Re: [PATCHv5 03/12] efi/x86: Get full memory map in allocate_e820()

Borislav Petkov
2022-04-27T20:26:33Z

On Mon, Apr 25, 2022 at 06:39:25AM +0300, Kirill A. Shutemov wrote:
> static efi_status_t allocate_e820(struct boot_params *params,
> + struct efi_boot_memmap *map,
> struct setup_data **e820ext,
> u32 *e820ext_size)
> {
> - unsigned long map_size, desc_size, map_key;
> 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);
> + 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;
> + goto out;

Still silly, that label is useless then. Pasting the whole, simplified
function below.

It looks like it all boils down to propagating the retval up the chain...

static efi_status_t allocate_e820(struct boot_params *params,
struct efi_boot_memmap *map,
struct setup_data **e820ext,
u32 *e820ext_size)
{
efi_status_t status;
__u32 nr_desc;

status = efi_get_memory_map(map);
if (status != EFI_SUCCESS)
return status;

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);
}

efi_bs_call(free_pool, *map->map);
return status;
}

--
Regards/Gruss,
Boris.