kernel: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1

A flaw was found in the Kernel-based Virtual Machine KVM nSVM module of the Linux kernel. This vulnerability occurs when an unhandled VMMCALL is not properly intercepted by the Level 1 L1 hypervisor. A malicious Level 2 L2 guest operating system could exploit this by making specific hypercalls,...