Re: [PATCH] EFI: map allocation size must be set to zero

[Ian Campbell <ian.campbell@citrix.com>]

On Thu, 2015-06-11 at 12:35 +0100, Jan Beulich wrote:
> Commit 8a753b3f1c ("efi: fix allocation problems if ExitBootServices()
> fails") replaced the use of a static (and hence zero-initialized)
> variable by an automatic (and hence uninitialized) one.
> 
> Also drop the variable introduced by that commit in favor of re-using
> another available and suitable one.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Acked-by: Ian Campbell <ian.campbell@citrix.com>

> 
> --- a/xen/common/efi/boot.c
> +++ b/xen/common/efi/boot.c
> @@ -704,7 +704,7 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SY
>      EFI_STATUS status;
>      unsigned int i, argc;
>      CHAR16 **argv, *file_name, *cfg_file_name = NULL, *options = NULL;
> -    UINTN map_alloc_size, map_key, info_size, gop_mode = ~0;
> +    UINTN map_key, info_size, gop_mode = ~0;
>      EFI_HANDLE *handles = NULL;
>      EFI_SHIM_LOCK_PROTOCOL *shim_lock;
>      EFI_GRAPHICS_OUTPUT_PROTOCOL *gop = NULL;
> @@ -1061,16 +1061,17 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SY
>              efi_arch_video_init(gop, info_size, mode_info);
>      }
>  
> -    efi_bs->GetMemoryMap(&map_alloc_size, NULL, &map_key,
> +    info_size = 0;
> +    efi_bs->GetMemoryMap(&info_size, NULL, &map_key,
>                           &efi_mdesc_size, &mdesc_ver);
> -    map_alloc_size += 8 * efi_mdesc_size;
> -    efi_memmap = efi_arch_allocate_mmap_buffer(map_alloc_size);
> +    info_size += 8 * efi_mdesc_size;
> +    efi_memmap = efi_arch_allocate_mmap_buffer(info_size);
>      if ( !efi_memmap )
>          blexit(L"Unable to allocate memory for EFI memory map");
>  
>      for ( retry = 0; ; retry = 1 )
>      {
> -        efi_memmap_size = map_alloc_size;
> +        efi_memmap_size = info_size;
>          status = efi_bs->GetMemoryMap(&efi_memmap_size, efi_memmap, &map_key,
>                                        &efi_mdesc_size, &mdesc_ver);
>          if ( EFI_ERROR(status) )
> 
> 
> 
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