REDHAT-BUG-1277172: High severity Linux KVM vulnerability

It was found that a guest can DoS a host by triggering an infinite loop in microcode. If a guest in 32-bit mode enabled alignment exceptions, puts the exception handler in ring 3, and then triggers an alignment exception with an unaligned stack, then the microcode will enter an infinite loop. Because there's no instruction boundary the core never receives another interrupt (including SMIs). The host kernel panics pretty quickly due to the effects.

A privileged user inside guest could use this flaw to crash the host kernel resulting in DoS.

Upstream KVM patch: ------------------- -> http://permalink.gmane.org/gmane.linux.kernel/2082329

References: ----------- -> http://www.openwall.com/lists/oss-security/2015/11/10/1