1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2015, 2016 ARM Ltd.
4 */
5
6 #include <linux/uaccess.h>
7 #include <linux/interrupt.h>
8 #include <linux/cpu.h>
9 #include <linux/kvm_host.h>
10 #include <kvm/arm_vgic.h>
11 #include <asm/kvm_emulate.h>
12 #include <asm/kvm_mmu.h>
13 #include "vgic.h"
14
15 /*
16 * Initialization rules: there are multiple stages to the vgic
17 * initialization, both for the distributor and the CPU interfaces. The basic
18 * idea is that even though the VGIC is not functional or not requested from
19 * user space, the critical path of the run loop can still call VGIC functions
20 * that just won't do anything, without them having to check additional
21 * initialization flags to ensure they don't look at uninitialized data
22 * structures.
23 *
24 * Distributor:
25 *
26 * - kvm_vgic_early_init(): initialization of static data that doesn't
27 * depend on any sizing information or emulation type. No allocation
28 * is allowed there.
29 *
30 * - vgic_init(): allocation and initialization of the generic data
31 * structures that depend on sizing information (number of CPUs,
32 * number of interrupts). Also initializes the vcpu specific data
33 * structures. Can be executed lazily for GICv2.
34 *
35 * CPU Interface:
36 *
37 * - kvm_vgic_vcpu_init(): initialization of static data that
38 * doesn't depend on any sizing information or emulation type. No
39 * allocation is allowed there.
40 */
41
42 /* EARLY INIT */
43
44 /**
45 * kvm_vgic_early_init() - Initialize static VGIC VCPU data structures
46 * @kvm: The VM whose VGIC districutor should be initialized
47 *
48 * Only do initialization of static structures that don't require any
49 * allocation or sizing information from userspace. vgic_init() called
50 * kvm_vgic_dist_init() which takes care of the rest.
51 */
kvm_vgic_early_init(struct kvm * kvm)52 void kvm_vgic_early_init(struct kvm *kvm)
53 {
54 struct vgic_dist *dist = &kvm->arch.vgic;
55
56 INIT_LIST_HEAD(&dist->lpi_list_head);
57 INIT_LIST_HEAD(&dist->lpi_translation_cache);
58 raw_spin_lock_init(&dist->lpi_list_lock);
59 }
60
61 /* CREATION */
62
63 /**
64 * kvm_vgic_create: triggered by the instantiation of the VGIC device by
65 * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
66 * or through the generic KVM_CREATE_DEVICE API ioctl.
67 * irqchip_in_kernel() tells you if this function succeeded or not.
68 * @kvm: kvm struct pointer
69 * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
70 */
kvm_vgic_create(struct kvm * kvm,u32 type)71 int kvm_vgic_create(struct kvm *kvm, u32 type)
72 {
73 int i, ret;
74 struct kvm_vcpu *vcpu;
75
76 if (irqchip_in_kernel(kvm))
77 return -EEXIST;
78
79 /*
80 * This function is also called by the KVM_CREATE_IRQCHIP handler,
81 * which had no chance yet to check the availability of the GICv2
82 * emulation. So check this here again. KVM_CREATE_DEVICE does
83 * the proper checks already.
84 */
85 if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
86 !kvm_vgic_global_state.can_emulate_gicv2)
87 return -ENODEV;
88
89 ret = -EBUSY;
90 if (!lock_all_vcpus(kvm))
91 return ret;
92
93 kvm_for_each_vcpu(i, vcpu, kvm) {
94 if (vcpu->arch.has_run_once)
95 goto out_unlock;
96 }
97 ret = 0;
98
99 if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
100 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
101 else
102 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
103
104 if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
105 ret = -E2BIG;
106 goto out_unlock;
107 }
108
109 kvm->arch.vgic.in_kernel = true;
110 kvm->arch.vgic.vgic_model = type;
111
112 kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
113
114 if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
115 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
116 else
117 INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
118
119 out_unlock:
120 unlock_all_vcpus(kvm);
121 return ret;
122 }
123
124 /* INIT/DESTROY */
125
126 /**
127 * kvm_vgic_dist_init: initialize the dist data structures
128 * @kvm: kvm struct pointer
129 * @nr_spis: number of spis, frozen by caller
130 */
kvm_vgic_dist_init(struct kvm * kvm,unsigned int nr_spis)131 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
132 {
133 struct vgic_dist *dist = &kvm->arch.vgic;
134 struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
135 int i;
136
137 dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
138 if (!dist->spis)
139 return -ENOMEM;
140
141 /*
142 * In the following code we do not take the irq struct lock since
143 * no other action on irq structs can happen while the VGIC is
144 * not initialized yet:
145 * If someone wants to inject an interrupt or does a MMIO access, we
146 * require prior initialization in case of a virtual GICv3 or trigger
147 * initialization when using a virtual GICv2.
148 */
149 for (i = 0; i < nr_spis; i++) {
150 struct vgic_irq *irq = &dist->spis[i];
151
152 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
153 INIT_LIST_HEAD(&irq->ap_list);
154 raw_spin_lock_init(&irq->irq_lock);
155 irq->vcpu = NULL;
156 irq->target_vcpu = vcpu0;
157 kref_init(&irq->refcount);
158 switch (dist->vgic_model) {
159 case KVM_DEV_TYPE_ARM_VGIC_V2:
160 irq->targets = 0;
161 irq->group = 0;
162 break;
163 case KVM_DEV_TYPE_ARM_VGIC_V3:
164 irq->mpidr = 0;
165 irq->group = 1;
166 break;
167 default:
168 kfree(dist->spis);
169 dist->spis = NULL;
170 return -EINVAL;
171 }
172 }
173 return 0;
174 }
175
176 /**
177 * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
178 * structures and register VCPU-specific KVM iodevs
179 *
180 * @vcpu: pointer to the VCPU being created and initialized
181 *
182 * Only do initialization, but do not actually enable the
183 * VGIC CPU interface
184 */
kvm_vgic_vcpu_init(struct kvm_vcpu * vcpu)185 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
186 {
187 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
188 struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
189 int ret = 0;
190 int i;
191
192 vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
193
194 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
195 raw_spin_lock_init(&vgic_cpu->ap_list_lock);
196 atomic_set(&vgic_cpu->vgic_v3.its_vpe.vlpi_count, 0);
197
198 /*
199 * Enable and configure all SGIs to be edge-triggered and
200 * configure all PPIs as level-triggered.
201 */
202 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
203 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
204
205 INIT_LIST_HEAD(&irq->ap_list);
206 raw_spin_lock_init(&irq->irq_lock);
207 irq->intid = i;
208 irq->vcpu = NULL;
209 irq->target_vcpu = vcpu;
210 kref_init(&irq->refcount);
211 if (vgic_irq_is_sgi(i)) {
212 /* SGIs */
213 irq->enabled = 1;
214 irq->config = VGIC_CONFIG_EDGE;
215 } else {
216 /* PPIs */
217 irq->config = VGIC_CONFIG_LEVEL;
218 }
219 }
220
221 if (!irqchip_in_kernel(vcpu->kvm))
222 return 0;
223
224 /*
225 * If we are creating a VCPU with a GICv3 we must also register the
226 * KVM io device for the redistributor that belongs to this VCPU.
227 */
228 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
229 mutex_lock(&vcpu->kvm->lock);
230 ret = vgic_register_redist_iodev(vcpu);
231 mutex_unlock(&vcpu->kvm->lock);
232 }
233 return ret;
234 }
235
kvm_vgic_vcpu_enable(struct kvm_vcpu * vcpu)236 static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
237 {
238 if (kvm_vgic_global_state.type == VGIC_V2)
239 vgic_v2_enable(vcpu);
240 else
241 vgic_v3_enable(vcpu);
242 }
243
244 /*
245 * vgic_init: allocates and initializes dist and vcpu data structures
246 * depending on two dimensioning parameters:
247 * - the number of spis
248 * - the number of vcpus
249 * The function is generally called when nr_spis has been explicitly set
250 * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
251 * vgic_initialized() returns true when this function has succeeded.
252 * Must be called with kvm->lock held!
253 */
vgic_init(struct kvm * kvm)254 int vgic_init(struct kvm *kvm)
255 {
256 struct vgic_dist *dist = &kvm->arch.vgic;
257 struct kvm_vcpu *vcpu;
258 int ret = 0, i, idx;
259
260 if (vgic_initialized(kvm))
261 return 0;
262
263 /* Are we also in the middle of creating a VCPU? */
264 if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
265 return -EBUSY;
266
267 /* freeze the number of spis */
268 if (!dist->nr_spis)
269 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
270
271 ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
272 if (ret)
273 goto out;
274
275 /* Initialize groups on CPUs created before the VGIC type was known */
276 kvm_for_each_vcpu(idx, vcpu, kvm) {
277 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
278
279 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
280 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
281 switch (dist->vgic_model) {
282 case KVM_DEV_TYPE_ARM_VGIC_V3:
283 irq->group = 1;
284 irq->mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
285 break;
286 case KVM_DEV_TYPE_ARM_VGIC_V2:
287 irq->group = 0;
288 irq->targets = 1U << idx;
289 break;
290 default:
291 ret = -EINVAL;
292 goto out;
293 }
294 }
295 }
296
297 if (vgic_has_its(kvm))
298 vgic_lpi_translation_cache_init(kvm);
299
300 /*
301 * If we have GICv4.1 enabled, unconditionnaly request enable the
302 * v4 support so that we get HW-accelerated vSGIs. Otherwise, only
303 * enable it if we present a virtual ITS to the guest.
304 */
305 if (vgic_supports_direct_msis(kvm)) {
306 ret = vgic_v4_init(kvm);
307 if (ret)
308 goto out;
309 }
310
311 kvm_for_each_vcpu(i, vcpu, kvm)
312 kvm_vgic_vcpu_enable(vcpu);
313
314 ret = kvm_vgic_setup_default_irq_routing(kvm);
315 if (ret)
316 goto out;
317
318 vgic_debug_init(kvm);
319
320 dist->implementation_rev = 2;
321 dist->initialized = true;
322
323 out:
324 return ret;
325 }
326
kvm_vgic_dist_destroy(struct kvm * kvm)327 static void kvm_vgic_dist_destroy(struct kvm *kvm)
328 {
329 struct vgic_dist *dist = &kvm->arch.vgic;
330 struct vgic_redist_region *rdreg, *next;
331
332 dist->ready = false;
333 dist->initialized = false;
334
335 kfree(dist->spis);
336 dist->spis = NULL;
337 dist->nr_spis = 0;
338
339 if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
340 list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
341 list_del(&rdreg->list);
342 kfree(rdreg);
343 }
344 INIT_LIST_HEAD(&dist->rd_regions);
345 }
346
347 if (vgic_has_its(kvm))
348 vgic_lpi_translation_cache_destroy(kvm);
349
350 if (vgic_supports_direct_msis(kvm))
351 vgic_v4_teardown(kvm);
352 }
353
kvm_vgic_vcpu_destroy(struct kvm_vcpu * vcpu)354 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
355 {
356 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
357
358 /*
359 * Retire all pending LPIs on this vcpu anyway as we're
360 * going to destroy it.
361 */
362 vgic_flush_pending_lpis(vcpu);
363
364 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
365 }
366
367 /* To be called with kvm->lock held */
__kvm_vgic_destroy(struct kvm * kvm)368 static void __kvm_vgic_destroy(struct kvm *kvm)
369 {
370 struct kvm_vcpu *vcpu;
371 int i;
372
373 vgic_debug_destroy(kvm);
374
375 kvm_for_each_vcpu(i, vcpu, kvm)
376 kvm_vgic_vcpu_destroy(vcpu);
377
378 kvm_vgic_dist_destroy(kvm);
379 }
380
kvm_vgic_destroy(struct kvm * kvm)381 void kvm_vgic_destroy(struct kvm *kvm)
382 {
383 mutex_lock(&kvm->lock);
384 __kvm_vgic_destroy(kvm);
385 mutex_unlock(&kvm->lock);
386 }
387
388 /**
389 * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
390 * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
391 * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
392 * @kvm: kvm struct pointer
393 */
vgic_lazy_init(struct kvm * kvm)394 int vgic_lazy_init(struct kvm *kvm)
395 {
396 int ret = 0;
397
398 if (unlikely(!vgic_initialized(kvm))) {
399 /*
400 * We only provide the automatic initialization of the VGIC
401 * for the legacy case of a GICv2. Any other type must
402 * be explicitly initialized once setup with the respective
403 * KVM device call.
404 */
405 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
406 return -EBUSY;
407
408 mutex_lock(&kvm->lock);
409 ret = vgic_init(kvm);
410 mutex_unlock(&kvm->lock);
411 }
412
413 return ret;
414 }
415
416 /* RESOURCE MAPPING */
417
418 /**
419 * Map the MMIO regions depending on the VGIC model exposed to the guest
420 * called on the first VCPU run.
421 * Also map the virtual CPU interface into the VM.
422 * v2/v3 derivatives call vgic_init if not already done.
423 * vgic_ready() returns true if this function has succeeded.
424 * @kvm: kvm struct pointer
425 */
kvm_vgic_map_resources(struct kvm * kvm)426 int kvm_vgic_map_resources(struct kvm *kvm)
427 {
428 struct vgic_dist *dist = &kvm->arch.vgic;
429 int ret = 0;
430
431 mutex_lock(&kvm->lock);
432 if (!irqchip_in_kernel(kvm))
433 goto out;
434
435 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
436 ret = vgic_v2_map_resources(kvm);
437 else
438 ret = vgic_v3_map_resources(kvm);
439
440 if (ret)
441 __kvm_vgic_destroy(kvm);
442
443 out:
444 mutex_unlock(&kvm->lock);
445 return ret;
446 }
447
448 /* GENERIC PROBE */
449
vgic_init_cpu_starting(unsigned int cpu)450 static int vgic_init_cpu_starting(unsigned int cpu)
451 {
452 enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
453 return 0;
454 }
455
456
vgic_init_cpu_dying(unsigned int cpu)457 static int vgic_init_cpu_dying(unsigned int cpu)
458 {
459 disable_percpu_irq(kvm_vgic_global_state.maint_irq);
460 return 0;
461 }
462
vgic_maintenance_handler(int irq,void * data)463 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
464 {
465 /*
466 * We cannot rely on the vgic maintenance interrupt to be
467 * delivered synchronously. This means we can only use it to
468 * exit the VM, and we perform the handling of EOIed
469 * interrupts on the exit path (see vgic_fold_lr_state).
470 */
471 return IRQ_HANDLED;
472 }
473
474 /**
475 * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
476 *
477 * For a specific CPU, initialize the GIC VE hardware.
478 */
kvm_vgic_init_cpu_hardware(void)479 void kvm_vgic_init_cpu_hardware(void)
480 {
481 BUG_ON(preemptible());
482
483 /*
484 * We want to make sure the list registers start out clear so that we
485 * only have the program the used registers.
486 */
487 if (kvm_vgic_global_state.type == VGIC_V2)
488 vgic_v2_init_lrs();
489 else
490 kvm_call_hyp(__vgic_v3_init_lrs);
491 }
492
493 /**
494 * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
495 * according to the host GIC model. Accordingly calls either
496 * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
497 * instantiated by a guest later on .
498 */
kvm_vgic_hyp_init(void)499 int kvm_vgic_hyp_init(void)
500 {
501 const struct gic_kvm_info *gic_kvm_info;
502 int ret;
503
504 gic_kvm_info = gic_get_kvm_info();
505 if (!gic_kvm_info)
506 return -ENODEV;
507
508 if (!gic_kvm_info->maint_irq) {
509 kvm_err("No vgic maintenance irq\n");
510 return -ENXIO;
511 }
512
513 switch (gic_kvm_info->type) {
514 case GIC_V2:
515 ret = vgic_v2_probe(gic_kvm_info);
516 break;
517 case GIC_V3:
518 ret = vgic_v3_probe(gic_kvm_info);
519 if (!ret) {
520 static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
521 kvm_info("GIC system register CPU interface enabled\n");
522 }
523 break;
524 default:
525 ret = -ENODEV;
526 }
527
528 if (ret)
529 return ret;
530
531 kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
532 ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
533 vgic_maintenance_handler,
534 "vgic", kvm_get_running_vcpus());
535 if (ret) {
536 kvm_err("Cannot register interrupt %d\n",
537 kvm_vgic_global_state.maint_irq);
538 return ret;
539 }
540
541 ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
542 "kvm/arm/vgic:starting",
543 vgic_init_cpu_starting, vgic_init_cpu_dying);
544 if (ret) {
545 kvm_err("Cannot register vgic CPU notifier\n");
546 goto out_free_irq;
547 }
548
549 kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
550 return 0;
551
552 out_free_irq:
553 free_percpu_irq(kvm_vgic_global_state.maint_irq,
554 kvm_get_running_vcpus());
555 return ret;
556 }
557