KVM: x86: PREFETCH and HINT_NOP should have SrcMem flag

KVM: x86: PREFETCH and HINT_NOP should have SrcMem flag

The decode phase of the x86 emulator assumes that every instruction with the
ModRM flag, and which can be used with RIP-relative addressing, has either
SrcMem or DstMem.  This is not the case for several instructions - prefetch,
hint-nop and clflush.

Adding SrcMem|NoAccess for prefetch and hint-nop and SrcMem for clflush.

This fixes CVE-2014-8480.

Fixes: 4f5ee7780a8e229349a8b9366434959f76cbf56c
Cc: stable@vger.kernel.org
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>