[RFC PATCH v4 23/26] KVM: arm64: Trap disabled features of ID_AA64MMFR1_EL1

[Reiji Watanabe]

Add feature_config_ctrl for LORegions, which is indicated in
ID_AA64MMFR1_EL1, to program configuration register to trap
guest's using the feature when it is not exposed to the guest.

Change trap_loregion() to use vcpu_feature_is_available()
to simplify checking of the feature's availability.

Signed-off-by: Reiji Watanabe <reijiw at google.com>
---
 arch/arm64/kvm/sys_regs.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 229671ec3abd..f8a5ee927ecf 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -365,6 +365,11 @@ static void feature_tracefilt_trap_activate(struct kvm_vcpu *vcpu)
 	feature_trap_activate(vcpu, VCPU_MDCR_EL2, MDCR_EL2_TTRF, 0);
 }
 
+static void feature_lor_trap_activate(struct kvm_vcpu *vcpu)
+{
+	feature_trap_activate(vcpu, VCPU_HCR_EL2, HCR_TLOR, 0);
+}
+
 /* For ID_AA64PFR0_EL1 */
 static struct feature_config_ctrl ftr_ctrl_ras = {
 	.ftr_reg = SYS_ID_AA64PFR0_EL1,
@@ -416,6 +421,15 @@ static struct feature_config_ctrl ftr_ctrl_tracefilt = {
 	.trap_activate = feature_tracefilt_trap_activate,
 };
 
+/* For ID_AA64MMFR1_EL1 */
+static struct feature_config_ctrl ftr_ctrl_lor = {
+	.ftr_reg = SYS_ID_AA64MMFR1_EL1,
+	.ftr_shift = ID_AA64MMFR1_LOR_SHIFT,
+	.ftr_min = 1,
+	.ftr_signed = FTR_UNSIGNED,
+	.trap_activate = feature_lor_trap_activate,
+};
+
 struct id_reg_info {
 	u32	sys_reg;	/* Register ID */
 	u64	sys_val;	/* Sanitized system value */
@@ -947,6 +961,14 @@ static struct id_reg_info id_aa64dfr0_el1_info = {
 	},
 };
 
+static struct id_reg_info id_aa64mmfr1_el1_info = {
+	.sys_reg = SYS_ID_AA64MMFR1_EL1,
+	.trap_features = &(const struct feature_config_ctrl *[]) {
+		&ftr_ctrl_lor,
+		NULL,
+	},
+};
+
 static struct id_reg_info id_dfr0_el1_info = {
 	.sys_reg = SYS_ID_DFR0_EL1,
 	.init = init_id_dfr0_el1_info,
@@ -976,6 +998,7 @@ static struct id_reg_info *id_reg_info_table[KVM_ARM_ID_REG_MAX_NUM] = {
 	[IDREG_IDX(SYS_ID_AA64ISAR0_EL1)] = &id_aa64isar0_el1_info,
 	[IDREG_IDX(SYS_ID_AA64ISAR1_EL1)] = &id_aa64isar1_el1_info,
 	[IDREG_IDX(SYS_ID_AA64MMFR0_EL1)] = &id_aa64mmfr0_el1_info,
+	[IDREG_IDX(SYS_ID_AA64MMFR1_EL1)] = &id_aa64mmfr1_el1_info,
 };
 
 static int validate_id_reg(struct kvm_vcpu *vcpu, u32 id, u64 val)
@@ -1050,10 +1073,9 @@ static bool trap_loregion(struct kvm_vcpu *vcpu,
 			  struct sys_reg_params *p,
 			  const struct sys_reg_desc *r)
 {
-	u64 val = __read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1);
 	u32 sr = reg_to_encoding(r);
 
-	if (!(val & (0xfUL << ID_AA64MMFR1_LOR_SHIFT))) {
+	if (!vcpu_feature_is_available(vcpu, &ftr_ctrl_lor)) {
 		kvm_inject_undefined(vcpu);
 		return false;
 	}
-- 
2.34.1.448.ga2b2bfdf31-goog