UefiCpuPkg/CommonFeature: Always set FEATURE_CONTROL.Lock
authorRuiyu Ni <ruiyu.ni@intel.com>
Tue, 13 Nov 2018 07:34:33 +0000 (15:34 +0800)
committerRuiyu Ni <ruiyu.ni@intel.com>
Wed, 14 Nov 2018 03:02:48 +0000 (11:02 +0800)
commit85588389222a3636baf0f9ed8227f2434af4c3f9
tree5a948f9bad2ab4fc7c74bc7ec47f6757aa06a106
parentbd224a5dad4d32f5224f5e8ae998b70e4621dcd3
UefiCpuPkg/CommonFeature: Always set FEATURE_CONTROL.Lock

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1305

The patch reverts commit 1ed6498c4a0210204bf4b95cc0c0cd6623ad6a0b
* UefiCpuPkg/CommonFeature: Skip locking when the feature is disabled

FEATURE_CONTROL.Lock bit is controlled by feature
CPU_FEATURE_LOCK_FEATURE_CONTROL_REGISTER. The commit 1ed649 fixes
a bug that when the feature is disabled, the Lock bit is cleared.
But it's a security hole if the bit is cleared when booting OS.
We can argue that platform needs to make sure the value
of PcdCpuFeaturesUserConfiguration should be set properly to make
sure feature CPU_FEATURE_LOCK_FEATURE_CONTROL_REGISTER is enabled.

But it's better to guarantee this in the generic core code.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
UefiCpuPkg/Library/CpuCommonFeaturesLib/FeatureControl.c