Xen's paravirtualized mode always requires a guest OS to be modified;
certainly some operating systems would be very hard to make work with
Xen. But you can always fall back to using shadow pagetables or full
hvm (VT/SVM) mode.
Xen manages this stuff with refcounts; it doesn't maintain an rmap for
these pages, so it would have to exhaustively search to do this. But
aside from that, Xen never actively modifies pagetables, so this would
be a new behaviour in the interface.
J
-
