KVM: arm64: Make ID_AA64MMFR1_EL1.{HCX, TWED} writable from userspace

Allow userspace to downgrade {HCX, TWED} in ID_AA64MMFR1_EL1. Userspace can
only change the value from high to low.

Signed-off-by: Jinqian Yang <yangjinqian1@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Jinqian Yang

arch/arm64/kvm/sys_regs.c

@@ -3152,8 +3152,6 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 				      ~(ID_AA64MMFR0_EL1_RES0 |
 					ID_AA64MMFR0_EL1_ASIDBITS)),
 	ID_WRITABLE(ID_AA64MMFR1_EL1, ~(ID_AA64MMFR1_EL1_RES0 |
-					ID_AA64MMFR1_EL1_HCX |
-					ID_AA64MMFR1_EL1_TWED |
 					ID_AA64MMFR1_EL1_XNX |
 					ID_AA64MMFR1_EL1_VH |
 					ID_AA64MMFR1_EL1_VMIDBits)),