[Qemu-devel] Re: [PATCH] add VMSTATE_BOOL

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Nov 01, 2010 at 03:51:54PM +0100, Gerd Hoffmann wrote:
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/hw.h  |   14 ++++++++++++++
>  savevm.c |   21 +++++++++++++++++++++
>  2 files changed, 35 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/hw.h b/hw/hw.h
> index e935364..234c713 100644
> --- a/hw/hw.h
> +++ b/hw/hw.h
> @@ -333,6 +333,8 @@ struct VMStateDescription {
>      const VMStateSubsection *subsections;
>  };
>  
> +extern const VMStateInfo vmstate_info_bool;
> +
>  extern const VMStateInfo vmstate_info_int8;
>  extern const VMStateInfo vmstate_info_int16;
>  extern const VMStateInfo vmstate_info_int32;
> @@ -613,6 +615,9 @@ extern const VMStateDescription vmstate_i2c_slave;
>  #define VMSTATE_STRUCT_POINTER(_field, _state, _vmsd, _type)          \
>      VMSTATE_STRUCT_POINTER_TEST(_field, _state, NULL, _vmsd, _type)
>  
> +#define VMSTATE_BOOL_V(_f, _s, _v)                                    \
> +    VMSTATE_SINGLE(_f, _s, _v, vmstate_info_bool, bool)
> +
>  #define VMSTATE_INT8_V(_f, _s, _v)                                    \
>      VMSTATE_SINGLE(_f, _s, _v, vmstate_info_int8, int8_t)
>  #define VMSTATE_INT16_V(_f, _s, _v)                                   \
> @@ -631,6 +636,9 @@ extern const VMStateDescription vmstate_i2c_slave;
>  #define VMSTATE_UINT64_V(_f, _s, _v)                                  \
>      VMSTATE_SINGLE(_f, _s, _v, vmstate_info_uint64, uint64_t)
>  
> +#define VMSTATE_BOOL(_f, _s)                                          \
> +    VMSTATE_BOOL_V(_f, _s, 0)
> +
>  #define VMSTATE_INT8(_f, _s)                                          \
>      VMSTATE_INT8_V(_f, _s, 0)
>  #define VMSTATE_INT16(_f, _s)                                         \
> @@ -685,6 +693,12 @@ extern const VMStateDescription vmstate_i2c_slave;
>  #define VMSTATE_PTIMER(_f, _s)                                        \
>      VMSTATE_PTIMER_V(_f, _s, 0)
>  
> +#define VMSTATE_BOOL_ARRAY_V(_f, _s, _n, _v)                         \
> +    VMSTATE_ARRAY(_f, _s, _n, _v, vmstate_info_bool, bool)
> +
> +#define VMSTATE_BOOL_ARRAY(_f, _s, _n)                               \
> +    VMSTATE_BOOL_ARRAY_V(_f, _s, _n, 0)
> +

Why don't we pack the bits?

>  #define VMSTATE_UINT16_ARRAY_V(_f, _s, _n, _v)                         \
>      VMSTATE_ARRAY(_f, _s, _n, _v, vmstate_info_uint16, uint16_t)
>  
> diff --git a/savevm.c b/savevm.c
> index 10057f3..14268ea 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -675,6 +675,27 @@ uint64_t qemu_get_be64(QEMUFile *f)
>      return v;
>  }
>  
> +/* bool */
> +
> +static int get_bool(QEMUFile *f, void *pv, size_t size)
> +{
> +    bool *v = pv;
> +    *v = qemu_get_byte(f);
> +    return 0;

We must really validate that the value is 0 or 1.
If it's not, we will get undefined behaviour.

> +}
> +
> +static void put_bool(QEMUFile *f, void *pv, size_t size)
> +{
> +    bool *v = pv;
> +    qemu_put_byte(f, *v);

Is there a guarantee that bool is a single byte, BTW?

> +}
> +
> +const VMStateInfo vmstate_info_bool = {
> +    .name = "bool",
> +    .get  = get_bool,
> +    .put  = put_bool,
> +};
> +
>  /* 8 bit int */
>  
>  static int get_int8(QEMUFile *f, void *pv, size_t size)
> -- 
> 1.7.1
>