KVM: arm/arm64: vgic: Add refcounting for IRQs
[linux-2.6-block.git] / virt / kvm / arm / vgic / vgic-init.c
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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
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25/*
26 * Initialization rules: there are multiple stages to the vgic
27 * initialization, both for the distributor and the CPU interfaces.
28 *
29 * Distributor:
30 *
31 * - kvm_vgic_early_init(): initialization of static data that doesn't
32 * depend on any sizing information or emulation type. No allocation
33 * is allowed there.
34 *
35 * - vgic_init(): allocation and initialization of the generic data
36 * structures that depend on sizing information (number of CPUs,
37 * number of interrupts). Also initializes the vcpu specific data
38 * structures. Can be executed lazily for GICv2.
39 *
40 * CPU Interface:
41 *
42 * - kvm_vgic_cpu_early_init(): initialization of static data that
43 * doesn't depend on any sizing information or emulation type. No
44 * allocation is allowed there.
45 */
46
47/* EARLY INIT */
48
49/*
50 * Those 2 functions should not be needed anymore but they
51 * still are called from arm.c
52 */
53void kvm_vgic_early_init(struct kvm *kvm)
54{
55}
56
57void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
58{
59}
60
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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.
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68 * @kvm: kvm struct pointer
69 * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
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70 */
71int kvm_vgic_create(struct kvm *kvm, u32 type)
72{
73 int i, vcpu_lock_idx = -1, ret;
74 struct kvm_vcpu *vcpu;
75
76 mutex_lock(&kvm->lock);
77
78 if (irqchip_in_kernel(kvm)) {
79 ret = -EEXIST;
80 goto out;
81 }
82
83 /*
84 * This function is also called by the KVM_CREATE_IRQCHIP handler,
85 * which had no chance yet to check the availability of the GICv2
86 * emulation. So check this here again. KVM_CREATE_DEVICE does
87 * the proper checks already.
88 */
89 if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
90 !kvm_vgic_global_state.can_emulate_gicv2) {
91 ret = -ENODEV;
92 goto out;
93 }
94
95 /*
96 * Any time a vcpu is run, vcpu_load is called which tries to grab the
97 * vcpu->mutex. By grabbing the vcpu->mutex of all VCPUs we ensure
98 * that no other VCPUs are run while we create the vgic.
99 */
100 ret = -EBUSY;
101 kvm_for_each_vcpu(i, vcpu, kvm) {
102 if (!mutex_trylock(&vcpu->mutex))
103 goto out_unlock;
104 vcpu_lock_idx = i;
105 }
106
107 kvm_for_each_vcpu(i, vcpu, kvm) {
108 if (vcpu->arch.has_run_once)
109 goto out_unlock;
110 }
111 ret = 0;
112
113 if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
114 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
115 else
116 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
117
118 if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
119 ret = -E2BIG;
120 goto out_unlock;
121 }
122
123 kvm->arch.vgic.in_kernel = true;
124 kvm->arch.vgic.vgic_model = type;
125
126 /*
127 * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
128 * it is stored in distributor struct for asm save/restore purpose
129 */
130 kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
131
132 kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
133 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
134 kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
135
136out_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
142out:
143 mutex_unlock(&kvm->lock);
144 return ret;
145}
146
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147/* INIT/DESTROY */
148
149/**
150 * kvm_vgic_dist_init: initialize the dist data structures
151 * @kvm: kvm struct pointer
152 * @nr_spis: number of spis, frozen by caller
153 */
154static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
155{
156 struct vgic_dist *dist = &kvm->arch.vgic;
157 struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
158 int i;
159
160 dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
161 if (!dist->spis)
162 return -ENOMEM;
163
164 /*
165 * In the following code we do not take the irq struct lock since
166 * no other action on irq structs can happen while the VGIC is
167 * not initialized yet:
168 * If someone wants to inject an interrupt or does a MMIO access, we
169 * require prior initialization in case of a virtual GICv3 or trigger
170 * initialization when using a virtual GICv2.
171 */
172 for (i = 0; i < nr_spis; i++) {
173 struct vgic_irq *irq = &dist->spis[i];
174
175 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
176 INIT_LIST_HEAD(&irq->ap_list);
177 spin_lock_init(&irq->irq_lock);
178 irq->vcpu = NULL;
179 irq->target_vcpu = vcpu0;
5dd4b924 180 kref_init(&irq->refcount);
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181 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
182 irq->targets = 0;
183 else
184 irq->mpidr = 0;
185 }
186 return 0;
187}
188
189/**
190 * kvm_vgic_vcpu_init: initialize the vcpu data structures and
191 * enable the VCPU interface
192 * @vcpu: the VCPU which's VGIC should be initialized
193 */
194static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
195{
196 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
197 int i;
198
199 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
200 spin_lock_init(&vgic_cpu->ap_list_lock);
201
202 /*
203 * Enable and configure all SGIs to be edge-triggered and
204 * configure all PPIs as level-triggered.
205 */
206 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
207 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
208
209 INIT_LIST_HEAD(&irq->ap_list);
210 spin_lock_init(&irq->irq_lock);
211 irq->intid = i;
212 irq->vcpu = NULL;
213 irq->target_vcpu = vcpu;
214 irq->targets = 1U << vcpu->vcpu_id;
5dd4b924 215 kref_init(&irq->refcount);
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216 if (vgic_irq_is_sgi(i)) {
217 /* SGIs */
218 irq->enabled = 1;
219 irq->config = VGIC_CONFIG_EDGE;
220 } else {
221 /* PPIs */
222 irq->config = VGIC_CONFIG_LEVEL;
223 }
224 }
225 if (kvm_vgic_global_state.type == VGIC_V2)
226 vgic_v2_enable(vcpu);
227 else
228 vgic_v3_enable(vcpu);
229}
230
231/*
232 * vgic_init: allocates and initializes dist and vcpu data structures
233 * depending on two dimensioning parameters:
234 * - the number of spis
235 * - the number of vcpus
236 * The function is generally called when nr_spis has been explicitly set
237 * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
238 * vgic_initialized() returns true when this function has succeeded.
239 * Must be called with kvm->lock held!
240 */
241int vgic_init(struct kvm *kvm)
242{
243 struct vgic_dist *dist = &kvm->arch.vgic;
244 struct kvm_vcpu *vcpu;
245 int ret = 0, i;
246
247 if (vgic_initialized(kvm))
248 return 0;
249
250 /* freeze the number of spis */
251 if (!dist->nr_spis)
252 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
253
254 ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
255 if (ret)
256 goto out;
257
258 kvm_for_each_vcpu(i, vcpu, kvm)
259 kvm_vgic_vcpu_init(vcpu);
260
261 dist->initialized = true;
262out:
263 return ret;
264}
265
266static void kvm_vgic_dist_destroy(struct kvm *kvm)
267{
268 struct vgic_dist *dist = &kvm->arch.vgic;
269
270 mutex_lock(&kvm->lock);
271
272 dist->ready = false;
273 dist->initialized = false;
274
275 kfree(dist->spis);
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276 dist->nr_spis = 0;
277
278 mutex_unlock(&kvm->lock);
279}
280
281void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
282{
283 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
284
285 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
286}
287
288void kvm_vgic_destroy(struct kvm *kvm)
289{
290 struct kvm_vcpu *vcpu;
291 int i;
292
293 kvm_vgic_dist_destroy(kvm);
294
295 kvm_for_each_vcpu(i, vcpu, kvm)
296 kvm_vgic_vcpu_destroy(vcpu);
297}
298
299/**
300 * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
301 * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
302 * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
303 * @kvm: kvm struct pointer
304 */
305int vgic_lazy_init(struct kvm *kvm)
306{
307 int ret = 0;
308
309 if (unlikely(!vgic_initialized(kvm))) {
310 /*
311 * We only provide the automatic initialization of the VGIC
312 * for the legacy case of a GICv2. Any other type must
313 * be explicitly initialized once setup with the respective
314 * KVM device call.
315 */
316 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
317 return -EBUSY;
318
319 mutex_lock(&kvm->lock);
320 ret = vgic_init(kvm);
321 mutex_unlock(&kvm->lock);
322 }
323
324 return ret;
325}
326
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327/* RESOURCE MAPPING */
328
329/**
330 * Map the MMIO regions depending on the VGIC model exposed to the guest
331 * called on the first VCPU run.
332 * Also map the virtual CPU interface into the VM.
333 * v2/v3 derivatives call vgic_init if not already done.
334 * vgic_ready() returns true if this function has succeeded.
335 * @kvm: kvm struct pointer
336 */
337int kvm_vgic_map_resources(struct kvm *kvm)
338{
339 struct vgic_dist *dist = &kvm->arch.vgic;
340 int ret = 0;
341
342 mutex_lock(&kvm->lock);
343 if (!irqchip_in_kernel(kvm))
344 goto out;
345
346 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
347 ret = vgic_v2_map_resources(kvm);
348 else
349 ret = vgic_v3_map_resources(kvm);
350out:
351 mutex_unlock(&kvm->lock);
352 return ret;
353}
354
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355/* GENERIC PROBE */
356
357static void vgic_init_maintenance_interrupt(void *info)
358{
359 enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
360}
361
362static int vgic_cpu_notify(struct notifier_block *self,
363 unsigned long action, void *cpu)
364{
365 switch (action) {
366 case CPU_STARTING:
367 case CPU_STARTING_FROZEN:
368 vgic_init_maintenance_interrupt(NULL);
369 break;
370 case CPU_DYING:
371 case CPU_DYING_FROZEN:
372 disable_percpu_irq(kvm_vgic_global_state.maint_irq);
373 break;
374 }
375
376 return NOTIFY_OK;
377}
378
379static struct notifier_block vgic_cpu_nb = {
380 .notifier_call = vgic_cpu_notify,
381};
382
383static irqreturn_t vgic_maintenance_handler(int irq, void *data)
384{
385 /*
386 * We cannot rely on the vgic maintenance interrupt to be
387 * delivered synchronously. This means we can only use it to
388 * exit the VM, and we perform the handling of EOIed
389 * interrupts on the exit path (see vgic_process_maintenance).
390 */
391 return IRQ_HANDLED;
392}
393
394/**
395 * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
396 * according to the host GIC model. Accordingly calls either
397 * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
398 * instantiated by a guest later on .
399 */
400int kvm_vgic_hyp_init(void)
401{
402 const struct gic_kvm_info *gic_kvm_info;
403 int ret;
404
405 gic_kvm_info = gic_get_kvm_info();
406 if (!gic_kvm_info)
407 return -ENODEV;
408
409 if (!gic_kvm_info->maint_irq) {
410 kvm_err("No vgic maintenance irq\n");
411 return -ENXIO;
412 }
413
414 switch (gic_kvm_info->type) {
415 case GIC_V2:
416 ret = vgic_v2_probe(gic_kvm_info);
417 break;
418 case GIC_V3:
419 ret = vgic_v3_probe(gic_kvm_info);
420 break;
421 default:
422 ret = -ENODEV;
423 };
424
425 if (ret)
426 return ret;
427
428 kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
429 ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
430 vgic_maintenance_handler,
431 "vgic", kvm_get_running_vcpus());
432 if (ret) {
433 kvm_err("Cannot register interrupt %d\n",
434 kvm_vgic_global_state.maint_irq);
435 return ret;
436 }
437
438 ret = __register_cpu_notifier(&vgic_cpu_nb);
439 if (ret) {
440 kvm_err("Cannot register vgic CPU notifier\n");
441 goto out_free_irq;
442 }
443
444 on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
445
446 kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
447 return 0;
448
449out_free_irq:
450 free_percpu_irq(kvm_vgic_global_state.maint_irq,
451 kvm_get_running_vcpus());
452 return ret;
453}