diff mbox series

[v7,5/9] efi/libstub: Add generic support for parsing mem_encrypt=

Message ID 20240227151907.387873-16-ardb+git@google.com
State New
Headers
Series x86: Confine early 1:1 mapped startup code |

Commit Message

Ard Biesheuvel Feb. 27, 2024, 3:19 p.m. UTC 
  From: Ard Biesheuvel <ardb@kernel.org>

Parse the mem_encrypt= command line parameter from the EFI stub if
CONFIG_ARCH_HAS_MEM_ENCRYPT=y, so that it can be passed to the early
boot code by the arch code in the stub.

This avoids the need for the core kernel to do any string parsing very
early in the boot.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/efi-stub-helper.c | 8 ++++++++
 drivers/firmware/efi/libstub/efistub.h         | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

Comments

Borislav Petkov March 1, 2024, 4:16 p.m. UTC | #1 
On Tue, Feb 27, 2024 at 04:19:13PM +0100, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Parse the mem_encrypt= command line parameter from the EFI stub if
> CONFIG_ARCH_HAS_MEM_ENCRYPT=y, so that it can be passed to the early
> boot code by the arch code in the stub.
> 
> This avoids the need for the core kernel to do any string parsing very
> early in the boot.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  drivers/firmware/efi/libstub/efi-stub-helper.c | 8 ++++++++
>  drivers/firmware/efi/libstub/efistub.h         | 2 +-
>  2 files changed, 9 insertions(+), 1 deletion(-)

Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
diff mbox series

Patch

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index bfa30625f5d0..3dc2f9aaf08d 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -24,6 +24,8 @@  static bool efi_noinitrd;
 static bool efi_nosoftreserve;
 static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA);
 
+int efi_mem_encrypt;
+
 bool __pure __efi_soft_reserve_enabled(void)
 {
 	return !efi_nosoftreserve;
@@ -75,6 +77,12 @@  efi_status_t efi_parse_options(char const *cmdline)
 			efi_noinitrd = true;
 		} else if (IS_ENABLED(CONFIG_X86_64) && !strcmp(param, "no5lvl")) {
 			efi_no5lvl = true;
+		} else if (IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) &&
+			   !strcmp(param, "mem_encrypt") && val) {
+			if (parse_option_str(val, "on"))
+				efi_mem_encrypt = 1;
+			else if (parse_option_str(val, "off"))
+				efi_mem_encrypt = -1;
 		} else if (!strcmp(param, "efi") && val) {
 			efi_nochunk = parse_option_str(val, "nochunk");
 			efi_novamap |= parse_option_str(val, "novamap");
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index c04b82ea40f2..fc18fd649ed7 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -37,8 +37,8 @@  extern bool efi_no5lvl;
 extern bool efi_nochunk;
 extern bool efi_nokaslr;
 extern int efi_loglevel;
+extern int efi_mem_encrypt;
 extern bool efi_novamap;
-
 extern const efi_system_table_t *efi_system_table;
 
 typedef union efi_dxe_services_table efi_dxe_services_table_t;