diff options
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/securityfs-secrets-coco | 51 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-fs-erofs | 5 |
2 files changed, 54 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/securityfs-secrets-coco b/Documentation/ABI/testing/securityfs-secrets-coco new file mode 100644 index 000000000000..f2b6909155f9 --- /dev/null +++ b/Documentation/ABI/testing/securityfs-secrets-coco @@ -0,0 +1,51 @@ +What: security/secrets/coco +Date: February 2022 +Contact: Dov Murik <dovmurik@linux.ibm.com> +Description: + Exposes confidential computing (coco) EFI secrets to + userspace via securityfs. + + EFI can declare memory area used by confidential computing + platforms (such as AMD SEV and SEV-ES) for secret injection by + the Guest Owner during VM's launch. The secrets are encrypted + by the Guest Owner and decrypted inside the trusted enclave, + and therefore are not readable by the untrusted host. + + The efi_secret module exposes the secrets to userspace. Each + secret appears as a file under <securityfs>/secrets/coco, + where the filename is the GUID of the entry in the secrets + table. This module is loaded automatically by the EFI driver + if the EFI secret area is populated. + + Two operations are supported for the files: read and unlink. + Reading the file returns the content of secret entry. + Unlinking the file overwrites the secret data with zeroes and + removes the entry from the filesystem. A secret cannot be read + after it has been unlinked. + + For example, listing the available secrets:: + + # modprobe efi_secret + # ls -l /sys/kernel/security/secrets/coco + -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b + -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6 + -r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2 + -r--r----- 1 root root 0 Jun 28 11:54 e6f5a162-d67f-4750-a67c-5d065f2a9910 + + Reading the secret data by reading a file:: + + # cat /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910 + the-content-of-the-secret-data + + Wiping a secret by unlinking a file:: + + # rm /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910 + # ls -l /sys/kernel/security/secrets/coco + -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b + -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6 + -r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2 + + Note: The binary format of the secrets table injected by the + Guest Owner is described in + drivers/virt/coco/efi_secret/efi_secret.c under "Structure of + the EFI secret area". diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs index 05482374a741..bb4681a01811 100644 --- a/Documentation/ABI/testing/sysfs-fs-erofs +++ b/Documentation/ABI/testing/sysfs-fs-erofs @@ -9,8 +9,9 @@ Description: Shows all enabled kernel features. What: /sys/fs/erofs/<disk>/sync_decompress Date: November 2021 Contact: "Huang Jianan" <huangjianan@oppo.com> -Description: Control strategy of sync decompression +Description: Control strategy of sync decompression: + - 0 (default, auto): enable for readpage, and enable for - readahead on atomic contexts only, + readahead on atomic contexts only. - 1 (force on): enable for readpage and readahead. - 2 (force off): disable for all situations. |