Create R2->R3 migration tool for windows tools

[omeg]

Windows HVMs with R2 tools won't boot in R3 normally because Xen disk drivers won't load. Check safe mode. Integrating migration with the R3 tools installer would be ideal but MSI service doesn't run in safe mode normally - investigate.

[omeg]

R2 HVM boots in safe mode in R3 (can be accessed through startup recovery, not selecting any options like system restore, choosing advanced options once it fails, command prompt: bcdedit /set safeboot minimal).
Once it's booted (in safe mode) some gplpv drivers can be disabled: uninstall xenvif and xenvbd from the device manager, select "remove files", make sure the files are really gone from c:\windows\system32\drivers so they don't reactivate on next boot, delete registry keys from HKLM\System\CurrentControlSet\Services).
After reboot Windows should be using emulated network and disk devices. At this point safe boot can be disabled (bcdedit /deletevalue safeboot). However, the xenpci driver cannot be disabled/removed - OS fails to boot with BSOD 7b (inaccessible boot device) in that case. That's really strange since only emulated devices are active at this point...
Installing the new pvdrivers fails if the old xenpci driver is active.

[omeg]

R2 HVM boots in safe mode in R3 (can be accessed through startup recovery, not selecting any options like system restore, choosing advanced options once it fails, command prompt: bcdedit /set safeboot minimal).
Once it's booted (in safe mode) some gplpv drivers can be disabled: uninstall xenvif and xenvbd from the device manager, select "remove files", make sure the files are really gone from c:\windows\system32\drivers so they don't reactivate on next boot, delete registry keys from HKLM\System\CurrentControlSet\Services).
After reboot Windows should be using emulated network and disk devices. At this point safe boot can be disabled (bcdedit /deletevalue safeboot). However, the xenpci driver cannot be disabled/removed - OS fails to boot with BSOD 7b (inaccessible boot device) in that case. That's really strange since only emulated devices are active at this point...
Installing the new pvdrivers fails if the old xenpci driver is active.

[omeg]

Old xenpci is added as an UpperFilter to the following device classes:
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E97B-E325-11CE-BFC1-08002BE10318}

If those filter entries are removed it's possible to completely remove it and install R3 tools.

[omeg]

Old xenpci is added as an UpperFilter to the following device classes:
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E97B-E325-11CE-BFC1-08002BE10318}

If those filter entries are removed it's possible to completely remove it and install R3 tools.

[omeg]

https://www.qubes-os.org/doc/UninstallingWindowsTools2/

[omeg]

https://www.qubes-os.org/doc/UninstallingWindowsTools2/