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How to Enable Secure Boot
8. Set appropriate value of gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize
for security feature relative databases which uses EFI Variable as storage.
Each database stores in a single variable, the maximum variable size is
defined by PCD value of gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize.
Database categories include:
1) PK database: only one entry for public key of PK plus header info.
2) KEK database: multi-entry for public key of KEK plus header info.
3) Authorized signature database: multi-entries for authorized signatures
and one entry for root X509 certificate, plus header info.
4) Forbidden signature database: multi-entries for forbidden signatures,
plus header info.
NOTICE: Typically the size of one X509 certificate is ~2k, which may exceed
the default maximum variable size. Please adjust the value by PCD if
needed.
9. Set a platform policy of image verification by PCDs.
User can customize platform policy of image verification by PCD value
before build a platform. In [PcdsFixedAtBuild] section of SecurityPkg.dec
file, set the PCD value for each type of device accordingly.
For example, if the platform policy is defined as:
1) Trust all images from OptionROM.
2) Validate all images from removable devices and deny execute when security
violation occurs.
3) Validate all images from hard disk and query user to make decision when
security violation occurs.