tools/testing/selftests/kvm/x86/svm_nested_vmcb12_gpa.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2026, Google LLC.
 */
#include "kvm_util.h"
#include "vmx.h"
#include "svm_util.h"
#include "kselftest.h"
#include "kvm_test_harness.h"
#include "test_util.h"

#define SYNC_GP 101
#define SYNC_L2_STARTED 102

static void guest_gp_handler(struct ex_regs *regs)
{
	GUEST_SYNC(SYNC_GP);
}

static void l2_code(void)
{
	GUEST_SYNC(SYNC_L2_STARTED);
	vmcall();
}

static void l1_vmrun(struct svm_test_data *svm, gpa_t gpa)
{
	generic_svm_setup(svm, l2_code);

	asm volatile ("vmrun %[gpa]" : : [gpa] "a" (gpa) : "memory");
}

static void l1_vmload(struct svm_test_data *svm, gpa_t gpa)
{
	generic_svm_setup(svm, l2_code);

	asm volatile ("vmload %[gpa]" : : [gpa] "a" (gpa) : "memory");
}

static void l1_vmsave(struct svm_test_data *svm, gpa_t gpa)
{
	generic_svm_setup(svm, l2_code);

	asm volatile ("vmsave %[gpa]" : : [gpa] "a" (gpa) : "memory");
}

static void l1_vmexit(struct svm_test_data *svm, gpa_t gpa)
{
	generic_svm_setup(svm, l2_code);

	run_guest(svm->vmcb, svm->vmcb_gpa);
	GUEST_ASSERT(svm->vmcb->control.exit_code == SVM_EXIT_VMMCALL);
	GUEST_DONE();
}

static u64 unmappable_gpa(struct kvm_vcpu *vcpu)
{
	struct userspace_mem_region *region;
	u64 region_gpa_end, vm_gpa_end = 0;
	int i;

	hash_for_each(vcpu->vm->regions.slot_hash, i, region, slot_node) {
		region_gpa_end = region->region.guest_phys_addr + region->region.memory_size;
		vm_gpa_end = max(vm_gpa_end, region_gpa_end);
	}

	return vm_gpa_end;
}

static void test_invalid_vmcb12(struct kvm_vcpu *vcpu)
{
	gva_t nested_gva = 0;
	struct ucall uc;


	vm_install_exception_handler(vcpu->vm, GP_VECTOR, guest_gp_handler);
	vcpu_alloc_svm(vcpu->vm, &nested_gva);
	vcpu_args_set(vcpu, 2, nested_gva, -1ULL);
	vcpu_run(vcpu);

	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT_EQ(get_ucall(vcpu, &uc), UCALL_SYNC);
	TEST_ASSERT_EQ(uc.args[1], SYNC_GP);
}

static void test_unmappable_vmcb12(struct kvm_vcpu *vcpu)
{
	gva_t nested_gva = 0;

	vcpu_alloc_svm(vcpu->vm, &nested_gva);
	vcpu_args_set(vcpu, 2, nested_gva, unmappable_gpa(vcpu));
	vcpu_run(vcpu);

	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);
	TEST_ASSERT_EQ(vcpu->run->emulation_failure.suberror, KVM_INTERNAL_ERROR_EMULATION);
}

static void test_unmappable_vmcb12_vmexit(struct kvm_vcpu *vcpu)
{
	struct kvm_x86_state *state;
	gva_t nested_gva = 0;
	struct ucall uc;

	/*
	 * Enter L2 (with a legit vmcb12 GPA), then overwrite vmcb12 GPA with an
	 * unmappable GPA. KVM will fail to map vmcb12 on nested VM-Exit and
	 * cause a shutdown.
	 */
	vcpu_alloc_svm(vcpu->vm, &nested_gva);
	vcpu_args_set(vcpu, 2, nested_gva, unmappable_gpa(vcpu));
	vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
	TEST_ASSERT_EQ(get_ucall(vcpu, &uc), UCALL_SYNC);
	TEST_ASSERT_EQ(uc.args[1], SYNC_L2_STARTED);

	state = vcpu_save_state(vcpu);
	state->nested.hdr.svm.vmcb_pa = unmappable_gpa(vcpu);
	vcpu_load_state(vcpu, state);
	vcpu_run(vcpu);
	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_SHUTDOWN);

	kvm_x86_state_cleanup(state);
}

KVM_ONE_VCPU_TEST_SUITE(vmcb12_gpa);

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmrun_invalid, l1_vmrun)
{
	test_invalid_vmcb12(vcpu);
}

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmload_invalid, l1_vmload)
{
	test_invalid_vmcb12(vcpu);
}

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmsave_invalid, l1_vmsave)
{
	test_invalid_vmcb12(vcpu);
}

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmrun_unmappable, l1_vmrun)
{
	test_unmappable_vmcb12(vcpu);
}

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmload_unmappable, l1_vmload)
{
	test_unmappable_vmcb12(vcpu);
}

KVM_ONE_VCPU_TEST(vmcb12_gpa, vmsave_unmappable, l1_vmsave)
{
	test_unmappable_vmcb12(vcpu);
}

/*
 * Invalid vmcb12_gpa cannot be test for #VMEXIT as KVM_SET_NESTED_STATE will
 * reject it.
 */
KVM_ONE_VCPU_TEST(vmcb12_gpa, vmexit_unmappable, l1_vmexit)
{
	test_unmappable_vmcb12_vmexit(vcpu);
}

int main(int argc, char *argv[])
{
	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM));

	return test_harness_run(argc, argv);
}