Re: [Qemu-devel] [PATCH] i386/kvm: Fix build with -m32

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Jun 24, 2019 at 09:02:14PM +0200, Max Reitz wrote:
> find_next_bit() takes a pointer of type "const unsigned long *", but the
> first argument passed here is a "uint64_t *".  These types are
> incompatible when compiling qemu with -m32.
> 
> Just cast it to "const void *", find_next_bit() works fine with any type
> on little-endian hosts (which x86 is).
> 
> Fixes: c686193072a47032d83cb4e131dc49ae30f9e5d
> Signed-off-by: Max Reitz <mreitz@redhat.com>

Why not declare kvm_hyperv_properties.dependencies with the right
type for bitmaps, using
  unsigned long dependencies[BITS_TO_LONGS(64)]
?

> ---
>  target/i386/kvm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
> index e4b4f5756a..1b5f3b1c00 100644
> --- a/target/i386/kvm.c
> +++ b/target/i386/kvm.c
> @@ -1050,7 +1050,7 @@ static int hv_cpuid_check_and_set(CPUState *cs, struct kvm_cpuid2 *cpuid,
>      }
>  
>      deps = kvm_hyperv_properties[feature].dependencies;
> -    while ((dep_feat = find_next_bit(&deps, 64, dep_feat)) < 64) {
> +    while ((dep_feat = find_next_bit((const void *)&deps, 64, dep_feat)) < 64) {
>          if (!(hyperv_feat_enabled(cpu, dep_feat))) {
>                  fprintf(stderr,
>                          "Hyper-V %s requires Hyper-V %s\n",
> -- 
> 2.21.0
> 

-- 
Eduardo