[PATCH v2 1/3] KVM: arm64: Make ID_AA64MMFR1_EL1.HCX writable from userspace

[Jinqian Yang]

Allow userspace to downgrade HCX in ID_AA64MMFR1_EL1. Userspace can
only change this value from high to low.

Signed-off-by: Jinqian Yang <yangjinqian1 at huawei.com>
---
 arch/arm64/kvm/sys_regs.c                       | 1 -
 tools/testing/selftests/kvm/arm64/set_id_regs.c | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 82ffb3b3b3cf..f2267db1c44c 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -3002,7 +3002,6 @@ 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 |
diff --git a/tools/testing/selftests/kvm/arm64/set_id_regs.c b/tools/testing/selftests/kvm/arm64/set_id_regs.c
index d3bf9204409c..a744dee30cd2 100644
--- a/tools/testing/selftests/kvm/arm64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/arm64/set_id_regs.c
@@ -165,6 +165,7 @@ static const struct reg_ftr_bits ftr_id_aa64mmfr0_el1[] = {
 static const struct reg_ftr_bits ftr_id_aa64mmfr1_el1[] = {
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, TIDCP1, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, AFP, 0),
+	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, HCX, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, ETS, 0),
 	REG_FTR_BITS(FTR_HIGHER_SAFE, ID_AA64MMFR1_EL1, SpecSEI, 0),
 	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, PAN, 0),
-- 
2.33.0