RE: philosophically about IGD pass-through (was: feature suggestion: DMAR table emulation for Xen)

["James Harper" <james.harper@bendigoit.com.au>]

> > Yes, particularly necessary to get decent 3D performance (e.g.,
Windows
> > Aero). There are tricks to get security and performance (doing a mix
of
> > emulation and passthrough).
> >
> 
> It's good to distinguish 3D acceleration for the *Window Manager* vs.
3D
> acceleration for the *apps*. In Qubes we keep the Window Manager in
> Dom0, so, as long as the graphics driver is not broken, the Window
> Manager gets all the fancy 3D effects, just like on the native.
> 
> The only(?) advantage you gain by using graphics passthorugh is for
the
> apps. But is it really worth it? How many 3D-capable apps business
users
> use today? Google Earth? Anything else? So, in order to support Google
> Earth, is it really worth to introduce potential VM escape attacks?
> 

CAD? Nothing to do with Xen in my case but it's causing one of our
clients grief at the moment as they want to use Windows 7 but one CAD
app only works with XP and 'XP Mode'[1] under Windows 7 just emulates a
craptastic S3 video adapter with no acceleration at all. It looks like
the solution will be 2 PC's for a while...

In that same organisation, most workstations have a requirement to view
the 3D models at reasonable speeds.

I don't see CAD workstations as big users of xen as they are generally
single purpose, but it's probably a mistake to think that the only
business app with 3D visualisation requirements is Google Earth.

James

[1] for anyone who doesn't know, 'XP Mode' is a product that uses
Microsoft VirtualPC to run an instance of XP, licensed as part of the
Windows 7 license. Good for a lot of things, but not CAD.