On Tue, 17 Oct 2017 16:04:48 +0200 Halil Pasic <pa...@linux.vnet.ibm.com> wrote:
> CSS code needs to tell the IO instruction handlers located in how should > the emulated instruction be ended. Currently this is done by returning > generic (POSIX) error codes, and mapping them to outcomes like condition > codes. This makes bugs easy to create and hard to recognise. > > As a preparation for moving a way form (mis)using generic error codes for s/form/from/ > flow control let us introduce a type which tells the instruction > handler function how to end the instruction, in a more straight-forward > and less ambiguous way. > > Signed-off-by: Halil Pasic <pa...@linux.vnet.ibm.com> > --- > include/hw/s390x/css.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h > index 69b374730e..7e0dbd162f 100644 > --- a/include/hw/s390x/css.h > +++ b/include/hw/s390x/css.h > @@ -99,6 +99,22 @@ typedef struct CcwDataStream { > hwaddr cda; > } CcwDataStream; > > +/* > + * IO instructions conclude according this. Currently we have only s/this/to this/ > + * cc codes. Valid values are 0,1,2,3 and the generic semantic for blanks between numbers? > + * IO instructions is described briefly. For more details consult the PoP. > + */ > +typedef enum IOInstEnding { > + /* produced expected result */ > + IOINST_CC_EXPECTED = 0, > + /* status conditions were present or produced alternate result */ > + IOINST_CC_STATUS_PRESENT = 1, > + /* inst. ineffective because busy with previously initiated function */ > + IOINST_CC_BUSY = 2, > + /* inst. ineffective because not operational */ > + IOINST_CC_NOT_OPERATIONAL = 3 > +} IOInstEnding; This looks a bit odd for some I/O instructions (STCRW, TPI, TSCH), but is fine for the others. But as the PoP also defines the meanings as above, it should be fine (and not confusing). > + > typedef struct SubchDev SubchDev; > struct SubchDev { > /* channel-subsystem related things: */