When efi-stub copies an EFI-provided confidential computing (coco) secret area, reserve that memory block for future use within the kernel. Signed-off-by: Dov Murik <dovmurik@xxxxxxxxxxxxx> --- arch/x86/platform/efi/efi.c | 1 + drivers/firmware/efi/Makefile | 2 +- drivers/firmware/efi/coco.c | 41 +++++++++++++++++++++++++++++++++++ drivers/firmware/efi/efi.c | 3 +++ include/linux/efi.h | 3 +++ 5 files changed, 49 insertions(+), 1 deletion(-) create mode 100644 drivers/firmware/efi/coco.c diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 147c30a81f15..35e082e5f603 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -93,6 +93,7 @@ static const unsigned long * const efi_tables[] = { #ifdef CONFIG_LOAD_UEFI_KEYS &efi.mokvar_table, #endif + &efi.coco_secret, }; u64 efi_setup; /* efi setup_data physical address */ diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index c02ff25dd477..bfd35294703e 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -12,7 +12,7 @@ KASAN_SANITIZE_runtime-wrappers.o := n obj-$(CONFIG_ACPI_BGRT) += efi-bgrt.o obj-$(CONFIG_EFI) += efi.o vars.o reboot.o memattr.o tpm.o -obj-$(CONFIG_EFI) += memmap.o +obj-$(CONFIG_EFI) += memmap.o coco.o ifneq ($(CONFIG_EFI_CAPSULE_LOADER),) obj-$(CONFIG_EFI) += capsule.o endif diff --git a/drivers/firmware/efi/coco.c b/drivers/firmware/efi/coco.c new file mode 100644 index 000000000000..42f477d6188c --- /dev/null +++ b/drivers/firmware/efi/coco.c @@ -0,0 +1,41 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Confidential computing (coco) secret area handling + * + * Copyright (C) 2021 IBM Corporation + * Author: Dov Murik <dovmurik@xxxxxxxxxxxxx> + */ + +#define pr_fmt(fmt) "efi: " fmt + +#include <linux/efi.h> +#include <linux/init.h> +#include <linux/memblock.h> +#include <asm/early_ioremap.h> + +/* + * Reserve the confidential computing secret area memory + */ +int __init efi_coco_secret_area_reserve(void) +{ + struct linux_efi_coco_secret_area *secret_area; + unsigned long secret_area_size; + + if (efi.coco_secret == EFI_INVALID_TABLE_ADDR) + return 0; + + secret_area = early_memremap(efi.coco_secret, sizeof(*secret_area)); + if (!secret_area) { + pr_err("Failed to map confidential computing secret area\n"); + efi.coco_secret = EFI_INVALID_TABLE_ADDR; + return -ENOMEM; + } + + secret_area_size = sizeof(*secret_area) + secret_area->size; + memblock_reserve(efi.coco_secret, secret_area_size); + + pr_info("Reserved memory of EFI-provided confidential computing secret area"); + + early_memunmap(secret_area, sizeof(*secret_area)); + return 0; +} diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 847f33ffc4ae..07e17ad225a6 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -526,6 +526,7 @@ static const efi_config_table_type_t common_tables[] __initconst = { #ifdef CONFIG_LOAD_UEFI_KEYS {LINUX_EFI_MOK_VARIABLE_TABLE_GUID, &efi.mokvar_table, "MOKvar" }, #endif + {LINUX_EFI_COCO_SECRET_AREA_GUID, &efi.coco_secret, "CocoSecret" }, {}, }; @@ -613,6 +614,8 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables, efi_tpm_eventlog_init(); + efi_coco_secret_area_reserve(); + if (mem_reserve != EFI_INVALID_TABLE_ADDR) { unsigned long prsv = mem_reserve; diff --git a/include/linux/efi.h b/include/linux/efi.h index 9021dd521302..e86600af5dfd 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -550,6 +550,7 @@ extern struct efi { unsigned long tpm_log; /* TPM2 Event Log table */ unsigned long tpm_final_log; /* TPM2 Final Events Log table */ unsigned long mokvar_table; /* MOK variable config table */ + unsigned long coco_secret; /* Confidential computing secret table */ efi_get_time_t *get_time; efi_set_time_t *set_time; @@ -1189,6 +1190,8 @@ extern int efi_tpm_final_log_size; extern unsigned long rci2_table_phys; +extern int efi_coco_secret_area_reserve(void); + /* * efi_runtime_service() function identifiers. * "NONE" is used by efi_recover_from_page_fault() to check if the page -- 2.25.1