KVM: emulator: fix error code for __linearize

The error code for #GP and #SS is zero when the segment is used to
access an operand or an instruction.  It is only non-zero when
a segment register is being loaded; for limit checks this means
cases such as:

* for #GP, when RIP is beyond the limit on a far call (before the first
instruction is executed).  We do not implement this check, but it
would be in em_jmp_far/em_call_far.

* for #SS, if the new stack overflows during an inter-privilege-level
call to a non-conforming code segment.  We do not implement stack
switching at all.

So use an error code of zero.
Reviewed-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/emulate.c

@@ -711,9 +711,9 @@ static int __linearize(struct x86_emulate_ctxt *ctxt,
 	return X86EMUL_CONTINUE;
 bad:
 	if (addr.seg == VCPU_SREG_SS)
-		return emulate_ss(ctxt, sel);
+		return emulate_ss(ctxt, 0);
 	else
-		return emulate_gp(ctxt, sel);
+		return emulate_gp(ctxt, 0);
 }
 
 static int linearize(struct x86_emulate_ctxt *ctxt,