2022-06-14 12:04:08

by Kirill A. Shutemov

Subject: [PATCHv7 04/14] efi/x86: Get full memory map in allocate_e820()

Currently allocate_e820() 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.

This is preparation for the next patch that implements handling of
unaccepted memory in EFI stub.

Signed-off-by: Kirill A. Shutemov <[email protected]>
---
drivers/firmware/efi/libstub/x86-stub.c | 28 +++++++++++--------------
1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
index 05ae8bcc9d67..504955368934 100644
--- a/drivers/firmware/efi/libstub/x86-stub.c
+++ b/drivers/firmware/efi/libstub/x86-stub.c
@@ -672,31 +672,27 @@ static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
}

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;
}

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

struct exit_boot_struct {
@@ -745,7 +741,7 @@ static efi_status_t exit_boot(struct boot_params *boot_params, void *handle)
priv.boot_params = boot_params;
priv.efi = &boot_params->efi_info;

- status = allocate_e820(boot_params, &e820ext, &e820ext_size);
+ status = allocate_e820(boot_params, &map, &e820ext, &e820ext_size);
if (status != EFI_SUCCESS)
return status;

--
2.35.1

2022-07-25 13:06:32

by Borislav Petkov

Subject: Re: [PATCHv7 04/14] efi/x86: Get full memory map in allocate_e820()

On Tue, Jun 14, 2022 at 03:02:21PM +0300, Kirill A. Shutemov wrote:
> Currently allocate_e820() only interested in the size of map and size of
^
is


> 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.
>
> This is preparation for the next patch that implements handling of
> unaccepted memory in EFI stub.

As already pointed out, the concept of "next patch" is ambiguous in git.
Just drop the whole sentence.

> Signed-off-by: Kirill A. Shutemov <[email protected]>
> ---
> drivers/firmware/efi/libstub/x86-stub.c | 28 +++++++++++--------------
> 1 file changed, 12 insertions(+), 16 deletions(-)

With the above addressed:

Reviewed-by: Borislav Petkov <[email protected]>

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette