1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2019 Arm Ltd.
3
4 #include <linux/arm-smccc.h>
5 #include <linux/kvm_host.h>
6
7 #include <asm/kvm_emulate.h>
8
9 #include <kvm/arm_hypercalls.h>
10 #include <kvm/arm_psci.h>
11
12 #define KVM_ARM_SMCCC_STD_FEATURES \
13 GENMASK(KVM_REG_ARM_STD_BMAP_BIT_COUNT - 1, 0)
14 #define KVM_ARM_SMCCC_STD_HYP_FEATURES \
15 GENMASK(KVM_REG_ARM_STD_HYP_BMAP_BIT_COUNT - 1, 0)
16 #define KVM_ARM_SMCCC_VENDOR_HYP_FEATURES \
17 GENMASK(KVM_REG_ARM_VENDOR_HYP_BMAP_BIT_COUNT - 1, 0)
18
kvm_ptp_get_time(struct kvm_vcpu * vcpu,u64 * val)19 static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
20 {
21 struct system_time_snapshot systime_snapshot;
22 u64 cycles = ~0UL;
23 u32 feature;
24
25 /*
26 * system time and counter value must captured at the same
27 * time to keep consistency and precision.
28 */
29 ktime_get_snapshot(&systime_snapshot);
30
31 /*
32 * This is only valid if the current clocksource is the
33 * architected counter, as this is the only one the guest
34 * can see.
35 */
36 if (systime_snapshot.cs_id != CSID_ARM_ARCH_COUNTER)
37 return;
38
39 /*
40 * The guest selects one of the two reference counters
41 * (virtual or physical) with the first argument of the SMCCC
42 * call. In case the identifier is not supported, error out.
43 */
44 feature = smccc_get_arg1(vcpu);
45 switch (feature) {
46 case KVM_PTP_VIRT_COUNTER:
47 cycles = systime_snapshot.cycles - vcpu_read_sys_reg(vcpu, CNTVOFF_EL2);
48 break;
49 case KVM_PTP_PHYS_COUNTER:
50 cycles = systime_snapshot.cycles;
51 break;
52 default:
53 return;
54 }
55
56 /*
57 * This relies on the top bit of val[0] never being set for
58 * valid values of system time, because that is *really* far
59 * in the future (about 292 years from 1970, and at that stage
60 * nobody will give a damn about it).
61 */
62 val[0] = upper_32_bits(systime_snapshot.real);
63 val[1] = lower_32_bits(systime_snapshot.real);
64 val[2] = upper_32_bits(cycles);
65 val[3] = lower_32_bits(cycles);
66 }
67
kvm_hvc_call_default_allowed(u32 func_id)68 static bool kvm_hvc_call_default_allowed(u32 func_id)
69 {
70 switch (func_id) {
71 /*
72 * List of function-ids that are not gated with the bitmapped
73 * feature firmware registers, and are to be allowed for
74 * servicing the call by default.
75 */
76 case ARM_SMCCC_VERSION_FUNC_ID:
77 case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
78 return true;
79 default:
80 /* PSCI 0.2 and up is in the 0:0x1f range */
81 if (ARM_SMCCC_OWNER_NUM(func_id) == ARM_SMCCC_OWNER_STANDARD &&
82 ARM_SMCCC_FUNC_NUM(func_id) <= 0x1f)
83 return true;
84
85 /*
86 * KVM's PSCI 0.1 doesn't comply with SMCCC, and has
87 * its own function-id base and range
88 */
89 if (func_id >= KVM_PSCI_FN(0) && func_id <= KVM_PSCI_FN(3))
90 return true;
91
92 return false;
93 }
94 }
95
kvm_hvc_call_allowed(struct kvm_vcpu * vcpu,u32 func_id)96 static bool kvm_hvc_call_allowed(struct kvm_vcpu *vcpu, u32 func_id)
97 {
98 struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
99
100 switch (func_id) {
101 case ARM_SMCCC_TRNG_VERSION:
102 case ARM_SMCCC_TRNG_FEATURES:
103 case ARM_SMCCC_TRNG_GET_UUID:
104 case ARM_SMCCC_TRNG_RND32:
105 case ARM_SMCCC_TRNG_RND64:
106 return test_bit(KVM_REG_ARM_STD_BIT_TRNG_V1_0,
107 &smccc_feat->std_bmap);
108 case ARM_SMCCC_HV_PV_TIME_FEATURES:
109 case ARM_SMCCC_HV_PV_TIME_ST:
110 return test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
111 &smccc_feat->std_hyp_bmap);
112 case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
113 case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
114 return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_FUNC_FEAT,
115 &smccc_feat->vendor_hyp_bmap);
116 case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
117 return test_bit(KVM_REG_ARM_VENDOR_HYP_BIT_PTP,
118 &smccc_feat->vendor_hyp_bmap);
119 default:
120 return kvm_hvc_call_default_allowed(func_id);
121 }
122 }
123
kvm_hvc_call_handler(struct kvm_vcpu * vcpu)124 int kvm_hvc_call_handler(struct kvm_vcpu *vcpu)
125 {
126 struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
127 u32 func_id = smccc_get_function(vcpu);
128 u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
129 u32 feature;
130 gpa_t gpa;
131
132 if (!kvm_hvc_call_allowed(vcpu, func_id))
133 goto out;
134
135 switch (func_id) {
136 case ARM_SMCCC_VERSION_FUNC_ID:
137 val[0] = ARM_SMCCC_VERSION_1_1;
138 break;
139 case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
140 feature = smccc_get_arg1(vcpu);
141 switch (feature) {
142 case ARM_SMCCC_ARCH_WORKAROUND_1:
143 switch (arm64_get_spectre_v2_state()) {
144 case SPECTRE_VULNERABLE:
145 break;
146 case SPECTRE_MITIGATED:
147 val[0] = SMCCC_RET_SUCCESS;
148 break;
149 case SPECTRE_UNAFFECTED:
150 val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
151 break;
152 }
153 break;
154 case ARM_SMCCC_ARCH_WORKAROUND_2:
155 switch (arm64_get_spectre_v4_state()) {
156 case SPECTRE_VULNERABLE:
157 break;
158 case SPECTRE_MITIGATED:
159 /*
160 * SSBS everywhere: Indicate no firmware
161 * support, as the SSBS support will be
162 * indicated to the guest and the default is
163 * safe.
164 *
165 * Otherwise, expose a permanent mitigation
166 * to the guest, and hide SSBS so that the
167 * guest stays protected.
168 */
169 if (cpus_have_final_cap(ARM64_SSBS))
170 break;
171 fallthrough;
172 case SPECTRE_UNAFFECTED:
173 val[0] = SMCCC_RET_NOT_REQUIRED;
174 break;
175 }
176 break;
177 case ARM_SMCCC_ARCH_WORKAROUND_3:
178 switch (arm64_get_spectre_bhb_state()) {
179 case SPECTRE_VULNERABLE:
180 break;
181 case SPECTRE_MITIGATED:
182 val[0] = SMCCC_RET_SUCCESS;
183 break;
184 case SPECTRE_UNAFFECTED:
185 val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
186 break;
187 }
188 break;
189 case ARM_SMCCC_HV_PV_TIME_FEATURES:
190 if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
191 &smccc_feat->std_hyp_bmap))
192 val[0] = SMCCC_RET_SUCCESS;
193 break;
194 }
195 break;
196 case ARM_SMCCC_HV_PV_TIME_FEATURES:
197 val[0] = kvm_hypercall_pv_features(vcpu);
198 break;
199 case ARM_SMCCC_HV_PV_TIME_ST:
200 gpa = kvm_init_stolen_time(vcpu);
201 if (gpa != GPA_INVALID)
202 val[0] = gpa;
203 break;
204 case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
205 val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
206 val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
207 val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2;
208 val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
209 break;
210 case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
211 val[0] = smccc_feat->vendor_hyp_bmap;
212 break;
213 case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
214 kvm_ptp_get_time(vcpu, val);
215 break;
216 case ARM_SMCCC_TRNG_VERSION:
217 case ARM_SMCCC_TRNG_FEATURES:
218 case ARM_SMCCC_TRNG_GET_UUID:
219 case ARM_SMCCC_TRNG_RND32:
220 case ARM_SMCCC_TRNG_RND64:
221 return kvm_trng_call(vcpu);
222 default:
223 return kvm_psci_call(vcpu);
224 }
225
226 out:
227 smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
228 return 1;
229 }
230
231 static const u64 kvm_arm_fw_reg_ids[] = {
232 KVM_REG_ARM_PSCI_VERSION,
233 KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1,
234 KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2,
235 KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3,
236 KVM_REG_ARM_STD_BMAP,
237 KVM_REG_ARM_STD_HYP_BMAP,
238 KVM_REG_ARM_VENDOR_HYP_BMAP,
239 };
240
kvm_arm_init_hypercalls(struct kvm * kvm)241 void kvm_arm_init_hypercalls(struct kvm *kvm)
242 {
243 struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
244
245 smccc_feat->std_bmap = KVM_ARM_SMCCC_STD_FEATURES;
246 smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;
247 smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
248 }
249
kvm_arm_get_fw_num_regs(struct kvm_vcpu * vcpu)250 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
251 {
252 return ARRAY_SIZE(kvm_arm_fw_reg_ids);
253 }
254
kvm_arm_copy_fw_reg_indices(struct kvm_vcpu * vcpu,u64 __user * uindices)255 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
256 {
257 int i;
258
259 for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
260 if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
261 return -EFAULT;
262 }
263
264 return 0;
265 }
266
267 #define KVM_REG_FEATURE_LEVEL_MASK GENMASK(3, 0)
268
269 /*
270 * Convert the workaround level into an easy-to-compare number, where higher
271 * values mean better protection.
272 */
get_kernel_wa_level(u64 regid)273 static int get_kernel_wa_level(u64 regid)
274 {
275 switch (regid) {
276 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
277 switch (arm64_get_spectre_v2_state()) {
278 case SPECTRE_VULNERABLE:
279 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
280 case SPECTRE_MITIGATED:
281 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL;
282 case SPECTRE_UNAFFECTED:
283 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED;
284 }
285 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL;
286 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
287 switch (arm64_get_spectre_v4_state()) {
288 case SPECTRE_MITIGATED:
289 /*
290 * As for the hypercall discovery, we pretend we
291 * don't have any FW mitigation if SSBS is there at
292 * all times.
293 */
294 if (cpus_have_final_cap(ARM64_SSBS))
295 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
296 fallthrough;
297 case SPECTRE_UNAFFECTED:
298 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
299 case SPECTRE_VULNERABLE:
300 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
301 }
302 break;
303 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
304 switch (arm64_get_spectre_bhb_state()) {
305 case SPECTRE_VULNERABLE:
306 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
307 case SPECTRE_MITIGATED:
308 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_AVAIL;
309 case SPECTRE_UNAFFECTED:
310 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_REQUIRED;
311 }
312 return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3_NOT_AVAIL;
313 }
314
315 return -EINVAL;
316 }
317
kvm_arm_get_fw_reg(struct kvm_vcpu * vcpu,const struct kvm_one_reg * reg)318 int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
319 {
320 struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
321 void __user *uaddr = (void __user *)(long)reg->addr;
322 u64 val;
323
324 switch (reg->id) {
325 case KVM_REG_ARM_PSCI_VERSION:
326 val = kvm_psci_version(vcpu);
327 break;
328 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
329 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
330 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
331 val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
332 break;
333 case KVM_REG_ARM_STD_BMAP:
334 val = READ_ONCE(smccc_feat->std_bmap);
335 break;
336 case KVM_REG_ARM_STD_HYP_BMAP:
337 val = READ_ONCE(smccc_feat->std_hyp_bmap);
338 break;
339 case KVM_REG_ARM_VENDOR_HYP_BMAP:
340 val = READ_ONCE(smccc_feat->vendor_hyp_bmap);
341 break;
342 default:
343 return -ENOENT;
344 }
345
346 if (copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)))
347 return -EFAULT;
348
349 return 0;
350 }
351
kvm_arm_set_fw_reg_bmap(struct kvm_vcpu * vcpu,u64 reg_id,u64 val)352 static int kvm_arm_set_fw_reg_bmap(struct kvm_vcpu *vcpu, u64 reg_id, u64 val)
353 {
354 int ret = 0;
355 struct kvm *kvm = vcpu->kvm;
356 struct kvm_smccc_features *smccc_feat = &kvm->arch.smccc_feat;
357 unsigned long *fw_reg_bmap, fw_reg_features;
358
359 switch (reg_id) {
360 case KVM_REG_ARM_STD_BMAP:
361 fw_reg_bmap = &smccc_feat->std_bmap;
362 fw_reg_features = KVM_ARM_SMCCC_STD_FEATURES;
363 break;
364 case KVM_REG_ARM_STD_HYP_BMAP:
365 fw_reg_bmap = &smccc_feat->std_hyp_bmap;
366 fw_reg_features = KVM_ARM_SMCCC_STD_HYP_FEATURES;
367 break;
368 case KVM_REG_ARM_VENDOR_HYP_BMAP:
369 fw_reg_bmap = &smccc_feat->vendor_hyp_bmap;
370 fw_reg_features = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;
371 break;
372 default:
373 return -ENOENT;
374 }
375
376 /* Check for unsupported bit */
377 if (val & ~fw_reg_features)
378 return -EINVAL;
379
380 mutex_lock(&kvm->lock);
381
382 if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &kvm->arch.flags) &&
383 val != *fw_reg_bmap) {
384 ret = -EBUSY;
385 goto out;
386 }
387
388 WRITE_ONCE(*fw_reg_bmap, val);
389 out:
390 mutex_unlock(&kvm->lock);
391 return ret;
392 }
393
kvm_arm_set_fw_reg(struct kvm_vcpu * vcpu,const struct kvm_one_reg * reg)394 int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
395 {
396 void __user *uaddr = (void __user *)(long)reg->addr;
397 u64 val;
398 int wa_level;
399
400 if (copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id)))
401 return -EFAULT;
402
403 switch (reg->id) {
404 case KVM_REG_ARM_PSCI_VERSION:
405 {
406 bool wants_02;
407
408 wants_02 = test_bit(KVM_ARM_VCPU_PSCI_0_2, vcpu->arch.features);
409
410 switch (val) {
411 case KVM_ARM_PSCI_0_1:
412 if (wants_02)
413 return -EINVAL;
414 vcpu->kvm->arch.psci_version = val;
415 return 0;
416 case KVM_ARM_PSCI_0_2:
417 case KVM_ARM_PSCI_1_0:
418 case KVM_ARM_PSCI_1_1:
419 if (!wants_02)
420 return -EINVAL;
421 vcpu->kvm->arch.psci_version = val;
422 return 0;
423 }
424 break;
425 }
426
427 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
428 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
429 if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
430 return -EINVAL;
431
432 if (get_kernel_wa_level(reg->id) < val)
433 return -EINVAL;
434
435 return 0;
436
437 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
438 if (val & ~(KVM_REG_FEATURE_LEVEL_MASK |
439 KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED))
440 return -EINVAL;
441
442 /* The enabled bit must not be set unless the level is AVAIL. */
443 if ((val & KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED) &&
444 (val & KVM_REG_FEATURE_LEVEL_MASK) != KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL)
445 return -EINVAL;
446
447 /*
448 * Map all the possible incoming states to the only two we
449 * really want to deal with.
450 */
451 switch (val & KVM_REG_FEATURE_LEVEL_MASK) {
452 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
453 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
454 wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
455 break;
456 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
457 case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
458 wa_level = KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED;
459 break;
460 default:
461 return -EINVAL;
462 }
463
464 /*
465 * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
466 * other way around.
467 */
468 if (get_kernel_wa_level(reg->id) < wa_level)
469 return -EINVAL;
470
471 return 0;
472 case KVM_REG_ARM_STD_BMAP:
473 case KVM_REG_ARM_STD_HYP_BMAP:
474 case KVM_REG_ARM_VENDOR_HYP_BMAP:
475 return kvm_arm_set_fw_reg_bmap(vcpu, reg->id, val);
476 default:
477 return -ENOENT;
478 }
479
480 return -EINVAL;
481 }
482
