Hi, I have some experience of 3-4 years in managing vm with virtualbox and Vmware.
They performed mostly well, for my purposes, but since vga-passthrough technology seems more mature, I'd like to try it and to do so it seems that Xen or
alternatively KVM are teh best solution for the job. Since I'm not familiar with those solution ( I played a little with KVM and Xen, but not used a lot),
I'd like to ask few questions to the ones who have been successful in configuring vga-passthrough with any of those 2 solutions.

I'd like to set up a vm and assign to it a discrete vga (pci-e) and possibly a soundcard.
My understanding after reading for days about it, is that XEN is the best solution to do that. Now before to buy the wrong/unnecessary hardware , I'd like to have some point cleared possibly by someone who already had to deal with those issues.
My questions are:
1-Can I use integrated vga (intel sandy bridge) for the dom0 (the ubuntu installation) and the discrete one for the domU (in my case, Windows 7 virtualized in the VM)? I read that Xen can assign the primary graphic adapter (defined as the one with which you start the system) and not the second one, which seems a bit weird. So maybe I musnderstood.

2-A big issue (apparently, unless I misunderstood) is that I will have to assign physically a number of cores to the domU which then won't be utilized by the dom0, and that will be permanently (since the domU will start every time I start the dom0 automatically). Isn't possible to make so that the 2 machines share the cpu resources dinamically (menaning allocating up to 100% of the whole cpu resources, based on the contingent needs of one or the other?)

3-Can the same as at question number 2 be applied to the RAM?

4-By setting a DomU with full access to physical hardware, can I still set other vm using Xen but in paravirtualized mode?

Questions about KVM:

A-Did anyone tried vga-passthrough with KVM with Debian/Ubuntu/Mint? Is yes, do you know any guide about it? So far I found one ,but it's based on fedora (which might not be much different from Ubuntu, but still..)


B-Do the preoblems relative to point 1, 2 and 3 apply with KVM too?