Increase resolution to 4K in VMware or Virtualbox
Solution 1:
Just give a try to VMware Workstation Technology Preview 2015.
This the "beta" version of Workstation 12. It supports officially highDPI displays.
I just tested it on a linux host with a 4K monitor and it supports this resolution pretty well.
Solution 2:
Both VirtualBox and VMWare should support 4K out of the box as long as the refresh rate is over 60Hz.
For an overview:
- Parallels 10 does a great job at 4K (but we're leaving due to their recent license changes)
- VirtualBox 5.x really stutters at 4K
- VMWare Fusion 8.x is good at 4K (7.x used to be really laggy at 4K)