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

Commit Message

Kirill A. Shutemov June 14, 2022, 12:02 p.m. UTC

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 <[e-mail]>
---
 drivers/firmware/efi/libstub/x86-stub.c | 28 +++++++++++--------------
 1 file changed, 12 insertions(+), 16 deletions(-)

Comments

Borislav Petkov July 25, 2022, 1:02 p.m. UTC | #1

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 <[e-mail]>
> ---
>  drivers/firmware/efi/libstub/x86-stub.c | 28 +++++++++++--------------
>  1 file changed, 12 insertions(+), 16 deletions(-)

With the above addressed:

Reviewed-by: Borislav Petkov <[e-mail]>

Thx.

Patch

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;