Re: [PULL 04/11] xen-mapcache: Remove 32bit support

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On 9/18/26 12:39 PM, Peter Xu wrote:
> QEMU has switched to 64bit-only hosts for all system emulations.
>
> Reviewed-by: Richard Henderson <richard.henderson@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/20260818172012.3052821-5-peterx@xxxxxxxxxx
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Anthony PERARD <anthony@xxxxxxxxxxxxxx>
> Cc: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxxxx>
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
> ---
>   hw/xen/xen-mapcache.c | 12 ++----------
>   1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c
> index 85cf0cf359..e30c07c2ee 100644
> --- a/hw/xen/xen-mapcache.c
> +++ b/hw/xen/xen-mapcache.c
> @@ -26,11 +26,7 @@
>   #include <xenevtchn.h>
>   #include <xengnttab.h>
>   
> -#if HOST_LONG_BITS == 32
> -#  define MCACHE_MAX_SIZE     (1UL<<31) /* 2GB Cap */
> -#else
> -#  define MCACHE_MAX_SIZE     (1UL<<35) /* 32GB Cap */
> -#endif
> +#define MCACHE_MAX_SIZE     (1UL << 35) /* 32GB Cap */
>   
>   /* This is the size of the virtual address space reserve to QEMU that will not
>    * be use by MapCache.
> @@ -151,11 +147,7 @@ void xen_map_cache_init(phys_offset_to_gaddr_t f, void 
> *opaque)
>           exit(EXIT_FAILURE);
>       }
>   
> -    if (HOST_LONG_BITS == 32) {
> -        bucket_shift = 16;
> -    } else {
> -        bucket_shift = 20;
> -    }
> +    bucket_shift = 20;
>   
>       if (geteuid() == 0) {
>           rlimit_as.rlim_cur = RLIM_INFINITY;
Using a local variable here to store a constant is a bit weird and its only use
is to be stored as MapCache.bucket_shift and MapCache.bucket_size which are
effectively constant. Not sure why this isn't just a couple of #defines at the
top and used everywhere bucket_shift and bucket_size is needed. Perhaps that is
further cleanup to be done separately...

Ross