• Did you reboot after installing KVM?
• Did you reboot after adding users to groups?

Please add this information if making a support request.

Unable to connect to libvirt[edit]

If the following error appears.

Unable to connect to libvirt.

Verify that the 'libvirtd' daemon is running.

Libvirt URI is: qemu:///system

Make sure you added groups and rebooted.

Unable to open a connection to the libvirt management daemon[edit]

If the following error appears.

Unable to open a connection to the libvirt management daemon.

Libvirt URI is: qemu:///system

Verify that:
- The 'libvirtd' daemon has been started

Check the KVM installation.

sudo service qemu-system-x86 restart ; echo $? ; sudo service libvirt-bin restart ; echo $? ; sudo service libvirt-guests restart ; echo $?

The output should show.

0
[ ok ] Restarting libvirt management daemon: /usr/sbin/libvirtd.
0

Running guests on default URI: no running guests.
0

In this case, it could be a permissions problem.

hda-duplex not supported in this QEMU binary[edit]

If this error appears you might be a member of the libvirt group, but lack membership of the kvm group.

In this case, it helps to change.

    <sound model='ich6'>

To.

    <sound model='ac97'>

process exited while connecting to monitor: ioctl(KVM_CREATE_VM) failed[edit]

If the following error appears.

Error starting domain: internal error: process exited while connecting to monitor: ioctl(KVM_CREATE_VM) failed: 16 Device or resource busy
failed to initialize KVM: Device or resource busy

Then it is not possible other non-KVM VMs (such as VirtualBox VMs) might already be running, since two concurrent hypervisor instances is not supported by KVM / VirtualBox.

Permissions[edit]

ls -la /var/run/libvirt/libvirt-sock

invalid argument: could not find capabilities for domaintype=kvm[edit]

Add Version Numbers to Support Request[edit]

If problems are experienced, be sure to note what versions of libvirt-bin, qemu-kvm and virt-manager are in use as part of the support request. If you are using Debian, the following command will determine the software versions.

dpkg-query --show --showformat='${Package} ${Version} \n' libvirt-bin qemu-kvm virt-manager

Check Groups[edit]

Check the output of following command.

whoami

The output of the previous command is expected to be something like user or your linux user account name. Should not be root.

groups

The output of the previous command is expected to include the groups libvirt and kvm. ^[45] If that is not the case, make sure you added groups and rebooted.

Support[edit]

Whonix ™ KVM maintainer availability is mostly limited to User Help Forum.

Questions on telegram, matrix, IRC, reddit, incomplete list will most likely not get attention by Whonix ™ KVM maintainer.

See also Support.

User Help Forum[edit]

Whonix ™ KVM User Help Forum ^[archive]

Alternative Guides[edit]

For alternative installation guides contributed by community members, see: Installation Screenshots.

Development[edit]

• KVM Development
• KVM Whonix ™ Bug Tracker ^[archive]
• whonix-libvirt github ^[archive]

Footnotes[edit]

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