[PATCH] efi_loader: consider no-map property of reserved memory

[Atish Patra]

On Thu, Aug 27, 2020 at 9:16 AM Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>
> If a reserved memory node in the device tree has the property no-map,
> remove it from the UEFI memory map provided by GetMemoryMap().
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>  cmd/bootefi.c               | 34 ++++++++++++++++++++++++++++------
>  include/efi.h               |  3 +++
>  lib/efi_loader/efi_memory.c |  7 +++++--
>  3 files changed, 36 insertions(+), 8 deletions(-)
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 40d5ef2b3a..f173105251 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -135,12 +135,29 @@ done:
>         return ret;
>  }
>
> -static void efi_reserve_memory(u64 addr, u64 size)
> +/**
> + * efi_reserve_memory() - add reserved memory to memory map
> + *
> + * @addr:      start address of the reserved memory range
> + * @size:      size of the reserved memory range
> + * @nomap:     indicates that the memory range shall be hidden from the memory
> + *             map
> + */
> +static void efi_reserve_memory(u64 addr, u64 size, bool nomap)
>  {
> +       int type;
> +       efi_uintn_t ret;
> +
>         /* Convert from sandbox address space. */
>         addr = (uintptr_t)map_sysmem(addr, 0);
> -       if (efi_add_memory_map(addr, size,
> -                              EFI_RESERVED_MEMORY_TYPE) != EFI_SUCCESS)
> +
> +       if (nomap)
> +               type = EFI_NO_MAP_MEMORY;
> +       else
> +               type = EFI_RESERVED_MEMORY_TYPE;
> +
> +       ret = efi_add_memory_map(addr, size, type);
> +       if (ret != EFI_SUCCESS)
>                 log_err("Reserved memory mapping failed addr %llx size %llx\n",
>                         addr, size);
>  }
> @@ -166,7 +183,7 @@ static void efi_carve_out_dt_rsv(void *fdt)
>         for (i = 0; i < nr_rsv; i++) {
>                 if (fdt_get_mem_rsv(fdt, i, &addr, &size) != 0)
>                         continue;
> -               efi_reserve_memory(addr, size);
> +               efi_reserve_memory(addr, size, false);
>         }
>
>         /* process reserved-memory */
> @@ -186,8 +203,13 @@ static void efi_carve_out_dt_rsv(void *fdt)
>                          * a size instead of a reg property.
>                          */
>                         if (fdt_addr != FDT_ADDR_T_NONE &&
> -                           fdtdec_get_is_enabled(fdt, subnode))
> -                               efi_reserve_memory(fdt_addr, fdt_size);
> +                           fdtdec_get_is_enabled(fdt, subnode)) {
> +                               bool nomap;
> +
> +                               nomap = !!fdt_getprop(fdt, subnode, "no-map",
> +                                                     NULL);
> +                               efi_reserve_memory(fdt_addr, fdt_size, nomap);
> +                       }
>                         subnode = fdt_next_subnode(fdt, subnode);
>                 }
>         }
> diff --git a/include/efi.h b/include/efi.h
> index f986aad877..50190021ef 100644
> --- a/include/efi.h
> +++ b/include/efi.h
> @@ -181,6 +181,9 @@ enum efi_mem_type {
>
>         EFI_MAX_MEMORY_TYPE,
>         EFI_TABLE_END,  /* For efi_build_mem_table() */
> +
> +       /* Memory that shall not be mapped */
> +       EFI_NO_MAP_MEMORY,

Should it be named as EFI_NO_MAP_RSVD_MEMORY to avoid ambiguity ?

>  };
>
>  /* Attribute values */
> diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
> index 7be756e370..d156b9533c 100644
> --- a/lib/efi_loader/efi_memory.c
> +++ b/lib/efi_loader/efi_memory.c
> @@ -251,7 +251,7 @@ static efi_status_t efi_add_memory_map_pg(u64 start, u64 pages,
>         EFI_PRINT("%s: 0x%llx 0x%llx %d %s\n", __func__,
>                   start, pages, memory_type, overlap_only_ram ? "yes" : "no");
>
> -       if (memory_type >= EFI_MAX_MEMORY_TYPE)
> +       if (memory_type >= EFI_MAX_MEMORY_TYPE && memory_type != EFI_NO_MAP_MEMORY)
>                 return EFI_INVALID_PARAMETER;
>
>         if (!pages)
> @@ -327,7 +327,10 @@ static efi_status_t efi_add_memory_map_pg(u64 start, u64 pages,
>         }
>
>         /* Add our new map */
> -        list_add_tail(&newlist->link, &efi_mem);
> +       if (memory_type == EFI_NO_MAP_MEMORY)
> +               free(newlist);
> +       else
> +               list_add_tail(&newlist->link, &efi_mem);
>
>         /* And make sure memory is listed in descending order */
>         efi_mem_sort();
> --
> 2.28.0
>


-- 
Regards,
Atish