KVM: Protect device ops->create and list_add with kvm->lock
[deliverable/linux.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
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76 if (irqchip_in_kernel(kvm))
77 return -EEXIST;
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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 &&
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86 !kvm_vgic_global_state.can_emulate_gicv2)
87 return -ENODEV;
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88
89 /*
90 * Any time a vcpu is run, vcpu_load is called which tries to grab the
91 * vcpu->mutex. By grabbing the vcpu->mutex of all VCPUs we ensure
92 * that no other VCPUs are run while we create the vgic.
93 */
94 ret = -EBUSY;
95 kvm_for_each_vcpu(i, vcpu, kvm) {
96 if (!mutex_trylock(&vcpu->mutex))
97 goto out_unlock;
98 vcpu_lock_idx = i;
99 }
100
101 kvm_for_each_vcpu(i, vcpu, kvm) {
102 if (vcpu->arch.has_run_once)
103 goto out_unlock;
104 }
105 ret = 0;
106
107 if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
108 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
109 else
110 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
111
112 if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
113 ret = -E2BIG;
114 goto out_unlock;
115 }
116
117 kvm->arch.vgic.in_kernel = true;
118 kvm->arch.vgic.vgic_model = type;
119
120 /*
121 * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
122 * it is stored in distributor struct for asm save/restore purpose
123 */
124 kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
125
126 kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
127 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
128 kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
129
130out_unlock:
131 for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
132 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
133 mutex_unlock(&vcpu->mutex);
134 }
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135 return ret;
136}
137
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138/* INIT/DESTROY */
139
140/**
141 * kvm_vgic_dist_init: initialize the dist data structures
142 * @kvm: kvm struct pointer
143 * @nr_spis: number of spis, frozen by caller
144 */
145static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
146{
147 struct vgic_dist *dist = &kvm->arch.vgic;
148 struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
149 int i;
150
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151 INIT_LIST_HEAD(&dist->lpi_list_head);
152 spin_lock_init(&dist->lpi_list_lock);
153
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154 dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
155 if (!dist->spis)
156 return -ENOMEM;
157
158 /*
159 * In the following code we do not take the irq struct lock since
160 * no other action on irq structs can happen while the VGIC is
161 * not initialized yet:
162 * If someone wants to inject an interrupt or does a MMIO access, we
163 * require prior initialization in case of a virtual GICv3 or trigger
164 * initialization when using a virtual GICv2.
165 */
166 for (i = 0; i < nr_spis; i++) {
167 struct vgic_irq *irq = &dist->spis[i];
168
169 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
170 INIT_LIST_HEAD(&irq->ap_list);
171 spin_lock_init(&irq->irq_lock);
172 irq->vcpu = NULL;
173 irq->target_vcpu = vcpu0;
5dd4b924 174 kref_init(&irq->refcount);
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175 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
176 irq->targets = 0;
177 else
178 irq->mpidr = 0;
179 }
180 return 0;
181}
182
183/**
184 * kvm_vgic_vcpu_init: initialize the vcpu data structures and
185 * enable the VCPU interface
186 * @vcpu: the VCPU which's VGIC should be initialized
187 */
188static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
189{
190 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
191 int i;
192
193 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
194 spin_lock_init(&vgic_cpu->ap_list_lock);
195
196 /*
197 * Enable and configure all SGIs to be edge-triggered and
198 * configure all PPIs as level-triggered.
199 */
200 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
201 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
202
203 INIT_LIST_HEAD(&irq->ap_list);
204 spin_lock_init(&irq->irq_lock);
205 irq->intid = i;
206 irq->vcpu = NULL;
207 irq->target_vcpu = vcpu;
208 irq->targets = 1U << vcpu->vcpu_id;
5dd4b924 209 kref_init(&irq->refcount);
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210 if (vgic_irq_is_sgi(i)) {
211 /* SGIs */
212 irq->enabled = 1;
213 irq->config = VGIC_CONFIG_EDGE;
214 } else {
215 /* PPIs */
216 irq->config = VGIC_CONFIG_LEVEL;
217 }
218 }
219 if (kvm_vgic_global_state.type == VGIC_V2)
220 vgic_v2_enable(vcpu);
221 else
222 vgic_v3_enable(vcpu);
223}
224
225/*
226 * vgic_init: allocates and initializes dist and vcpu data structures
227 * depending on two dimensioning parameters:
228 * - the number of spis
229 * - the number of vcpus
230 * The function is generally called when nr_spis has been explicitly set
231 * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
232 * vgic_initialized() returns true when this function has succeeded.
233 * Must be called with kvm->lock held!
234 */
235int vgic_init(struct kvm *kvm)
236{
237 struct vgic_dist *dist = &kvm->arch.vgic;
238 struct kvm_vcpu *vcpu;
239 int ret = 0, i;
240
241 if (vgic_initialized(kvm))
242 return 0;
243
244 /* freeze the number of spis */
245 if (!dist->nr_spis)
246 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
247
248 ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
249 if (ret)
250 goto out;
251
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252 if (vgic_has_its(kvm))
253 dist->msis_require_devid = true;
254
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255 kvm_for_each_vcpu(i, vcpu, kvm)
256 kvm_vgic_vcpu_init(vcpu);
257
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258 ret = kvm_vgic_setup_default_irq_routing(kvm);
259 if (ret)
260 goto out;
261
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262 dist->initialized = true;
263out:
264 return ret;
265}
266
267static void kvm_vgic_dist_destroy(struct kvm *kvm)
268{
269 struct vgic_dist *dist = &kvm->arch.vgic;
270
271 mutex_lock(&kvm->lock);
272
273 dist->ready = false;
274 dist->initialized = false;
275
276 kfree(dist->spis);
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277 dist->nr_spis = 0;
278
279 mutex_unlock(&kvm->lock);
280}
281
282void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
283{
284 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
285
286 INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
287}
288
289void kvm_vgic_destroy(struct kvm *kvm)
290{
291 struct kvm_vcpu *vcpu;
292 int i;
293
294 kvm_vgic_dist_destroy(kvm);
295
296 kvm_for_each_vcpu(i, vcpu, kvm)
297 kvm_vgic_vcpu_destroy(vcpu);
298}
299
300/**
301 * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
302 * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
303 * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
304 * @kvm: kvm struct pointer
305 */
306int vgic_lazy_init(struct kvm *kvm)
307{
308 int ret = 0;
309
310 if (unlikely(!vgic_initialized(kvm))) {
311 /*
312 * We only provide the automatic initialization of the VGIC
313 * for the legacy case of a GICv2. Any other type must
314 * be explicitly initialized once setup with the respective
315 * KVM device call.
316 */
317 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
318 return -EBUSY;
319
320 mutex_lock(&kvm->lock);
321 ret = vgic_init(kvm);
322 mutex_unlock(&kvm->lock);
323 }
324
325 return ret;
326}
327
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328/* RESOURCE MAPPING */
329
330/**
331 * Map the MMIO regions depending on the VGIC model exposed to the guest
332 * called on the first VCPU run.
333 * Also map the virtual CPU interface into the VM.
334 * v2/v3 derivatives call vgic_init if not already done.
335 * vgic_ready() returns true if this function has succeeded.
336 * @kvm: kvm struct pointer
337 */
338int kvm_vgic_map_resources(struct kvm *kvm)
339{
340 struct vgic_dist *dist = &kvm->arch.vgic;
341 int ret = 0;
342
343 mutex_lock(&kvm->lock);
344 if (!irqchip_in_kernel(kvm))
345 goto out;
346
347 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
348 ret = vgic_v2_map_resources(kvm);
349 else
350 ret = vgic_v3_map_resources(kvm);
351out:
352 mutex_unlock(&kvm->lock);
353 return ret;
354}
355
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356/* GENERIC PROBE */
357
15d7e3d3 358static int vgic_init_cpu_starting(unsigned int cpu)
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359{
360 enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
15d7e3d3 361 return 0;
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362}
363
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365static int vgic_init_cpu_dying(unsigned int cpu)
366{
367 disable_percpu_irq(kvm_vgic_global_state.maint_irq);
368 return 0;
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369}
370
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371static irqreturn_t vgic_maintenance_handler(int irq, void *data)
372{
373 /*
374 * We cannot rely on the vgic maintenance interrupt to be
375 * delivered synchronously. This means we can only use it to
376 * exit the VM, and we perform the handling of EOIed
377 * interrupts on the exit path (see vgic_process_maintenance).
378 */
379 return IRQ_HANDLED;
380}
381
382/**
383 * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
384 * according to the host GIC model. Accordingly calls either
385 * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
386 * instantiated by a guest later on .
387 */
388int kvm_vgic_hyp_init(void)
389{
390 const struct gic_kvm_info *gic_kvm_info;
391 int ret;
392
393 gic_kvm_info = gic_get_kvm_info();
394 if (!gic_kvm_info)
395 return -ENODEV;
396
397 if (!gic_kvm_info->maint_irq) {
398 kvm_err("No vgic maintenance irq\n");
399 return -ENXIO;
400 }
401
402 switch (gic_kvm_info->type) {
403 case GIC_V2:
404 ret = vgic_v2_probe(gic_kvm_info);
405 break;
406 case GIC_V3:
407 ret = vgic_v3_probe(gic_kvm_info);
408 break;
409 default:
410 ret = -ENODEV;
411 };
412
413 if (ret)
414 return ret;
415
416 kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
417 ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
418 vgic_maintenance_handler,
419 "vgic", kvm_get_running_vcpus());
420 if (ret) {
421 kvm_err("Cannot register interrupt %d\n",
422 kvm_vgic_global_state.maint_irq);
423 return ret;
424 }
425
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426 ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
427 "AP_KVM_ARM_VGIC_INIT_STARTING",
428 vgic_init_cpu_starting, vgic_init_cpu_dying);
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429 if (ret) {
430 kvm_err("Cannot register vgic CPU notifier\n");
431 goto out_free_irq;
432 }
433
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434 kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
435 return 0;
436
437out_free_irq:
438 free_percpu_irq(kvm_vgic_global_state.maint_irq,
439 kvm_get_running_vcpus());
440 return ret;
441}
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