kvm: vmx: handle invvpid vm exit gracefully

kvm: vmx: handle invvpid vm exit gracefully

On systems with invvpid instruction support (corresponding bit in
IA32_VMX_EPT_VPID_CAP MSR is set) guest invocation of invvpid
causes vm exit, which is currently not handled and results in
propagation of unknown exit to userspace.

Fix this by installing an invvpid vm exit handler.

This is CVE-2014-3646.

Cc: [email protected]
Signed-off-by: Petr Matousek <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>