KVM: x86: Non-canonical access using SS should cause #SS

When SS is used using a non-canonical address, an #SS exception is generated on
real hardware.  KVM emulator causes a #GP instead. Fix it to behave as real x86
CPU.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -635,7 +635,7 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
 	switch (mode) {
 	case X86EMUL_MODE_PROT64:
 		if (is_noncanonical_address(la))
-			return emulate_gp(ctxt, 0);
+			goto bad;
 
 		*max_size = min_t(u64, ~0u, (1ull << 48) - la);
 		if (size > *max_size)