Re: [PATCH] x86/ucode: Support discrete modules being CPIO archives

[Jan Beulich <jbeulich@xxxxxxxx>]

On 27.01.2026 15:34, Andrew Cooper wrote:
> --- a/xen/arch/x86/cpu/microcode/core.c
> +++ b/xen/arch/x86/cpu/microcode/core.c
> @@ -760,6 +760,7 @@ static int __init early_microcode_load(struct boot_info 
> *bi)
>      void *data = NULL;
>      size_t size;
>      struct microcode_patch *patch;
> +    struct cpio_data cd;
>      int idx = opt_mod_idx;
>      int rc;
>  
> @@ -776,7 +777,6 @@ static int __init early_microcode_load(struct boot_info 
> *bi)
>          for ( idx = 0; idx < bi->nr_modules; ++idx )
>          {
>              const struct boot_module *bm = &bi->mods[idx];
> -            struct cpio_data cd;
>  
>              /* Search anything unclaimed or likely to be a CPIO archive. */
>              if ( bm->kind != BOOTMOD_UNKNOWN && bm->kind != BOOTMOD_RAMDISK )
> @@ -844,6 +844,18 @@ static int __init early_microcode_load(struct boot_info 
> *bi)
>                     idx, size);
>              return -ENODEV;
>          }
> +
> +        /*
> +         * If this blob appears to be a CPIO archive, try interpreting it as
> +         * one.  Otherwise treat it as a raw vendor blob.
> +         */
> +        cd = find_cpio_data(ucode_ops.cpio_path, data, size);
> +        if ( cd.data )
> +        {
> +            data = cd.data;
> +            size = cd.size;
> +        }
> +
>          goto found;
>      }

Doesn't microcode_init_cache() then need similar adjustment?

Jan