Re: [Qemu-devel] [PATCH v2 53/54] qapi: make query-cpu-model-expansion depend on s390 or x86

[Eduardo Habkost]

On Wed, Aug 23, 2017 at 09:58:59AM -0400, Marc-André Lureau wrote:
> Hi
> 
> ----- Original Message -----
> > On Wed, Aug 23, 2017 at 06:21:16AM -0400, Marc-André Lureau wrote:
> > > Hi
> > > 
> > > ----- Original Message -----
> > > > On Tue, Aug 22, 2017 at 03:22:54PM +0200, Marc-André Lureau wrote:
> > > > > Signed-off-by: Marc-André Lureau <address@hidden>
> > > > > ---
> > > > >  qapi-schema.json                       |  4 +++-
> > > > >  include/sysemu/arch_init.h             |  3 ---
> > > > >  monitor.c                              |  3 ---
> > > > >  qmp.c                                  |  7 -------
> > > > >  stubs/arch-query-cpu-model-expansion.c | 12 ------------
> > > > >  target/i386/cpu.c                      |  2 +-
> > > > >  target/s390x/cpu_models.c              |  3 ++-
> > > > >  stubs/Makefile.objs                    |  1 -
> > > > >  8 files changed, 6 insertions(+), 29 deletions(-)
> > > > >  delete mode 100644 stubs/arch-query-cpu-model-expansion.c
> > > > > 
> > > > > diff --git a/qapi-schema.json b/qapi-schema.json
> > > > > index 6c1adb35b5..127a2c71c6 100644
> > > > > --- a/qapi-schema.json
> > > > > +++ b/qapi-schema.json
> > > > > @@ -4535,7 +4535,9 @@
> > > > >  { 'command': 'query-cpu-model-expansion',
> > > > >    'data': { 'type': 'CpuModelExpansionType',
> > > > >              'model': 'CpuModelInfo' },
> > > > > -  'returns': 'CpuModelExpansionInfo' }
> > > > > +  'returns': 'CpuModelExpansionInfo',
> > > > > +  'if': ['defined(NEED_CPU_H)',
> > > > > +         'defined(TARGET_S390X) || defined(TARGET_I386)']}
> > > > 
> > > > Maybe this is already documented somewhere in the series (I'm
> > > > still going through the other patches), but: why exactly is
> > > > 'defined(NEED_CPU_H)' in the list, too?
> > > 
> > > The point of this series is to make qapi schema configurable.
> > > 
> > > Some types/commands/events are target-specifc. In order to
> > > #ifdef on poisoined symbols, we make most of QAPI generated
> > > code built per-target in patch 49/54. But the common code still
> > > need to compile some units, that's why #ifdef NEED_CPU_U. The
> > > clean solution is probably to split the generated schema to
> > > common & per-target, that's not covered in the series.
> > 
> > I see.  I'm worried about one thing: what if the QMP dispatch
> > code is incorrectly moved back to common code later?  It will
> > silently skip all the arch-dependent commands without any
> > warnings.
> > 
> > e.g.: I just applied the following change on top of your series,
> > and all arch-dependent commands are silently skipped:
> > 
> 
> And it doesn't fail a full/all-arch make check? It probably should.

I don't know, I will test it.

> 
> >   diff --git a/Makefile.objs b/Makefile.objs
> >   index 2664720..24a4ea0 100644
> >   --- a/Makefile.objs
> >   +++ b/Makefile.objs
> >   @@ -2,7 +2,7 @@
> >    # Common libraries for tools and emulators
> >    stub-obj-y = stubs/ crypto/
> >    util-obj-y = util/ qobject/ qapi/
> >   -util-obj-y += qapi-types.o qapi-visit.o
> >   +util-obj-y += qmp-introspect.o qapi-types.o qapi-visit.o qapi-event.o
> >    
> >    chardev-obj-y = chardev/
> >    
> >   @@ -72,6 +72,13 @@ common-obj-y += chardev/
> >    common-obj-$(CONFIG_SECCOMP) += qemu-seccomp.o
> >    
> >    common-obj-$(CONFIG_FDT) += device_tree.o
> >   +
> >   +######################################################################
> >   +# qapi
> >   +
> >   +common-obj-y += qmp-marshal.o
> >   +common-obj-y += qmp-introspect.o
> >   +common-obj-y += qmp.o hmp.o
> >    endif
> >    
> >    #######################################################################
> >   diff --git a/Makefile.target b/Makefile.target
> >   index c5f8ded..7f42c45 100644
> >   --- a/Makefile.target
> >   +++ b/Makefile.target
> >   @@ -157,10 +157,6 @@ endif
> >    
> >    GENERATED_FILES += hmp-commands.h hmp-commands-info.h
> >    
> >   -obj-y += qmp-introspect.o qapi-types.o qapi-visit.o qapi-event.o
> >   -obj-y += qmp-marshal.o qmp-introspect.o
> >   -obj-y += qmp.o hmp.o
> >   -
> >    endif # CONFIG_SOFTMMU
> >    
> >    # Workaround for http://gcc.gnu.org/PR55489, see configure.
> > 
> > 
> > We wouldn't need to check NEED_CPU_H at all if the condition on
> > QMP commands affect only the actual QMP dispatch code, and not
> > the generated types or declarations.  e.g.:
> > 
> 
> Possible, but is it desirable? I would prefer if all the
> generated code would be configured, so we can more easily
> compile out dead code when disabling a feature. 

That's a valid question.

A check for defined(NEED_CPU_H) inside a .c file still feels
wrong to me.  But if "make check" will detect a mistake like the
one above and QAPI maintainers don't mind, I won't mind either.


> > 
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 194859f..67b46ad 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -3578,7 +3578,7 @@
> >  ##
> >  { 'command': 'dump-skeys',
> >    'data': { 'filename': 'str' },
> > -  'if': ['defined(NEED_CPU_H)', 'defined(TARGET_S390X)']}
> > +  'if': ['defined(TARGET_S390X)']}
> >  
> >  ##
> >  # @netdev_add:
> > @@ -4434,8 +4434,7 @@
> >  # Since: 1.2.0
> >  ##
> >  { 'command': 'query-cpu-definitions', 'returns': ['CpuDefinitionInfo'],
> > -  'if': ['defined(NEED_CPU_H)',
> > -         'defined(TARGET_PPC) || defined(TARGET_ARM) || 
> > defined(TARGET_I386)
> > || defined(TARGET_S390X)'] }
> > +  'if': ['defined(TARGET_PPC) || defined(TARGET_ARM) || 
> > defined(TARGET_I386)
> > || defined(TARGET_S390X)'] }
> >  
> >  ##
> >  # @CpuModelInfo:
> > @@ -4538,8 +4537,7 @@
> >    'data': { 'type': 'CpuModelExpansionType',
> >              'model': 'CpuModelInfo' },
> >    'returns': 'CpuModelExpansionInfo',
> > -  'if': ['defined(NEED_CPU_H)',
> > -         'defined(TARGET_S390X) || defined(TARGET_I386)']}
> > +  'if': ['defined(TARGET_S390X) || defined(TARGET_I386)']}
> >  
> >  ##
> >  # @CpuModelCompareResult:
> > @@ -4627,7 +4625,7 @@
> >  { 'command': 'query-cpu-model-comparison',
> >    'data': { 'modela': 'CpuModelInfo', 'modelb': 'CpuModelInfo' },
> >    'returns': 'CpuModelCompareInfo',
> > -  'if': ['defined(NEED_CPU_H)', 'defined(TARGET_S390X)']}
> > +  'if': ['defined(TARGET_S390X)']}
> >  
> >  
> >  ##
> > @@ -4681,7 +4679,7 @@
> >    'data': { 'modela': 'CpuModelInfo',
> >              'modelb': 'CpuModelInfo' },
> >    'returns': 'CpuModelBaselineInfo',
> > -  'if': ['defined(NEED_CPU_H)', 'defined(TARGET_S390X)']}
> > +  'if': ['defined(TARGET_S390X)']}
> >  
> >  ##
> >  # @AddfdInfo:
> > @@ -6303,7 +6301,7 @@
> >  #
> >  ##
> >  { 'command': 'rtc-reset-reinjection',
> > -  'if': ['defined(NEED_CPU_H)', 'defined(TARGET_I386)'] }
> > +  'if': ['defined(TARGET_I386)'] }
> >  
> >  # Rocker ethernet network switch
> >  { 'include': 'qapi/rocker.json' }
> > @@ -6466,7 +6464,7 @@
> >  #
> >  ##
> >  { 'command': 'query-gic-capabilities', 'returns': ['GICCapability'],
> > -  'if': ['defined(NEED_CPU_H)', 'defined(TARGET_ARM)']}
> > +  'if': ['defined(TARGET_ARM)']}
> >  
> >  ##
> >  # @CpuInstanceProperties:
> > diff --git a/scripts/qapi.py b/scripts/qapi.py
> > index bcd8d37..769a730 100644
> > --- a/scripts/qapi.py
> > +++ b/scripts/qapi.py
> > @@ -1720,8 +1720,7 @@ class QAPISchema(object):
> >          ifcond = expr.get('if')
> >          if isinstance(data, OrderedDict):
> >              data = self._make_implicit_object_type(
> > -                name, info, doc, 'arg', self._make_members(data, info),
> > -                ifcond)
> > +                name, info, doc, 'arg', self._make_members(data, info))
> >          if isinstance(rets, list):
> >              assert len(rets) == 1
> >              rets = self._make_array_type(rets[0], info)
> > diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
> > index db45415..2baa73f 100644
> > --- a/scripts/qapi-commands.py
> > +++ b/scripts/qapi-commands.py
> > @@ -228,7 +228,7 @@ class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
> >          self.defn = None
> >          self._regy = None
> >          self._visited_ret_types = None
> > -        self.if_members = ['decl', 'defn', '_regy']
> > +        self.if_members = ['defn', '_regy']
> >  
> >      def visit_begin(self, schema):
> >          self.decl = ''
> > 
> > 
> > --
> > Eduardo
> > 

-- 
Eduardo