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