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

[Alexander Graf <agraf@suse.de>]

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