diff mbox

[v3,7/7] s390x: refactor error handling for MSCH handler

Message ID 20171017140453.51099-8-pasic@linux.vnet.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Halil Pasic Oct. 17, 2017, 2:04 p.m. UTC
Simplify the error handling of the MSCH.  Let the code detecting the
condition tell (in a less ambiguous way) how it's to be handled. No
changes in behavior.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
---
 hw/s390x/css.c         | 18 +++++-------------
 include/hw/s390x/css.h |  2 +-
 target/s390x/ioinst.c  | 23 ++++-------------------
 3 files changed, 10 insertions(+), 33 deletions(-)

Comments

Cornelia Huck Oct. 17, 2017, 3:11 p.m. UTC | #1
On Tue, 17 Oct 2017 16:04:53 +0200
Halil Pasic <pasic@linux.vnet.ibm.com> wrote:

> Simplify the error handling of the MSCH.  Let the code detecting the
> condition tell (in a less ambiguous way) how it's to be handled. No
> changes in behavior.
> 
> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> ---
>  hw/s390x/css.c         | 18 +++++-------------
>  include/hw/s390x/css.h |  2 +-
>  target/s390x/ioinst.c  | 23 ++++-------------------
>  3 files changed, 10 insertions(+), 33 deletions(-)

Looks sane (quoting the whole mail for the benefit of the qemu-s390x list).

> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index b9e0329825..30fc236946 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -1347,28 +1347,24 @@ static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
>      }
>  }
>  
> -int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
>  {
>      SCSW *s = &sch->curr_status.scsw;
>      PMCW *p = &sch->curr_status.pmcw;
>      uint16_t oldflags;
> -    int ret;
>      SCHIB schib;
>  
>      if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
> -        ret = 0;
> -        goto out;
> +        return IOINST_CC_EXPECTED;
>      }
>  
>      if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
> -        ret = -EINPROGRESS;
> -        goto out;
> +        return IOINST_CC_STATUS_PRESENT;
>      }
>  
>      if (s->ctrl &
>          (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
> -        ret = -EBUSY;
> -        goto out;
> +        return IOINST_CC_STATUS_PRESENT;
>      }
>  
>      copy_schib_from_guest(&schib, orig_schib);
> @@ -1395,11 +1391,7 @@ int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
>          && (p->flags & PMCW_FLAGS_MASK_ENA) == 0) {
>          sch->disable_cb(sch);
>      }
> -
> -    ret = 0;
> -
> -out:
> -    return ret;
> +    return IOINST_CC_EXPECTED;
>  }
>  
>  IOInstEnding css_do_xsch(SubchDev *sch)
> diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
> index 0c1efbae39..a74f6cc274 100644
> --- a/include/hw/s390x/css.h
> +++ b/include/hw/s390x/css.h
> @@ -239,7 +239,7 @@ bool css_subch_visible(SubchDev *sch);
>  void css_conditional_io_interrupt(SubchDev *sch);
>  int css_do_stsch(SubchDev *sch, SCHIB *schib);
>  bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
> -int css_do_msch(SubchDev *sch, const SCHIB *schib);
> +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *schib);
>  IOInstEnding css_do_xsch(SubchDev *sch);
>  IOInstEnding css_do_csch(SubchDev *sch);
>  IOInstEnding css_do_hsch(SubchDev *sch);
> diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
> index 8e4dacafd8..23962fbebc 100644
> --- a/target/s390x/ioinst.c
> +++ b/target/s390x/ioinst.c
> @@ -111,8 +111,6 @@ void ioinst_handle_msch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
>      SubchDev *sch;
>      SCHIB schib;
>      uint64_t addr;
> -    int ret = -ENODEV;
> -    int cc;
>      CPUS390XState *env = &cpu->env;
>      uint8_t ar;
>  
> @@ -131,24 +129,11 @@ void ioinst_handle_msch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
>      }
>      trace_ioinst_sch_id("msch", cssid, ssid, schid);
>      sch = css_find_subch(m, cssid, ssid, schid);
> -    if (sch && css_subch_visible(sch)) {
> -        ret = css_do_msch(sch, &schib);
> -    }
> -    switch (ret) {
> -    case -ENODEV:
> -        cc = 3;
> -        break;
> -    case -EBUSY:
> -        cc = 2;
> -        break;
> -    case 0:
> -        cc = 0;
> -        break;
> -    default:
> -        cc = 1;
> -        break;
> +    if (!sch || !css_subch_visible(sch)) {
> +        setcc(cpu, 3);
> +        return;
>      }
> -    setcc(cpu, cc);
> +    setcc(cpu, css_do_msch(sch, &schib));
>  }
>  
>  static void copy_orb_from_guest(ORB *dest, const ORB *src)
Thomas Huth Oct. 18, 2017, 10 a.m. UTC | #2
On 17.10.2017 16:04, Halil Pasic wrote:
> Simplify the error handling of the MSCH.  Let the code detecting the
> condition tell (in a less ambiguous way) how it's to be handled. No
> changes in behavior.

ok, so you claim no changes in behavior ...

> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> ---
>  hw/s390x/css.c         | 18 +++++-------------
>  include/hw/s390x/css.h |  2 +-
>  target/s390x/ioinst.c  | 23 ++++-------------------
>  3 files changed, 10 insertions(+), 33 deletions(-)
> 
> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> index b9e0329825..30fc236946 100644
> --- a/hw/s390x/css.c
> +++ b/hw/s390x/css.c
> @@ -1347,28 +1347,24 @@ static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
>      }
>  }
>  
> -int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
>  {
>      SCSW *s = &sch->curr_status.scsw;
>      PMCW *p = &sch->curr_status.pmcw;
>      uint16_t oldflags;
> -    int ret;
>      SCHIB schib;
>  
>      if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
> -        ret = 0;
> -        goto out;
> +        return IOINST_CC_EXPECTED;
>      }
>  
>      if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
> -        ret = -EINPROGRESS;
> -        goto out;
> +        return IOINST_CC_STATUS_PRESENT;
>      }
>  
>      if (s->ctrl &
>          (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
> -        ret = -EBUSY;
> -        goto out;
> +        return IOINST_CC_STATUS_PRESENT;
>      }

... but here you change -EBUSY (which got mapped to CC=2) to
CC_STATUS_PRESENT which means CC=1. So that's a change in behavior. i.e.
this is either a bug, or you should update the patch description with a
justification for this change in behavior.

 Thomas
Cornelia Huck Oct. 18, 2017, 10:02 a.m. UTC | #3
On Wed, 18 Oct 2017 12:00:05 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 17.10.2017 16:04, Halil Pasic wrote:
> > Simplify the error handling of the MSCH.  Let the code detecting the
> > condition tell (in a less ambiguous way) how it's to be handled. No
> > changes in behavior.  
> 
> ok, so you claim no changes in behavior ...
> 
> > Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> > ---
> >  hw/s390x/css.c         | 18 +++++-------------
> >  include/hw/s390x/css.h |  2 +-
> >  target/s390x/ioinst.c  | 23 ++++-------------------
> >  3 files changed, 10 insertions(+), 33 deletions(-)
> > 
> > diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> > index b9e0329825..30fc236946 100644
> > --- a/hw/s390x/css.c
> > +++ b/hw/s390x/css.c
> > @@ -1347,28 +1347,24 @@ static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
> >      }
> >  }
> >  
> > -int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> > +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> >  {
> >      SCSW *s = &sch->curr_status.scsw;
> >      PMCW *p = &sch->curr_status.pmcw;
> >      uint16_t oldflags;
> > -    int ret;
> >      SCHIB schib;
> >  
> >      if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
> > -        ret = 0;
> > -        goto out;
> > +        return IOINST_CC_EXPECTED;
> >      }
> >  
> >      if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
> > -        ret = -EINPROGRESS;
> > -        goto out;
> > +        return IOINST_CC_STATUS_PRESENT;
> >      }
> >  
> >      if (s->ctrl &
> >          (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
> > -        ret = -EBUSY;
> > -        goto out;
> > +        return IOINST_CC_STATUS_PRESENT;
> >      }  
> 
> ... but here you change -EBUSY (which got mapped to CC=2) to
> CC_STATUS_PRESENT which means CC=1. So that's a change in behavior. i.e.
> this is either a bug, or you should update the patch description with a
> justification for this change in behavior.

Indeed, that's a bug. We still want cc 2.
Halil Pasic Oct. 18, 2017, 11:01 a.m. UTC | #4
On 10/18/2017 12:02 PM, Cornelia Huck wrote:
> On Wed, 18 Oct 2017 12:00:05 +0200
> Thomas Huth <thuth@redhat.com> wrote:
> 
>> On 17.10.2017 16:04, Halil Pasic wrote:
>>> Simplify the error handling of the MSCH.  Let the code detecting the
>>> condition tell (in a less ambiguous way) how it's to be handled. No
>>> changes in behavior.  
>>
>> ok, so you claim no changes in behavior ...
>>
>>> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
>>> ---
>>>  hw/s390x/css.c         | 18 +++++-------------
>>>  include/hw/s390x/css.h |  2 +-
>>>  target/s390x/ioinst.c  | 23 ++++-------------------
>>>  3 files changed, 10 insertions(+), 33 deletions(-)
>>>
>>> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
>>> index b9e0329825..30fc236946 100644
>>> --- a/hw/s390x/css.c
>>> +++ b/hw/s390x/css.c
>>> @@ -1347,28 +1347,24 @@ static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
>>>      }
>>>  }
>>>  
>>> -int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
>>> +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
>>>  {
>>>      SCSW *s = &sch->curr_status.scsw;
>>>      PMCW *p = &sch->curr_status.pmcw;
>>>      uint16_t oldflags;
>>> -    int ret;
>>>      SCHIB schib;
>>>  
>>>      if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
>>> -        ret = 0;
>>> -        goto out;
>>> +        return IOINST_CC_EXPECTED;
>>>      }
>>>  
>>>      if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
>>> -        ret = -EINPROGRESS;
>>> -        goto out;
>>> +        return IOINST_CC_STATUS_PRESENT;
>>>      }
>>>  
>>>      if (s->ctrl &
>>>          (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
>>> -        ret = -EBUSY;
>>> -        goto out;
>>> +        return IOINST_CC_STATUS_PRESENT;
>>>      }  
>>
>> ... but here you change -EBUSY (which got mapped to CC=2) to
>> CC_STATUS_PRESENT which means CC=1. So that's a change in behavior. i.e.
>> this is either a bug, or you should update the patch description with a
>> justification for this change in behavior.
> 
> Indeed, that's a bug. We still want cc 2.
> 

Agree, it is a bug. It was OK in v1 but was already buggy in
v2.

Conny can you fix this up as well please?

Thanks in advance!

Halil
Dong Jia Shi Oct. 19, 2017, 6:23 a.m. UTC | #5
* Halil Pasic <pasic@linux.vnet.ibm.com> [2017-10-18 13:01:03 +0200]:

> 
> 
> On 10/18/2017 12:02 PM, Cornelia Huck wrote:
> > On Wed, 18 Oct 2017 12:00:05 +0200
> > Thomas Huth <thuth@redhat.com> wrote:
> > 
> >> On 17.10.2017 16:04, Halil Pasic wrote:
> >>> Simplify the error handling of the MSCH.  Let the code detecting the
> >>> condition tell (in a less ambiguous way) how it's to be handled. No
> >>> changes in behavior.  
> >>
> >> ok, so you claim no changes in behavior ...
> >>
> >>> Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
> >>> ---
> >>>  hw/s390x/css.c         | 18 +++++-------------
> >>>  include/hw/s390x/css.h |  2 +-
> >>>  target/s390x/ioinst.c  | 23 ++++-------------------
> >>>  3 files changed, 10 insertions(+), 33 deletions(-)
> >>>
> >>> diff --git a/hw/s390x/css.c b/hw/s390x/css.c
> >>> index b9e0329825..30fc236946 100644
> >>> --- a/hw/s390x/css.c
> >>> +++ b/hw/s390x/css.c
> >>> @@ -1347,28 +1347,24 @@ static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
> >>>      }
> >>>  }
> >>>  
> >>> -int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> >>> +IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
> >>>  {
> >>>      SCSW *s = &sch->curr_status.scsw;
> >>>      PMCW *p = &sch->curr_status.pmcw;
> >>>      uint16_t oldflags;
> >>> -    int ret;
> >>>      SCHIB schib;
> >>>  
> >>>      if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
> >>> -        ret = 0;
> >>> -        goto out;
> >>> +        return IOINST_CC_EXPECTED;
> >>>      }
> >>>  
> >>>      if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
> >>> -        ret = -EINPROGRESS;
> >>> -        goto out;
> >>> +        return IOINST_CC_STATUS_PRESENT;
> >>>      }
> >>>  
> >>>      if (s->ctrl &
> >>>          (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
> >>> -        ret = -EBUSY;
> >>> -        goto out;
> >>> +        return IOINST_CC_STATUS_PRESENT;
> >>>      }  
> >>
> >> ... but here you change -EBUSY (which got mapped to CC=2) to
> >> CC_STATUS_PRESENT which means CC=1. So that's a change in behavior. i.e.
> >> this is either a bug, or you should update the patch description with a
> >> justification for this change in behavior.
> > 
> > Indeed, that's a bug. We still want cc 2.
> > 
> 
> Agree, it is a bug. It was OK in v1 but was already buggy in
> v2.
> 
> Conny can you fix this up as well please?
> 
> Thanks in advance!
> 
I saw Conny fixed this in her branch. So:
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
diff mbox

Patch

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index b9e0329825..30fc236946 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1347,28 +1347,24 @@  static void copy_schib_from_guest(SCHIB *dest, const SCHIB *src)
     }
 }
 
-int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
+IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
 {
     SCSW *s = &sch->curr_status.scsw;
     PMCW *p = &sch->curr_status.pmcw;
     uint16_t oldflags;
-    int ret;
     SCHIB schib;
 
     if (!(sch->curr_status.pmcw.flags & PMCW_FLAGS_MASK_DNV)) {
-        ret = 0;
-        goto out;
+        return IOINST_CC_EXPECTED;
     }
 
     if (s->ctrl & SCSW_STCTL_STATUS_PEND) {
-        ret = -EINPROGRESS;
-        goto out;
+        return IOINST_CC_STATUS_PRESENT;
     }
 
     if (s->ctrl &
         (SCSW_FCTL_START_FUNC|SCSW_FCTL_HALT_FUNC|SCSW_FCTL_CLEAR_FUNC)) {
-        ret = -EBUSY;
-        goto out;
+        return IOINST_CC_STATUS_PRESENT;
     }
 
     copy_schib_from_guest(&schib, orig_schib);
@@ -1395,11 +1391,7 @@  int css_do_msch(SubchDev *sch, const SCHIB *orig_schib)
         && (p->flags & PMCW_FLAGS_MASK_ENA) == 0) {
         sch->disable_cb(sch);
     }
-
-    ret = 0;
-
-out:
-    return ret;
+    return IOINST_CC_EXPECTED;
 }
 
 IOInstEnding css_do_xsch(SubchDev *sch)
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index 0c1efbae39..a74f6cc274 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -239,7 +239,7 @@  bool css_subch_visible(SubchDev *sch);
 void css_conditional_io_interrupt(SubchDev *sch);
 int css_do_stsch(SubchDev *sch, SCHIB *schib);
 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
-int css_do_msch(SubchDev *sch, const SCHIB *schib);
+IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *schib);
 IOInstEnding css_do_xsch(SubchDev *sch);
 IOInstEnding css_do_csch(SubchDev *sch);
 IOInstEnding css_do_hsch(SubchDev *sch);
diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index 8e4dacafd8..23962fbebc 100644
--- a/target/s390x/ioinst.c
+++ b/target/s390x/ioinst.c
@@ -111,8 +111,6 @@  void ioinst_handle_msch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
     SubchDev *sch;
     SCHIB schib;
     uint64_t addr;
-    int ret = -ENODEV;
-    int cc;
     CPUS390XState *env = &cpu->env;
     uint8_t ar;
 
@@ -131,24 +129,11 @@  void ioinst_handle_msch(S390CPU *cpu, uint64_t reg1, uint32_t ipb)
     }
     trace_ioinst_sch_id("msch", cssid, ssid, schid);
     sch = css_find_subch(m, cssid, ssid, schid);
-    if (sch && css_subch_visible(sch)) {
-        ret = css_do_msch(sch, &schib);
-    }
-    switch (ret) {
-    case -ENODEV:
-        cc = 3;
-        break;
-    case -EBUSY:
-        cc = 2;
-        break;
-    case 0:
-        cc = 0;
-        break;
-    default:
-        cc = 1;
-        break;
+    if (!sch || !css_subch_visible(sch)) {
+        setcc(cpu, 3);
+        return;
     }
-    setcc(cpu, cc);
+    setcc(cpu, css_do_msch(sch, &schib));
 }
 
 static void copy_orb_from_guest(ORB *dest, const ORB *src)