Add feature_config_ctrl for PTRAUTH, which is indicated in
ID_AA64ISAR1_EL1, to program configuration register to trap
guest's using the feature when it is not exposed to the guest.
Signed-off-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f3661881cbed..881e8879a48b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -284,6 +284,30 @@ static bool trap_raz_wi(struct kvm_vcpu *vcpu,
(cpuid_feature_extract_unsigned_field(val, ID_AA64ISAR1_GPI_SHIFT) >= \
ID_AA64ISAR1_GPI_IMP_DEF)
+/*
+ * Return true if ptrauth needs to be trapped.
+ * (i.e. if ptrauth is supported on the host but not exposed to the guest)
+ */
+static bool vcpu_need_trap_ptrauth(struct kvm_vcpu *vcpu)
+{
+ u64 val;
+ bool generic, address;
+
+ if (!system_has_full_ptr_auth())
+ /* The feature is not supported. */
+ return false;
+
+ val = read_id_reg_with_encoding(vcpu, SYS_ID_AA64ISAR1_EL1);
+ generic = aa64isar1_has_gpi(val) || aa64isar1_has_gpa(val);
+ address = aa64isar1_has_api(val) || aa64isar1_has_apa(val);
+ if (generic && address)
+ /* The feature is available. */
+ return false;
+
+ /* The feature is supported but hidden. */
+ return true;
+}
+
/*
* Feature information to program configuration register to trap or disable
* guest's using a feature when the feature is not exposed to the guest.
@@ -379,6 +403,11 @@ static void feature_lor_trap_activate(struct kvm_vcpu *vcpu)
feature_trap_activate(vcpu, VCPU_HCR_EL2, HCR_TLOR, 0);
}
+static void feature_ptrauth_trap_activate(struct kvm_vcpu *vcpu)
+{
+ feature_trap_activate(vcpu, VCPU_HCR_EL2, 0, HCR_API | HCR_APK);
+}
+
/* For ID_AA64PFR0_EL1 */
static struct feature_config_ctrl ftr_ctrl_ras = {
.ftr_reg = SYS_ID_AA64PFR0_EL1,
@@ -447,6 +476,12 @@ static struct feature_config_ctrl ftr_ctrl_lor = {
.trap_activate = feature_lor_trap_activate,
};
+/* For SYS_ID_AA64ISAR1_EL1 */
+static struct feature_config_ctrl ftr_ctrl_ptrauth = {
+ .ftr_need_trap = vcpu_need_trap_ptrauth,
+ .trap_activate = feature_ptrauth_trap_activate,
+};
+
/* id_reg_desc flags field values */
#define ID_DESC_REG_UNALLOC (1UL << 0)
#define ID_DESC_REG_HIDDEN (1UL << 1)
@@ -3782,6 +3817,10 @@ static struct id_reg_desc id_aa64isar1_el1_desc = {
.init = init_id_aa64isar1_el1_desc,
.validate = validate_id_aa64isar1_el1,
.vcpu_mask = vcpu_mask_id_aa64isar1_el1,
+ .trap_features = &(const struct feature_config_ctrl *[]) {
+ &ftr_ctrl_ptrauth,
+ NULL,
+ },
};
static struct id_reg_desc id_aa64mmfr0_el1_desc = {
--
2.35.1.723.g4982287a31-goog
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