linux-kernel - [tip: x86/cc] efi/x86: Get full memory map in allocate

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Date:   Tue, 06 Jun 2023 19:42:40 -0000
From:   "tip-bot2 for Kirill A. Shutemov" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        "Borislav Petkov (AMD)" <bp@...en8.de>,
        Borislav Petkov <bp@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>,
        Ard Biesheuvel <ardb@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/cc] efi/x86: Get full memory map in allocate_e820()

The following commit has been merged into the x86/cc branch of tip:

Commit-ID:     2e9f46ee1599be8a50a5366eb3ef4a4b5acff0b7
Gitweb:        https://git.kernel.org/tip/2e9f46ee1599be8a50a5366eb3ef4a4b5acff0b7
Author:        Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
AuthorDate:    Tue, 06 Jun 2023 17:26:30 +03:00
Committer:     Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Tue, 06 Jun 2023 16:45:14 +02:00

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@...ux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@....com>
Acked-by: Ard Biesheuvel <ardb@...nel.org>
Link: https://lore.kernel.org/r/20230606142637.5171-3-kirill.shutemov@linux.intel.com
---
 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 a0bfd31..cd77a7a 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;
-
-	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 {