2023-05-13 22:05:59

by Kirill A. Shutemov

Subject: [PATCHv11 2/9] 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 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 <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
---
drivers/firmware/efi/libstub/x86-stub.c | 26 +++++++++++--------------
1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index a0bfd31358ba..fff81843169c 100644
--- 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;
+ status = efi_get_memory_map(&map, false);
+ if (status != EFI_SUCCESS)
+ return status;

- nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
-
- 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 {
--
2.39.3

2023-05-16 20:17:06

by Tom Lendacky

Subject: Re: [PATCHv11 2/9] efi/x86: Get full memory map in allocate_e820()

On 5/13/23 17:04, Kirill A. Shutemov wrote:
> 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 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 <[email protected]>
> Reviewed-by: Borislav Petkov <[email protected]>
> Acked-by: Ard Biesheuvel <[email protected]>

Reviewed-by: Tom Lendacky <[email protected]>

> ---
> drivers/firmware/efi/libstub/x86-stub.c | 26 +++++++++++--------------
> 1 file changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> index a0bfd31358ba..fff81843169c 100644
> --- 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;
> + status = efi_get_memory_map(&map, false);
> + if (status != EFI_SUCCESS)
> + return status;
>
> - nr_desc = map_size / desc_size + EFI_MMAP_NR_SLACK_SLOTS;
> -
> - 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 {