# Emulating extended page tables for vm



## PacketMan (Mar 15, 2016)

If the moderators think this is more on-topic than off, feel free to move to a more appropriate forum. 

So I picked up a couple old servers that contain Xeon E5430 processors. While they do VT-x, they do not do VT-x with extended page tables.  Some of the programs I want to run (install in Ubuntu server running as a guest OS via Virtualbox) extended page tables I understand.

So my question is: if there a way to have my host OS (FreeBSD 10.2-RELEASE) emulate the extended page tables?  I realize there would be CPU penalty but this is a lab environment. Did some searching on this forum and freshports and googling in general but didn't find anything.

Some guys mentioned maybe I should try vSphere Hypervisor as the vm layer with no host OS, but for the time being I'd like to keep moving forward without removing FreeBSD as host OS.

Thoughts? Is there a port I missed?

I might even see if I can swap the processors with a different flavour that provide the EPT but they would have to be cheap cause I got four of em.


----------



## SirDice (Mar 15, 2016)

PacketMan said:


> So my question is: if there a way to have my host OS (FreeBSD 10.2-RELEASE) emulate the extended page tables?


Probably not as it's a (hardware) feature of the CPU/MMU: 
https://en.wikipedia.org/wiki/Second_Level_Address_Translation#Extended_Page_Tables

It's possible to do but requires changes to the way bhyve handles things. As far as I know it's not as simple as "bolting" some piece of software to it to make it work.


----------



## PacketMan (Mar 15, 2016)

Thanks SirDice.  I'm not using bhyve at the moment, using emulators/virtualbox-ose instead.  I'm guessing that doesn't matter.  Off to the store I go, or maybe I will try blowing away the whole disk and starting from scratch with vSphere Hypervisor, but I expect the same issue.


----------



## SirDice (Mar 15, 2016)

I'm not sure if it requires EPT or if it can run without but you could also give XenServer a shot. Looking at the hardware compatibility list it does seem to include Xeon E54xx CPUs.

http://hcl.vmd.citrix.com/cpus/?cpusupport__version=5&vendor=2


----------

