On Tue, Oct 06, 2015 at 03:15:57PM +0300, Avi Kivity wrote: > btw, (2) doesn't really add any insecurity. The user could already poke at > the msix tables (as well as perform DMA); they just couldn't get a useful > interrupt out of them.
Poking at msix tables won't cause memory corruption unless msix and bus mastering is enabled. It's true root can enable msix and bus mastering through sysfs - but that's easy to block or detect. Even if you don't buy a security story, it seems less likely to trigger as a result of a userspace bug. -- MST