1 files changed, 71 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/arm64/hello_el2.c b/tools/testing/selftests/kvm/arm64/hello_el2.c
new file mode 100644
index 000000000000..bbe6862c6ab1
--- /dev/null
+++ b/tools/testing/selftests/kvm/arm64/hello_el2.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * hello_el2 - Basic KVM selftest for VM running at EL2 with E2H=RES1
+ *
+ * Copyright 2025 Google LLC
+ */
+#include "kvm_util.h"
+#include "processor.h"
+#include "test_util.h"
+#include "ucall.h"
+
+#include <asm/sysreg.h>
+
+static void guest_code(void)
+{
+	u64 mmfr0 = read_sysreg_s(SYS_ID_AA64MMFR0_EL1);
+	u64 mmfr1 = read_sysreg_s(SYS_ID_AA64MMFR1_EL1);
+	u64 mmfr4 = read_sysreg_s(SYS_ID_AA64MMFR4_EL1);
+	u8 e2h0 = SYS_FIELD_GET(ID_AA64MMFR4_EL1, E2H0, mmfr4);
+
+	GUEST_ASSERT_EQ(get_current_el(), 2);
+	GUEST_ASSERT(read_sysreg(hcr_el2) & HCR_EL2_E2H);
+	GUEST_ASSERT_EQ(SYS_FIELD_GET(ID_AA64MMFR1_EL1, VH, mmfr1),
+			ID_AA64MMFR1_EL1_VH_IMP);
+
+	/*
+	 * Traps of the complete ID register space are IMPDEF without FEAT_FGT,
+	 * which is really annoying to deal with in KVM describing E2H as RES1.
+	 *
+	 * If the implementation doesn't honor the trap then expect the register
+	 * to return all zeros.
+	 */
+	if (e2h0 == ID_AA64MMFR4_EL1_E2H0_IMP)
+		GUEST_ASSERT_EQ(SYS_FIELD_GET(ID_AA64MMFR0_EL1, FGT, mmfr0),
+				ID_AA64MMFR0_EL1_FGT_NI);
+	else
+		GUEST_ASSERT_EQ(e2h0, ID_AA64MMFR4_EL1_E2H0_NI_NV1);
+
+	GUEST_DONE();
+}
+
+int main(void)
+{
+	struct kvm_vcpu_init init;
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	struct ucall uc;
+
+	TEST_REQUIRE(kvm_check_cap(KVM_CAP_ARM_EL2));
+
+	vm = vm_create(1);
+
+	kvm_get_default_vcpu_target(vm, &init);
+	init.features[0] |= BIT(KVM_ARM_VCPU_HAS_EL2);
+	vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+	kvm_arch_vm_finalize_vcpus(vm);
+
+	vcpu_run(vcpu);
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_DONE:
+		break;
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT(uc);
+		break;
+	default:
+		TEST_FAIL("Unhandled ucall: %ld\n", uc.cmd);
+	}
+
+	kvm_vm_free(vm);
+	return 0;
+}