Re: [PATCH v2 1/6] host-utils: fix ssub32/64_saturate return type and clamp direction

On 8/5/2026 11:32 PM, Brian Cain wrote:
> ssub32_saturate() and ssub64_saturate() were declared to return bool
> instead of int32_t/int64_t, and clamped to the wrong bound on overflow.
>
> Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
> Cc: [email protected]
> Fixes: 16495533131 ("host-utils: Introduce signed saturation primitives")
> Reviewed-by: Pierrick Bouvier <[email protected]>
> Signed-off-by: Brian Cain <[email protected]>
> ---

Michael,

     I think this patch is a good candidate fix for -stable.

-Brian


>   include/qemu/host-utils.h | 24 ++++++++++++------------
>   1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
> index 2e8da7fb3d0..1db9dbb138e 100644
> --- a/include/qemu/host-utils.h
> +++ b/include/qemu/host-utils.h
> @@ -607,10 +607,10 @@ static inline bool umul64_overflow(uint64_t x, uint64_t y, uint64_t *ret)
>   }
>   
>   /**
> - * sadd32_saturate - addition with saturation
> + * sadd32_saturate - 32-bit signed addition with saturation
>    * @x, @y: addends
>    *
> - * Computes @x + @y, and saturates rathern than truncating the result.
> + * Computes @x + @y, and saturates rather than truncating the result.
>    */
>   static inline int32_t sadd32_saturate(int32_t x, int32_t y)
>   {
> @@ -622,10 +622,10 @@ static inline int32_t sadd32_saturate(int32_t x, int32_t y)
>   }
>   
>   /**
> - * sadd64_saturate - addition with saturation
> + * sadd64_saturate - 64-bit signed addition with saturation
>    * @x, @y: addends
>    *
> - * Computes @x + @y, and saturates rathern than truncating the result.
> + * Computes @x + @y, and saturates rather than truncating the result.
>    */
>   static inline int64_t sadd64_saturate(int64_t x, int64_t y)
>   {
> @@ -637,31 +637,31 @@ static inline int64_t sadd64_saturate(int64_t x, int64_t y)
>   }
>   
>   /**
> - * ssub32_saturate - subtraction with saturation
> + * ssub32_saturate - 32-bit signed subtraction with saturation
>    * @x, @y: addends
>    *
> - * Computes @x + @y, and saturates rathern than truncating the result.
> + * Computes @x - @y, and saturates rather than truncating the result.
>    */
> -static inline bool ssub32_saturate(int32_t x, int32_t y)
> +static inline int32_t ssub32_saturate(int32_t x, int32_t y)
>   {
>       int32_t ret;
>       if (ssub32_overflow(x, y, &ret)) {
> -        ret = x < 0 ? INT32_MAX : INT32_MIN;
> +        ret = x < 0 ? INT32_MIN : INT32_MAX;
>       }
>       return ret;
>   }
>   
>   /**
> - * ssub64_saturate - subtraction with saturation
> + * ssub64_saturate - 64-bit signed subtraction with saturation
>    * @x, @y: addends
>    *
> - * Computes @x + @y, and saturates rathern than truncating the result.
> + * Computes @x - @y, and saturates rather than truncating the result.
>    */
> -static inline bool ssub64_saturate(int64_t x, int64_t y)
> +static inline int64_t ssub64_saturate(int64_t x, int64_t y)
>   {
>       int64_t ret;
>       if (ssub64_overflow(x, y, &ret)) {
> -        ret = x < 0 ? INT64_MAX : INT64_MIN;
> +        ret = x < 0 ? INT64_MIN : INT64_MAX;
>       }
>       return ret;
>   }