1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * vmx_set_nested_state_test
4  *
5  * Copyright (C) 2019, Google LLC.
6  *
7  * This test verifies the integrity of calling the ioctl KVM_SET_NESTED_STATE.
8  */
9 
10 #include "test_util.h"
11 #include "kvm_util.h"
12 #include "processor.h"
13 #include "vmx.h"
14 
15 #include <errno.h>
16 #include <linux/kvm.h>
17 #include <string.h>
18 #include <sys/ioctl.h>
19 #include <unistd.h>
20 
21 /*
22  * Mirror of VMCS12_REVISION in arch/x86/kvm/vmx/vmcs12.h. If that value
23  * changes this should be updated.
24  */
25 #define VMCS12_REVISION 0x11e57ed0
26 #define VCPU_ID 5
27 
28 bool have_evmcs;
29 
test_nested_state(struct kvm_vm * vm,struct kvm_nested_state * state)30 void test_nested_state(struct kvm_vm *vm, struct kvm_nested_state *state)
31 {
32 	vcpu_nested_state_set(vm, VCPU_ID, state, false);
33 }
34 
test_nested_state_expect_errno(struct kvm_vm * vm,struct kvm_nested_state * state,int expected_errno)35 void test_nested_state_expect_errno(struct kvm_vm *vm,
36 				    struct kvm_nested_state *state,
37 				    int expected_errno)
38 {
39 	int rv;
40 
41 	rv = vcpu_nested_state_set(vm, VCPU_ID, state, true);
42 	TEST_ASSERT(rv == -1 && errno == expected_errno,
43 		"Expected %s (%d) from vcpu_nested_state_set but got rv: %i errno: %s (%d)",
44 		strerror(expected_errno), expected_errno, rv, strerror(errno),
45 		errno);
46 }
47 
test_nested_state_expect_einval(struct kvm_vm * vm,struct kvm_nested_state * state)48 void test_nested_state_expect_einval(struct kvm_vm *vm,
49 				     struct kvm_nested_state *state)
50 {
51 	test_nested_state_expect_errno(vm, state, EINVAL);
52 }
53 
test_nested_state_expect_efault(struct kvm_vm * vm,struct kvm_nested_state * state)54 void test_nested_state_expect_efault(struct kvm_vm *vm,
55 				     struct kvm_nested_state *state)
56 {
57 	test_nested_state_expect_errno(vm, state, EFAULT);
58 }
59 
set_revision_id_for_vmcs12(struct kvm_nested_state * state,u32 vmcs12_revision)60 void set_revision_id_for_vmcs12(struct kvm_nested_state *state,
61 				u32 vmcs12_revision)
62 {
63 	/* Set revision_id in vmcs12 to vmcs12_revision. */
64 	memcpy(&state->data, &vmcs12_revision, sizeof(u32));
65 }
66 
set_default_state(struct kvm_nested_state * state)67 void set_default_state(struct kvm_nested_state *state)
68 {
69 	memset(state, 0, sizeof(*state));
70 	state->flags = KVM_STATE_NESTED_RUN_PENDING |
71 		       KVM_STATE_NESTED_GUEST_MODE;
72 	state->format = 0;
73 	state->size = sizeof(*state);
74 }
75 
set_default_vmx_state(struct kvm_nested_state * state,int size)76 void set_default_vmx_state(struct kvm_nested_state *state, int size)
77 {
78 	memset(state, 0, size);
79 	if (have_evmcs)
80 		state->flags = KVM_STATE_NESTED_EVMCS;
81 	state->format = 0;
82 	state->size = size;
83 	state->hdr.vmx.vmxon_pa = 0x1000;
84 	state->hdr.vmx.vmcs12_pa = 0x2000;
85 	state->hdr.vmx.smm.flags = 0;
86 	set_revision_id_for_vmcs12(state, VMCS12_REVISION);
87 }
88 
test_vmx_nested_state(struct kvm_vm * vm)89 void test_vmx_nested_state(struct kvm_vm *vm)
90 {
91 	/* Add a page for VMCS12. */
92 	const int state_sz = sizeof(struct kvm_nested_state) + getpagesize();
93 	struct kvm_nested_state *state =
94 		(struct kvm_nested_state *)malloc(state_sz);
95 
96 	/* The format must be set to 0. 0 for VMX, 1 for SVM. */
97 	set_default_vmx_state(state, state_sz);
98 	state->format = 1;
99 	test_nested_state_expect_einval(vm, state);
100 
101 	/*
102 	 * We cannot virtualize anything if the guest does not have VMX
103 	 * enabled.
104 	 */
105 	set_default_vmx_state(state, state_sz);
106 	test_nested_state_expect_einval(vm, state);
107 
108 	/*
109 	 * We cannot virtualize anything if the guest does not have VMX
110 	 * enabled.  We expect KVM_SET_NESTED_STATE to return 0 if vmxon_pa
111 	 * is set to -1ull, but the flags must be zero.
112 	 */
113 	set_default_vmx_state(state, state_sz);
114 	state->hdr.vmx.vmxon_pa = -1ull;
115 	test_nested_state_expect_einval(vm, state);
116 
117 	state->hdr.vmx.vmcs12_pa = -1ull;
118 	state->flags = KVM_STATE_NESTED_EVMCS;
119 	test_nested_state_expect_einval(vm, state);
120 
121 	state->flags = 0;
122 	test_nested_state(vm, state);
123 
124 	/* Enable VMX in the guest CPUID. */
125 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
126 
127 	/*
128 	 * Setting vmxon_pa == -1ull and vmcs_pa == -1ull exits early without
129 	 * setting the nested state but flags other than eVMCS must be clear.
130 	 * The eVMCS flag can be set if the enlightened VMCS capability has
131 	 * been enabled.
132 	 */
133 	set_default_vmx_state(state, state_sz);
134 	state->hdr.vmx.vmxon_pa = -1ull;
135 	state->hdr.vmx.vmcs12_pa = -1ull;
136 	test_nested_state_expect_einval(vm, state);
137 
138 	state->flags &= KVM_STATE_NESTED_EVMCS;
139 	if (have_evmcs) {
140 		test_nested_state_expect_einval(vm, state);
141 		vcpu_enable_evmcs(vm, VCPU_ID);
142 	}
143 	test_nested_state(vm, state);
144 
145 	/* It is invalid to have vmxon_pa == -1ull and SMM flags non-zero. */
146 	state->hdr.vmx.smm.flags = 1;
147 	test_nested_state_expect_einval(vm, state);
148 
149 	/* Invalid flags are rejected. */
150 	set_default_vmx_state(state, state_sz);
151 	state->hdr.vmx.flags = ~0;
152 	test_nested_state_expect_einval(vm, state);
153 
154 	/* It is invalid to have vmxon_pa == -1ull and vmcs_pa != -1ull. */
155 	set_default_vmx_state(state, state_sz);
156 	state->hdr.vmx.vmxon_pa = -1ull;
157 	state->flags = 0;
158 	test_nested_state_expect_einval(vm, state);
159 
160 	/* It is invalid to have vmxon_pa set to a non-page aligned address. */
161 	set_default_vmx_state(state, state_sz);
162 	state->hdr.vmx.vmxon_pa = 1;
163 	test_nested_state_expect_einval(vm, state);
164 
165 	/*
166 	 * It is invalid to have KVM_STATE_NESTED_SMM_GUEST_MODE and
167 	 * KVM_STATE_NESTED_GUEST_MODE set together.
168 	 */
169 	set_default_vmx_state(state, state_sz);
170 	state->flags = KVM_STATE_NESTED_GUEST_MODE  |
171 		      KVM_STATE_NESTED_RUN_PENDING;
172 	state->hdr.vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
173 	test_nested_state_expect_einval(vm, state);
174 
175 	/*
176 	 * It is invalid to have any of the SMM flags set besides:
177 	 *	KVM_STATE_NESTED_SMM_GUEST_MODE
178 	 *	KVM_STATE_NESTED_SMM_VMXON
179 	 */
180 	set_default_vmx_state(state, state_sz);
181 	state->hdr.vmx.smm.flags = ~(KVM_STATE_NESTED_SMM_GUEST_MODE |
182 				KVM_STATE_NESTED_SMM_VMXON);
183 	test_nested_state_expect_einval(vm, state);
184 
185 	/* Outside SMM, SMM flags must be zero. */
186 	set_default_vmx_state(state, state_sz);
187 	state->flags = 0;
188 	state->hdr.vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE;
189 	test_nested_state_expect_einval(vm, state);
190 
191 	/*
192 	 * Size must be large enough to fit kvm_nested_state and vmcs12
193 	 * if VMCS12 physical address is set
194 	 */
195 	set_default_vmx_state(state, state_sz);
196 	state->size = sizeof(*state);
197 	state->flags = 0;
198 	test_nested_state_expect_einval(vm, state);
199 
200 	set_default_vmx_state(state, state_sz);
201 	state->size = sizeof(*state);
202 	state->flags = 0;
203 	state->hdr.vmx.vmcs12_pa = -1;
204 	test_nested_state(vm, state);
205 
206 	/*
207 	 * KVM_SET_NESTED_STATE succeeds with invalid VMCS
208 	 * contents but L2 not running.
209 	 */
210 	set_default_vmx_state(state, state_sz);
211 	state->flags = 0;
212 	test_nested_state(vm, state);
213 
214 	/* Invalid flags are rejected, even if no VMCS loaded. */
215 	set_default_vmx_state(state, state_sz);
216 	state->size = sizeof(*state);
217 	state->flags = 0;
218 	state->hdr.vmx.vmcs12_pa = -1;
219 	state->hdr.vmx.flags = ~0;
220 	test_nested_state_expect_einval(vm, state);
221 
222 	/* vmxon_pa cannot be the same address as vmcs_pa. */
223 	set_default_vmx_state(state, state_sz);
224 	state->hdr.vmx.vmxon_pa = 0;
225 	state->hdr.vmx.vmcs12_pa = 0;
226 	test_nested_state_expect_einval(vm, state);
227 
228 	/*
229 	 * Test that if we leave nesting the state reflects that when we get
230 	 * it again.
231 	 */
232 	set_default_vmx_state(state, state_sz);
233 	state->hdr.vmx.vmxon_pa = -1ull;
234 	state->hdr.vmx.vmcs12_pa = -1ull;
235 	state->flags = 0;
236 	test_nested_state(vm, state);
237 	vcpu_nested_state_get(vm, VCPU_ID, state);
238 	TEST_ASSERT(state->size >= sizeof(*state) && state->size <= state_sz,
239 		    "Size must be between %ld and %d.  The size returned was %d.",
240 		    sizeof(*state), state_sz, state->size);
241 	TEST_ASSERT(state->hdr.vmx.vmxon_pa == -1ull, "vmxon_pa must be -1ull.");
242 	TEST_ASSERT(state->hdr.vmx.vmcs12_pa == -1ull, "vmcs_pa must be -1ull.");
243 
244 	free(state);
245 }
246 
disable_vmx(struct kvm_vm * vm)247 void disable_vmx(struct kvm_vm *vm)
248 {
249 	struct kvm_cpuid2 *cpuid = kvm_get_supported_cpuid();
250 	int i;
251 
252 	for (i = 0; i < cpuid->nent; ++i)
253 		if (cpuid->entries[i].function == 1 &&
254 		    cpuid->entries[i].index == 0)
255 			break;
256 	TEST_ASSERT(i != cpuid->nent, "CPUID function 1 not found");
257 
258 	cpuid->entries[i].ecx &= ~CPUID_VMX;
259 	vcpu_set_cpuid(vm, VCPU_ID, cpuid);
260 	cpuid->entries[i].ecx |= CPUID_VMX;
261 }
262 
main(int argc,char * argv[])263 int main(int argc, char *argv[])
264 {
265 	struct kvm_vm *vm;
266 	struct kvm_nested_state state;
267 
268 	have_evmcs = kvm_check_cap(KVM_CAP_HYPERV_ENLIGHTENED_VMCS);
269 
270 	if (!kvm_check_cap(KVM_CAP_NESTED_STATE)) {
271 		print_skip("KVM_CAP_NESTED_STATE not available");
272 		exit(KSFT_SKIP);
273 	}
274 
275 	/*
276 	 * AMD currently does not implement set_nested_state, so for now we
277 	 * just early out.
278 	 */
279 	nested_vmx_check_supported();
280 
281 	vm = vm_create_default(VCPU_ID, 0, 0);
282 
283 	/*
284 	 * First run tests with VMX disabled to check error handling.
285 	 */
286 	disable_vmx(vm);
287 
288 	/* Passing a NULL kvm_nested_state causes a EFAULT. */
289 	test_nested_state_expect_efault(vm, NULL);
290 
291 	/* 'size' cannot be smaller than sizeof(kvm_nested_state). */
292 	set_default_state(&state);
293 	state.size = 0;
294 	test_nested_state_expect_einval(vm, &state);
295 
296 	/*
297 	 * Setting the flags 0xf fails the flags check.  The only flags that
298 	 * can be used are:
299 	 *     KVM_STATE_NESTED_GUEST_MODE
300 	 *     KVM_STATE_NESTED_RUN_PENDING
301 	 *     KVM_STATE_NESTED_EVMCS
302 	 */
303 	set_default_state(&state);
304 	state.flags = 0xf;
305 	test_nested_state_expect_einval(vm, &state);
306 
307 	/*
308 	 * If KVM_STATE_NESTED_RUN_PENDING is set then
309 	 * KVM_STATE_NESTED_GUEST_MODE has to be set as well.
310 	 */
311 	set_default_state(&state);
312 	state.flags = KVM_STATE_NESTED_RUN_PENDING;
313 	test_nested_state_expect_einval(vm, &state);
314 
315 	test_vmx_nested_state(vm);
316 
317 	kvm_vm_free(vm);
318 	return 0;
319 }
320