How to change DPI on Hyper-V guest Windows Server 2012 operation system

I get a new high DPI laptop recently, its Dell Precision M3800 with QHD+ screen. The laptop is great, extremely fast and QHD+ screen is very sharp and bright, I am very happy with this laptop. But I found than a lot of software are not ready for high DPI yet, so I have issues related to pure support for high DPI with some applications.

One of the issues I have is my Hyper-V virtual machine does not provide me good image quality on guest operation system(Windows server 2012), the text in my VM very small and blurred due to windows trying to scale it and it does not perform job very well. The text I have looks like below and it is almost not possible to use virtual machine for daily work.

The worst thing, Windows does not allow to change DPI on guest OS and shows the following message:

The display settings can’t be changed from a remote session

As aresult all items in “Display” settings are disabled.

But Microsoft still provided option to change DPI using registry settings, which is disabled by default. In order to enable this setting you have to modify the following registry key:

HKEY_CURRENT_USER\Control Panel\Desktop
"Win8DpiScaling"=dword:00000000

The value is 0 by default, so you have to change it to 1 and close/open display settings window. Now all options to change DPI is still disabled, but “Custom sizing options” link is enabled and if you click it.