Re: [Qemu-devel] [PATCH v8 09/20] exec: introduce target_words_bigendian() helper

[Greg Kurz <gkurz@linux.vnet.ibm.com>]

On Fri, 13 Jun 2014 13:41:42 +0200
Alexander Graf <agraf@suse.de> wrote:
> 
> On 13.06.14 13:21, Greg Kurz wrote:
> > We currently have a virtio_is_big_endian() helper that provides the target
> > endianness to the virtio code. As of today, the helper returns a fixed
> > compile-time value. Of course, this will have to change if we want to
> > support target endianness changes at run-time.
> >
> > Let's move the TARGET_WORDS_BIGENDIAN bits out to a new helper and have
> > virtio_is_big_endian() implemented on top of it.
> >
> > This patch doesn't change any functionality.
> >
> > Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> > ---
> >   exec.c                     |   11 +----------
> >   hw/virtio/virtio-pci.c     |    3 ---
> >   include/exec/cpu-common.h  |    1 +
> >   include/hw/virtio/virtio.h |    5 +++++
> >   4 files changed, 7 insertions(+), 13 deletions(-)
> >
> > diff --git a/exec.c b/exec.c
> > index 4e179a6..a7d4431 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -2738,14 +2738,7 @@ int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
> >   }
> >   #endif
> >   
> > -#if !defined(CONFIG_USER_ONLY)
> > -
> > -/*
> > - * A helper function for the _utterly broken_ virtio device model to find out if
> > - * it's running on a big endian machine. Don't do this at home kids!
> > - */
> > -bool virtio_is_big_endian(void);
> > -bool virtio_is_big_endian(void)
> > +bool target_words_bigendian(void)
> >   {
> >   #if defined(TARGET_WORDS_BIGENDIAN)
> >       return true;
> > @@ -2754,8 +2747,6 @@ bool virtio_is_big_endian(void)
> >   #endif
> >   }
> >   
> > -#endif
> > -
> >   #ifndef CONFIG_USER_ONLY
> >   bool cpu_physical_memory_is_io(hwaddr phys_addr)
> >   {
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index ce97514..390c8d2 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -89,9 +89,6 @@
> >   /* Flags track per-device state like workarounds for quirks in older guests. */
> >   #define VIRTIO_PCI_FLAG_BUS_MASTER_BUG  (1 << 0)
> >   
> > -/* HACK for virtio to determine if it's running a big endian guest */
> > -bool virtio_is_big_endian(void);
> > -
> >   static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
> >                                  VirtIOPCIProxy *dev);
> >   
> > diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> > index a21b65a..eb798c1 100644
> > --- a/include/exec/cpu-common.h
> > +++ b/include/exec/cpu-common.h
> > @@ -122,4 +122,5 @@ void qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque);
> >   
> >   #endif
> >   
> > +bool target_words_bigendian(void);
> 
> Please don't make this function globally available - usually no code in 
> hw/ should know about this except for virtio. Put it in a virtio header 
> instead.
> 
> 
> Alex
> 

Oops... sure I'll fix that.

-- 
Gregory Kurz                                     kurzgreg@fr.ibm.com
                                                 gkurz@linux.vnet.ibm.com
Software Engineer @ IBM/Meiosys                  http://www.ibm.com
Tel +33 (0)562 165 496

"Anarchy is about taking complete responsibility for yourself."
        Alan Moore.