In other words, the triple-fault[1] is broken? This looks like a bad hardware bug, a <i>really bad</i> one. AFAIK on real hardware it does what it should, i.e. causes the CPU to reset. The fact that OSs in the past have relied on triple-faulting to cause a reset[2] makes this all the more unusual. Then again, I suppose no one has really tried to run MS-DOS and related software in Xen...<p><i>the vulnerability can be avoided altogether if
the guest kernel is controlled by the host rather than guest
administrator</i><p>That sort of defeats the point of using a VM, doesn&#x27;t it?<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Triple_fault" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Triple_fault</a><p>[2] <a href="http:&#x2F;&#x2F;www.rcollins.org&#x2F;Productivity&#x2F;TripleFault.html" rel="nofollow">http:&#x2F;&#x2F;www.rcollins.org&#x2F;Productivity&#x2F;TripleFault.html</a>