Hiding virtualization details

Some applications will refuse to open under a virtual machine when they can detect it. You can try to hide the fact that the system is running under a virtual machine by modifying your configuration.

Note that these steps are not guaranteed to work for all applications, but this is as far as you'll get without employing shady techniques. Still, this should be more or less good enough for most programs out there.

1. Look for the <os> block, which will look something like:

   <os firmware="efi">
     ...
   </os>

   Append <smbios mode="sysinfo"/> to it:

   <os firmware="efi">
     ...
     <smbios mode="sysinfo"/>
   </os>

2. After the <os> block, append the following:

   <sysinfo type="smbios">
     <bios>
       <entry name="vendor">...</entry>
       <entry name="version">...</entry>
       <entry name="date">...</entry>
       <entry name="release">...</entry>
     </bios>
     <system>
       <entry name="manufacturer">...</entry>
       <entry name="product">...</entry>
       <entry name="version">...</entry>
       <entry name="serial">...</entry>
       <entry name="uuid">...</entry>
       <entry name="sku">...</entry>
       <entry name="family">...</entry>
     </system>
     <baseBoard>
       <entry name="manufacturer">...</entry>
       <entry name="product">...</entry>
       <entry name="version">...</entry>
       <entry name="serial">...</entry>
       <entry name="asset">...</entry>
       <entry name="location">...</entry>
     </baseBoard>
     <chassis>
       <entry name="manufacturer">...</entry>
       <entry name="version">...</entry>
       <entry name="serial">...</entry>
       <entry name="asset">...</entry>
       <entry name="sku">...</entry>
     </chassis>
   </sysinfo>

   You will have to fill in all of the ... parts with actual information, which you should realistically copy from your actual system.

   You can fetch SMBIOS information using dmidecode from the package of the same name.

3. Look for a <uuid> element at the top near <domain>, and replace its contents with the UUID you inserted in <entry name="uuid">:

   <uuid>...</uuid>

   You will also have to change the <name> element to some temporary name, then Apply changes. This is necessary as otherwise virt-manager will complain about a VM with the given name already existing.

   Afterwards, you can go back and delete the old VM (make sure that "Delete associated storage devices" is unchecked) then rename the "new" VM from the temporary name to the original one using the UI. Note that this will lose snapshot information.

4. Look for a <hyperv> block (inside a <features> block), which will look something like:

   <hyperv mode="custom">
     ...
   </hyperv>

   Replace it with:

   <hyperv mode="passthrough"/>
   <kvm>
     <hidden state="on"/>
   </kvm>

5. Look for the <cpu mode="host-passthrough"> block again. In it, append <feature policy="disable" name="hypervisor"/>, like:

   <cpu mode="host-passthrough" ...>
     ...
     <feature policy="disable" name="hypervisor"/>
   </cpu>

6. Look for the <clock offset="localtime"> block, which will look like:

   <clock offset="localtime">
     ...
   </clock>

   Replace it with;

   <clock offset="localtime">
     <timer name="rtc" present="no" tickpolicy="catchup"/>
     <timer name="pit" tickpolicy="discard"/>
     <timer name="hpet" present="no"/>
     <timer name="kvmclock" present="no"/>
     <timer name="hypervclock" present="yes"/>
     <timer name="tsc" present="yes" mode="native"/>
   </clock>

7. Lastly, inside Windows, you will have to modify the SystemBiosVersion key in HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System in the registry and replace BOCHS - 1 and EDK II - 10000 with proper strings. You can take these strings from an existing baremetal Windows installation, if you have one; at worst, you can take them from the internet.

   Note that the SystemBiosVersion key resets everytime you boot Windows, so you will likely want to automate setting it on login. How to do this is left as an exercise to the reader.