Re: [Qemu-devel] [PATCH V9 2/6] memory: use sparse feature define RAM_FLAG.

[Yi Zhang <yi.z.zhang@linux.intel.com>]

On 2019-01-21 at 15:24:17 -0500, Michael S. Tsirkin wrote:
> On Mon, Jan 21, 2019 at 02:35:57PM +0800, Yi Zhang wrote:
> > On 2019-01-16 at 10:55:33 -0500, Michael S. Tsirkin wrote:
> > > On Wed, Jan 16, 2019 at 04:10:29PM +0800, Zhang Yi wrote:
> > > > Signed-off-by: Zhang Yi <yi.z.zhang@linux.intel.com>
> > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > 
> > > OK so if you apply this patch, do you get
> > > any sparse warning at all?
> > Didn't get any sparse warning.
> 
> 
> The reason I find it strange is because you then go on
> to assign these flags to an untagged unint32_t.
> 
> Did you forget to configure with sparse enabled maybe?
Ah.. Right, Sorry for that I don't have much knowledge about this
feature and how to use that. I will split this effort out and focus
MAP_SYNC work. 

Thanks Micheal.
> 
> 
> > > 
> > > If not how come?
> > > 
> > > And we need to ask patchew maintainers to 
> > > 
> > > Overall I'd suggest that since you no longer need
> > > a new RAM flag, split this effort out and finish
> > > MAP_SYNC work first.
> > Ok, Will
> > > 
> > > 
> > > > ---
> > > >  include/exec/memory.h | 12 ++++++------
> > > >  include/qemu/osdep.h  |  9 +++++++++
> > > >  2 files changed, 15 insertions(+), 6 deletions(-)
> > > > 
> > > > diff --git a/include/exec/memory.h b/include/exec/memory.h
> > > > index 667466b..03824d9 100644
> > > > --- a/include/exec/memory.h
> > > > +++ b/include/exec/memory.h
> > > > @@ -104,27 +104,27 @@ struct IOMMUNotifier {
> > > >  typedef struct IOMMUNotifier IOMMUNotifier;
> > > >  
> > > >  /* RAM is pre-allocated and passed into qemu_ram_alloc_from_ptr */
> > > > -#define RAM_PREALLOC   (1 << 0)
> > > > +#define RAM_PREALLOC ((QEMU_FORCE QemuMmapFlags) (1 << 0))
> > > >  
> > > >  /* RAM is mmap-ed with MAP_SHARED */
> > > > -#define RAM_SHARED     (1 << 1)
> > > > +#define RAM_SHARED ((QEMU_FORCE QemuMmapFlags) (1 << 1))
> > > >  
> > > >  /* Only a portion of RAM (used_length) is actually used, and migrated.
> > > >   * This used_length size can change across reboots.
> > > >   */
> > > > -#define RAM_RESIZEABLE (1 << 2)
> > > > +#define RAM_RESIZEABLE ((QEMU_FORCE QemuMmapFlags) (1 << 2))
> > > >  
> > > >  /* UFFDIO_ZEROPAGE is available on this RAMBlock to atomically
> > > >   * zero the page and wake waiting processes.
> > > >   * (Set during postcopy)
> > > >   */
> > > > -#define RAM_UF_ZEROPAGE (1 << 3)
> > > > +#define RAM_UF_ZEROPAGE ((QEMU_FORCE QemuMmapFlags) (1 << 3))
> > > >  
> > > >  /* RAM can be migrated */
> > > > -#define RAM_MIGRATABLE (1 << 4)
> > > > +#define RAM_MIGRATABLE ((QEMU_FORCE QemuMmapFlags) (1 << 4))
> > > >  
> > > >  /* RAM is a persistent kind memory */
> > > > -#define RAM_PMEM (1 << 5)
> > > > +#define RAM_PMEM ((QEMU_FORCE QemuMmapFlags) (1 << 5))
> > > >  
> > > >  static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn,
> > > >                                         IOMMUNotifierFlag flags,
> > > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> > > > index 3bf48bc..457d24e 100644
> > > > --- a/include/qemu/osdep.h
> > > > +++ b/include/qemu/osdep.h
> > > > @@ -185,6 +185,15 @@ extern int daemon(int, int);
> > > >  #define ESHUTDOWN 4099
> > > >  #endif
> > > >  
> > > > +#ifdef __CHECKER__
> > > > +#define QEMU_BITWISE __attribute__((bitwise))
> > > > +#define QEMU_FORCE   __attribute__((force))
> > > > +#else
> > > > +#define QEMU_BITWISE
> > > > +#define QEMU_FORCE
> > > > +#endif
> > > > +
> > > > +typedef unsigned QEMU_BITWISE QemuMmapFlags;
> > > >  /* time_t may be either 32 or 64 bits depending on the host OS, and
> > > >   * can be either signed or unsigned, so we can't just hardcode a
> > > >   * specific maximum value. This is not a C preprocessor constant,
> > > > -- 
> > > > 2.7.4
>