tree 26c2d1cb2d9741f520d1f5f82c44a60435dc94d8
parent f2a263ed806f8364a107ec67746ba9e231c3114b
author Govindraj Raja <govindraj.raja@arm.com> 1738184470 -0600
committer Varun Wadekar <vwadekar@nvidia.com> 1739883702 +0000

fix(cpus): workaround for accessing ICH_VMCR_EL2

When ICH_VMCR_EL2.VBPR1 is written in Secure state (SCR_EL3.NS==0)
and then subsequently read in Non-secure state (SCR_EL3.NS==1), a
wrong value might be returned. The same issue exists in the opposite way.

Adding workaround in EL3 software that performs context save/restore
on a change of Security state to use a value of SCR_EL3.NS when
accessing ICH_VMCR_EL2 that reflects the Security state that owns the
data being saved or restored. For example, EL3 software should set
SCR_EL3.NS to 1 when saving or restoring the value ICH_VMCR_EL2 for
Non-secure(or Realm) state. EL3 software should clear
SCR_EL3.NS to 0 when saving or restoring the value ICH_VMCR_EL2 for
Secure state.

SDEN documentation:
https://developer.arm.com/documentation/SDEN-1775101/latest/

Change-Id: I9f0403601c6346276e925f02eab55908b009d957
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
(cherry picked from commit 7455cd1721ec3b8671d6a2fae879f86ecfe497fb)