1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * vmx_apic_access_test
4 *
5 * Copyright (C) 2020, Google LLC.
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2.
8 *
9 * The first subtest simply checks to see that an L2 guest can be
10 * launched with a valid APIC-access address that is backed by a
11 * page of L1 physical memory.
12 *
13 * The second subtest sets the APIC-access address to a (valid) L1
14 * physical address that is not backed by memory. KVM can't handle
15 * this situation, so resuming L2 should result in a KVM exit for
16 * internal error (emulation). This is not an architectural
17 * requirement. It is just a shortcoming of KVM. The internal error
18 * is unfortunate, but it's better than what used to happen!
19 */
20
21 #include "test_util.h"
22 #include "kvm_util.h"
23 #include "processor.h"
24 #include "vmx.h"
25
26 #include <string.h>
27 #include <sys/ioctl.h>
28
29 #include "kselftest.h"
30
31 static void l2_guest_code(void)
32 {
33 /* Exit to L1 */
34 __asm__ __volatile__("vmcall");
35 }
36
37 static void l1_guest_code(struct vmx_pages *vmx_pages, unsigned long high_gpa)
38 {
39 #define L2_GUEST_STACK_SIZE 64
40 unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
41 uint32_t control;
42
43 GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
44 GUEST_ASSERT(load_vmcs(vmx_pages));
45
46 /* Prepare the VMCS for L2 execution. */
47 prepare_vmcs(vmx_pages, l2_guest_code,
48 &l2_guest_stack[L2_GUEST_STACK_SIZE]);
49 control = vmreadz(CPU_BASED_VM_EXEC_CONTROL);
50 control |= CPU_BASED_ACTIVATE_SECONDARY_CONTROLS;
51 vmwrite(CPU_BASED_VM_EXEC_CONTROL, control);
52 control = vmreadz(SECONDARY_VM_EXEC_CONTROL);
53 control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
54 vmwrite(SECONDARY_VM_EXEC_CONTROL, control);
55 vmwrite(APIC_ACCESS_ADDR, vmx_pages->apic_access_gpa);
56
57 /* Try to launch L2 with the memory-backed APIC-access address. */
58 GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
59 GUEST_ASSERT(!vmlaunch());
60 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
61
62 vmwrite(APIC_ACCESS_ADDR, high_gpa);
63
64 /* Try to resume L2 with the unbacked APIC-access address. */
65 GUEST_SYNC(vmreadz(APIC_ACCESS_ADDR));
66 GUEST_ASSERT(!vmresume());
67 GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
68
69 GUEST_DONE();
70 }
71
72 int main(int argc, char *argv[])
73 {
74 unsigned long apic_access_addr = ~0ul;
75 vm_vaddr_t vmx_pages_gva;
76 unsigned long high_gpa;
77 struct vmx_pages *vmx;
78 bool done = false;
79
80 struct kvm_vcpu *vcpu;
81 struct kvm_vm *vm;
82
83 TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
84
85 vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
86
87 high_gpa = (vm->max_gfn - 1) << vm->page_shift;
88
89 vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
90 prepare_virtualize_apic_accesses(vmx, vm);
91 vcpu_args_set(vcpu, 2, vmx_pages_gva, high_gpa);
92
93 while (!done) {
94 volatile struct kvm_run *run = vcpu->run;
95 struct ucall uc;
96
97 vcpu_run(vcpu);
98 if (apic_access_addr == high_gpa) {
99 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);
100 TEST_ASSERT(run->internal.suberror ==
101 KVM_INTERNAL_ERROR_EMULATION,
102 "Got internal suberror other than KVM_INTERNAL_ERROR_EMULATION: %u",
103 run->internal.suberror);
104 break;
105 }
106 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
107
108 switch (get_ucall(vcpu, &uc)) {
109 case UCALL_ABORT:
110 REPORT_GUEST_ASSERT(uc);
111 /* NOT REACHED */
112 case UCALL_SYNC:
113 apic_access_addr = uc.args[1];
114 break;
115 case UCALL_DONE:
116 done = true;
117 break;
118 default:
119 TEST_ASSERT(false, "Unknown ucall %lu", uc.cmd);
120 }
121 }
122 kvm_vm_free(vm);
123 return 0;
124 }
125
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