hello_el2.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * hello_el2 - Basic KVM selftest for VM running at EL2 with E2H=RES1
 4 *
 5 * Copyright 2025 Google LLC
 6 */
 7#include "kvm_util.h"
 8#include "processor.h"
 9#include "test_util.h"
10#include "ucall.h"
11
12#include <asm/sysreg.h>
13
14static void guest_code(void)
15{
16	u64 mmfr0 = read_sysreg_s(SYS_ID_AA64MMFR0_EL1);
17	u64 mmfr1 = read_sysreg_s(SYS_ID_AA64MMFR1_EL1);
18	u64 mmfr4 = read_sysreg_s(SYS_ID_AA64MMFR4_EL1);
19	u8 e2h0 = SYS_FIELD_GET(ID_AA64MMFR4_EL1, E2H0, mmfr4);
20
21	GUEST_ASSERT_EQ(get_current_el(), 2);
22	GUEST_ASSERT(read_sysreg(hcr_el2) & HCR_EL2_E2H);
23	GUEST_ASSERT_EQ(SYS_FIELD_GET(ID_AA64MMFR1_EL1, VH, mmfr1),
24			ID_AA64MMFR1_EL1_VH_IMP);
25
26	/*
27	 * Traps of the complete ID register space are IMPDEF without FEAT_FGT,
28	 * which is really annoying to deal with in KVM describing E2H as RES1.
29	 *
30	 * If the implementation doesn't honor the trap then expect the register
31	 * to return all zeros.
32	 */
33	if (e2h0 == ID_AA64MMFR4_EL1_E2H0_IMP)
34		GUEST_ASSERT_EQ(SYS_FIELD_GET(ID_AA64MMFR0_EL1, FGT, mmfr0),
35				ID_AA64MMFR0_EL1_FGT_NI);
36	else
37		GUEST_ASSERT_EQ(e2h0, ID_AA64MMFR4_EL1_E2H0_NI_NV1);
38
39	GUEST_DONE();
40}
41
42int main(void)
43{
44	struct kvm_vcpu_init init;
45	struct kvm_vcpu *vcpu;
46	struct kvm_vm *vm;
47	struct ucall uc;
48
49	TEST_REQUIRE(kvm_check_cap(KVM_CAP_ARM_EL2));
50
51	vm = vm_create(1);
52
53	kvm_get_default_vcpu_target(vm, &init);
54	init.features[0] |= BIT(KVM_ARM_VCPU_HAS_EL2);
55	vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
56	kvm_arch_vm_finalize_vcpus(vm);
57
58	vcpu_run(vcpu);
59	switch (get_ucall(vcpu, &uc)) {
60	case UCALL_DONE:
61		break;
62	case UCALL_ABORT:
63		REPORT_GUEST_ASSERT(uc);
64		break;
65	default:
66		TEST_FAIL("Unhandled ucall: %ld\n", uc.cmd);
67	}
68
69	kvm_vm_free(vm);
70	return 0;
71}