efi/x86: Get full memory map in allocate_e820()

Currently allocate_e820() is only interested in the size of map and size
of memory descriptor to determine how many e820 entries the kernel
needs.

UEFI Specification version 2.9 introduces a new memory type --
unaccepted memory. To track unaccepted memory, the kernel needs to
allocate a bitmap. The size of the bitmap is dependent on the maximum
physical address present in the system. A full memory map is required to
find the maximum address.

Modify allocate_e820() to get a full memory map.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-3-kirill.shutemov@linux.intel.com

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index a0bfd31..cd77a7a 100644 (file)
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -681,28 +681,24 @@ static efi_status_t allocate_e820(struct boot_params *params,
                                  struct setup_data **e820ext,
                                  u32 *e820ext_size)
 {
-       unsigned long map_size, desc_size, map_key;
+       struct efi_boot_memmap *map;
        efi_status_t status;
-       __u32 nr_desc, desc_version;
+       __u32 nr_desc;
 
-       /* Only need the size of the mem map and size of each mem descriptor */
-       map_size = 0;
-       status = efi_bs_call(get_memory_map, &map_size, NULL, &map_key,
-                            &desc_size, &desc_version);
-       if (status != EFI_BUFFER_TOO_SMALL)
-               return (status != EFI_SUCCESS) ? status : EFI_UNSUPPORTED;
-
-       nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
+       status = efi_get_memory_map(&map, false);
+       if (status != EFI_SUCCESS)
+               return status;
 
-       if (nr_desc > ARRAY_SIZE(params->e820_table)) {
-               u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table);
+       nr_desc = map->map_size / map->desc_size;
+       if (nr_desc > ARRAY_SIZE(params->e820_table) - EFI_MMAP_NR_SLACK_SLOTS) {
+               u32 nr_e820ext = nr_desc - ARRAY_SIZE(params->e820_table) +
+                                EFI_MMAP_NR_SLACK_SLOTS;
 
                status = alloc_e820ext(nr_e820ext, e820ext, e820ext_size);
-               if (status != EFI_SUCCESS)
-                       return status;
        }
 
-       return EFI_SUCCESS;
+       efi_bs_call(free_pool, map);
+       return status;
 }
 
 struct exit_boot_struct {