--- v5
+++ v3
@@ -9,17 +9,15 @@
Sev Secret area using a configuration table" [1]), but the secrets were
not available in the guest kernel.
-The patch series keeps the address of the EFI-provided memory for
-injected secrets, and optionally exposes the secrets to userspace via
+The patch series copies the secrets from the EFI-provided memory to
+kernel reserved memory, and optionally exposes them to userspace via
securityfs using a new efi_secret kernel module.
-The first patch in EFI keeps the address of the secret area as passed in
-the EFI configuration table. The second patch is a quirk fix for older
-firmwares didn't mark the secrets page as EFI_RESERVED_TYPE. The third
-patch introduces the new efi_secret module that exposes the content of
-the secret entries as securityfs files, and allows clearing out secrets
-with a file unlink interface. The last patch documents the data flow of
-confidential computing secret injection.
+The first patch in efi/libstub copies the secret area from the EFI
+memory to specially allocated memory; the second patch reserves that
+memory block; and the third patch introduces the new efi_secret module
+that exposes the content of the secret entries as securityfs files, and
+allows clearing out secrets with a file unlink interface.
As a usage example, consider a guest performing computations on
encrypted files. The Guest Owner provides the decryption key (= secret)
@@ -38,9 +36,6 @@
therefore might be usable (perhaps with minor changes) for any
confidential computing hardware that can publish the secret area via the
standard EFI config table entry.
-
-To enable this functionality, set CONFIG_EFI_SECRET=m when building the
-guest kernel.
Here is a simple example for usage of the efi_secret module in a guest
to which an EFI secret area with 4 secrets was injected during launch:
@@ -75,30 +70,6 @@
---
-v5 changes:
- - Simplify EFI code: instead of copying the secret area, the firmware
- marks the secret area as EFI_RESERVED_TYPE, and then the uefi_init()
- code just keeps the pointer as it appears in the EFI configuration
- table. The use of reserved pages is similar to the AMD SEV-SNP
- patches for handling SNP-Secrets and SNP-CPUID pages.
- - In order to handle OVMF releases out there which mark the
- confidential computing secrets page as EFI_BOOT_SERVICES_DATA, add
- efi/libstub code that detects this and fixes the E820 map to reserve
- this page.
- - In the efi_secret module code, map the secrets page using
- ioremap_encrypted (again, similar to the AMD SEV-SNP guest patches
- for accessing SNP-Secrets and SNP-CPUID pages).
- - Add documentation in Documentation/security/coco/efi_secret.
-
-v4: https://lore.kernel.org/linux-coco/20211020061408.3447533-1-dovmurik@linux.ibm.com/
-v4 changes:
- - Guard all the new EFI and efi-stub code (patches 1+2) with #ifdef
- CONFIG_EFI_COCO_SECRET (thanks Greg KH). Selecting
- CONFIG_EFI_SECRET=m (patch 3) will enable the EFI parts as well.
- - Guard call to clflush_cache_range() with #ifdef CONFIG_X86
- (Reported-by: kernel test robot <lkp@intel.com>)
-
-v3: https://lore.kernel.org/linux-coco/20211014130848.592611-1-dovmurik@linux.ibm.com/
v3 changes:
- Rename the module to efi_secret
- Remove the exporting of clean_cache_range
@@ -118,38 +89,37 @@
RFC: https://lore.kernel.org/linux-coco/20210628183431.953934-1-dovmurik@linux.ibm.com/
-
-
-Dov Murik (4):
- efi: Save location of EFI confidential computing area
- efi/libstub: Reserve confidential computing secret area
+Dov Murik (3):
+ efi/libstub: Copy confidential computing secret area
+ efi: Reserve confidential computing secret area
virt: Add efi_secret module to expose confidential computing secrets
- docs: security: Add coco/efi_secret documentation
.../ABI/testing/securityfs-coco-efi_secret | 50 +++
- Documentation/security/coco/efi_secret.rst | 103 ++++++
- Documentation/security/coco/index.rst | 9 +
- Documentation/security/index.rst | 1 +
- arch/x86/platform/efi/efi.c | 3 +
- drivers/firmware/efi/Kconfig | 16 +
- drivers/firmware/efi/efi.c | 6 +
- drivers/firmware/efi/libstub/x86-stub.c | 28 ++
+ arch/x86/platform/efi/efi.c | 1 +
+ drivers/firmware/efi/Makefile | 2 +-
+ drivers/firmware/efi/coco.c | 41 +++
+ drivers/firmware/efi/efi.c | 4 +
+ drivers/firmware/efi/libstub/Makefile | 2 +-
+ drivers/firmware/efi/libstub/coco.c | 68 ++++
+ drivers/firmware/efi/libstub/efi-stub.c | 2 +
+ drivers/firmware/efi/libstub/efistub.h | 2 +
+ drivers/firmware/efi/libstub/x86-stub.c | 2 +
drivers/virt/Kconfig | 3 +
drivers/virt/Makefile | 1 +
- drivers/virt/coco/efi_secret/Kconfig | 11 +
+ drivers/virt/coco/efi_secret/Kconfig | 10 +
drivers/virt/coco/efi_secret/Makefile | 2 +
- drivers/virt/coco/efi_secret/efi_secret.c | 341 ++++++++++++++++++
- include/linux/efi.h | 7 +
- 14 files changed, 581 insertions(+)
+ drivers/virt/coco/efi_secret/efi_secret.c | 324 ++++++++++++++++++
+ include/linux/efi.h | 9 +
+ 16 files changed, 521 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/securityfs-coco-efi_secret
- create mode 100644 Documentation/security/coco/efi_secret.rst
- create mode 100644 Documentation/security/coco/index.rst
+ create mode 100644 drivers/firmware/efi/coco.c
+ create mode 100644 drivers/firmware/efi/libstub/coco.c
create mode 100644 drivers/virt/coco/efi_secret/Kconfig
create mode 100644 drivers/virt/coco/efi_secret/Makefile
create mode 100644 drivers/virt/coco/efi_secret/efi_secret.c
-base-commit: 42eb8fdac2fc5d62392dcfcf0253753e821a97b0
+base-commit: 60a9483534ed0d99090a2ee1d4bb0b8179195f51
--
2.25.1