Re: [PATCH v3 2/3] efi: Reserve confidential computing secret area

On 14/10/2021 16:36, Greg KH wrote:

On Thu, Oct 14, 2021 at 01:08:47PM +0000, Dov Murik wrote:

quoted

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 <redacted>
---
 arch/x86/platform/efi/efi.c   |  1 +
 drivers/firmware/efi/Makefile |  2 +-
 drivers/firmware/efi/coco.c   | 41 +++++++++++++++++++++++++++++++++++
 drivers/firmware/efi/efi.c    |  4 ++++
 include/linux/efi.h           |  3 +++
 5 files changed, 50 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,

Shouldn't this depend on CONFIG_EFI_SECRET?

Why build all of this code if that option is not enabled?

Thanks Greg for noticing this.  Fixed in v4 [1] where the code
is guarded with #ifdefs (so it's not built by default).

[1] https://lore.kernel.org/linux-coco/20211020061408.3447533-1-dovmurik@linux.ibm.com/ (local)

-Dov