Re: [Xen-devel] [PATCH v12 1/4] x86emul: New return code for unimplemented instruction

[Petre Ovidiu PIRCALABU <ppircalabu@xxxxxxxxxxxxxxx>]

On Thu, 2017-09-21 at 08:53 +0000, Paul Durrant wrote:
> >      }
> > +    case X86EMUL_UNIMPLEMENTED:
> > +        ASSERT_UNREACHABLE();
> > +        /* Fall-through */
>
> Kind of surprised you need the fall-through if you assert the code is
> unreachable... but analysis tools can be a bit temperamental so ok.
>
> >      default:
> >          BUG();
> >      }
> >
> > +    ASSERT(rc != X86EMUL_UNIMPLEMENTED);
> > +
>
> Isn't this assertion redundant given the ASSERT_UNREACHABLE() above?
>
>
> >   Paul

The second ASSERT statement is used to make sure the return value of
hvm_process_io_intercept or hvm_send_ioreq (called from the "case
X86EMUL_UNHANDLEABLE:" branch of the switch statement above) cannot
be X86EMUL_UNIMPLEMENTED.

> hvm_process_io_intercept
> >      if ( rc != X86EMUL_OKAY )
> >          return rc;
> >
> >
//Petre

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