The measurements for confidential computing has been introduced in the commit 4c76565b6 (efi/tpm: Add EFI_CC_MEASUREMENT_PROTOCOL support). Recently this patch 30708dfe3 (tpm: Disable the tpm verifier if the TPM device is not present) has been introduced to optimize the memory usage when TPM device is not available on the platform. This patch will prevent the tpm module to be loaded on confidential computing platform (for example Intel TDX) where no TPM device is available.
In this patch, we propose to load the tpm module for this use case by generalizing the tpm feature detection in order to cover CC platforms. Basically, do we it by detecting the availability of the EFI protocol EFI_CC_MEASUREMENT_PROTOCOL. Fixes bug : https://savannah.gnu.org/bugs/?65821 --- grub-core/commands/efi/tpm.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/grub-core/commands/efi/tpm.c b/grub-core/commands/efi/tpm.c index f250c30db..386ea3d66 100644 --- a/grub-core/commands/efi/tpm.c +++ b/grub-core/commands/efi/tpm.c @@ -292,6 +292,13 @@ grub_tpm_present (void) { grub_efi_handle_t tpm_handle; grub_efi_uint8_t protocol_version; + grub_efi_cc_protocol_t *cc; + + // if confidential computing measurement protocol is enabled + // we consider TPM is present + cc = grub_efi_locate_protocol (&cc_measurement_guid, NULL); + if (cc != NULL) + return 1; if (!grub_tpm_handle_find (&tpm_handle, &protocol_version)) return 0; -- 2.39.2 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
