xref: /openbmc/linux/arch/arm64/kvm/vgic/vgic-v2.c (revision b3b984dc)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2015, 2016 ARM Ltd.
4  */
5 
6 #include <linux/irqchip/arm-gic.h>
7 #include <linux/kvm.h>
8 #include <linux/kvm_host.h>
9 #include <kvm/arm_vgic.h>
10 #include <asm/kvm_mmu.h>
11 
12 #include "vgic.h"
13 
14 static inline void vgic_v2_write_lr(int lr, u32 val)
15 {
16 	void __iomem *base = kvm_vgic_global_state.vctrl_base;
17 
18 	writel_relaxed(val, base + GICH_LR0 + (lr * 4));
19 }
20 
21 void vgic_v2_init_lrs(void)
22 {
23 	int i;
24 
25 	for (i = 0; i < kvm_vgic_global_state.nr_lr; i++)
26 		vgic_v2_write_lr(i, 0);
27 }
28 
29 void vgic_v2_set_underflow(struct kvm_vcpu *vcpu)
30 {
31 	struct vgic_v2_cpu_if *cpuif = &vcpu->arch.vgic_cpu.vgic_v2;
32 
33 	cpuif->vgic_hcr |= GICH_HCR_UIE;
34 }
35 
36 static bool lr_signals_eoi_mi(u32 lr_val)
37 {
38 	return !(lr_val & GICH_LR_STATE) && (lr_val & GICH_LR_EOI) &&
39 	       !(lr_val & GICH_LR_HW);
40 }
41 
42 /*
43  * transfer the content of the LRs back into the corresponding ap_list:
44  * - active bit is transferred as is
45  * - pending bit is
46  *   - transferred as is in case of edge sensitive IRQs
47  *   - set to the line-level (resample time) for level sensitive IRQs
48  */
49 void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
50 {
51 	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
52 	struct vgic_v2_cpu_if *cpuif = &vgic_cpu->vgic_v2;
53 	int lr;
54 
55 	DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
56 
57 	cpuif->vgic_hcr &= ~GICH_HCR_UIE;
58 
59 	for (lr = 0; lr < vgic_cpu->vgic_v2.used_lrs; lr++) {
60 		u32 val = cpuif->vgic_lr[lr];
61 		u32 cpuid, intid = val & GICH_LR_VIRTUALID;
62 		struct vgic_irq *irq;
63 		bool deactivated;
64 
65 		/* Extract the source vCPU id from the LR */
66 		cpuid = val & GICH_LR_PHYSID_CPUID;
67 		cpuid >>= GICH_LR_PHYSID_CPUID_SHIFT;
68 		cpuid &= 7;
69 
70 		/* Notify fds when the guest EOI'ed a level-triggered SPI */
71 		if (lr_signals_eoi_mi(val) && vgic_valid_spi(vcpu->kvm, intid))
72 			kvm_notify_acked_irq(vcpu->kvm, 0,
73 					     intid - VGIC_NR_PRIVATE_IRQS);
74 
75 		irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
76 
77 		raw_spin_lock(&irq->irq_lock);
78 
79 		/* Always preserve the active bit, note deactivation */
80 		deactivated = irq->active && !(val & GICH_LR_ACTIVE_BIT);
81 		irq->active = !!(val & GICH_LR_ACTIVE_BIT);
82 
83 		if (irq->active && vgic_irq_is_sgi(intid))
84 			irq->active_source = cpuid;
85 
86 		/* Edge is the only case where we preserve the pending bit */
87 		if (irq->config == VGIC_CONFIG_EDGE &&
88 		    (val & GICH_LR_PENDING_BIT)) {
89 			irq->pending_latch = true;
90 
91 			if (vgic_irq_is_sgi(intid))
92 				irq->source |= (1 << cpuid);
93 		}
94 
95 		/*
96 		 * Clear soft pending state when level irqs have been acked.
97 		 */
98 		if (irq->config == VGIC_CONFIG_LEVEL && !(val & GICH_LR_STATE))
99 			irq->pending_latch = false;
100 
101 		/* Handle resampling for mapped interrupts if required */
102 		vgic_irq_handle_resampling(irq, deactivated, val & GICH_LR_PENDING_BIT);
103 
104 		raw_spin_unlock(&irq->irq_lock);
105 		vgic_put_irq(vcpu->kvm, irq);
106 	}
107 
108 	cpuif->used_lrs = 0;
109 }
110 
111 /*
112  * Populates the particular LR with the state of a given IRQ:
113  * - for an edge sensitive IRQ the pending state is cleared in struct vgic_irq
114  * - for a level sensitive IRQ the pending state value is unchanged;
115  *   it is dictated directly by the input level
116  *
117  * If @irq describes an SGI with multiple sources, we choose the
118  * lowest-numbered source VCPU and clear that bit in the source bitmap.
119  *
120  * The irq_lock must be held by the caller.
121  */
122 void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
123 {
124 	u32 val = irq->intid;
125 	bool allow_pending = true;
126 
127 	if (irq->active) {
128 		val |= GICH_LR_ACTIVE_BIT;
129 		if (vgic_irq_is_sgi(irq->intid))
130 			val |= irq->active_source << GICH_LR_PHYSID_CPUID_SHIFT;
131 		if (vgic_irq_is_multi_sgi(irq)) {
132 			allow_pending = false;
133 			val |= GICH_LR_EOI;
134 		}
135 	}
136 
137 	if (irq->group)
138 		val |= GICH_LR_GROUP1;
139 
140 	if (irq->hw && !vgic_irq_needs_resampling(irq)) {
141 		val |= GICH_LR_HW;
142 		val |= irq->hwintid << GICH_LR_PHYSID_CPUID_SHIFT;
143 		/*
144 		 * Never set pending+active on a HW interrupt, as the
145 		 * pending state is kept at the physical distributor
146 		 * level.
147 		 */
148 		if (irq->active)
149 			allow_pending = false;
150 	} else {
151 		if (irq->config == VGIC_CONFIG_LEVEL) {
152 			val |= GICH_LR_EOI;
153 
154 			/*
155 			 * Software resampling doesn't work very well
156 			 * if we allow P+A, so let's not do that.
157 			 */
158 			if (irq->active)
159 				allow_pending = false;
160 		}
161 	}
162 
163 	if (allow_pending && irq_is_pending(irq)) {
164 		val |= GICH_LR_PENDING_BIT;
165 
166 		if (irq->config == VGIC_CONFIG_EDGE)
167 			irq->pending_latch = false;
168 
169 		if (vgic_irq_is_sgi(irq->intid)) {
170 			u32 src = ffs(irq->source);
171 
172 			if (WARN_RATELIMIT(!src, "No SGI source for INTID %d\n",
173 					   irq->intid))
174 				return;
175 
176 			val |= (src - 1) << GICH_LR_PHYSID_CPUID_SHIFT;
177 			irq->source &= ~(1 << (src - 1));
178 			if (irq->source) {
179 				irq->pending_latch = true;
180 				val |= GICH_LR_EOI;
181 			}
182 		}
183 	}
184 
185 	/*
186 	 * Level-triggered mapped IRQs are special because we only observe
187 	 * rising edges as input to the VGIC.  We therefore lower the line
188 	 * level here, so that we can take new virtual IRQs.  See
189 	 * vgic_v2_fold_lr_state for more info.
190 	 */
191 	if (vgic_irq_is_mapped_level(irq) && (val & GICH_LR_PENDING_BIT))
192 		irq->line_level = false;
193 
194 	/* The GICv2 LR only holds five bits of priority. */
195 	val |= (irq->priority >> 3) << GICH_LR_PRIORITY_SHIFT;
196 
197 	vcpu->arch.vgic_cpu.vgic_v2.vgic_lr[lr] = val;
198 }
199 
200 void vgic_v2_clear_lr(struct kvm_vcpu *vcpu, int lr)
201 {
202 	vcpu->arch.vgic_cpu.vgic_v2.vgic_lr[lr] = 0;
203 }
204 
205 void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
206 {
207 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
208 	u32 vmcr;
209 
210 	vmcr = (vmcrp->grpen0 << GICH_VMCR_ENABLE_GRP0_SHIFT) &
211 		GICH_VMCR_ENABLE_GRP0_MASK;
212 	vmcr |= (vmcrp->grpen1 << GICH_VMCR_ENABLE_GRP1_SHIFT) &
213 		GICH_VMCR_ENABLE_GRP1_MASK;
214 	vmcr |= (vmcrp->ackctl << GICH_VMCR_ACK_CTL_SHIFT) &
215 		GICH_VMCR_ACK_CTL_MASK;
216 	vmcr |= (vmcrp->fiqen << GICH_VMCR_FIQ_EN_SHIFT) &
217 		GICH_VMCR_FIQ_EN_MASK;
218 	vmcr |= (vmcrp->cbpr << GICH_VMCR_CBPR_SHIFT) &
219 		GICH_VMCR_CBPR_MASK;
220 	vmcr |= (vmcrp->eoim << GICH_VMCR_EOI_MODE_SHIFT) &
221 		GICH_VMCR_EOI_MODE_MASK;
222 	vmcr |= (vmcrp->abpr << GICH_VMCR_ALIAS_BINPOINT_SHIFT) &
223 		GICH_VMCR_ALIAS_BINPOINT_MASK;
224 	vmcr |= (vmcrp->bpr << GICH_VMCR_BINPOINT_SHIFT) &
225 		GICH_VMCR_BINPOINT_MASK;
226 	vmcr |= ((vmcrp->pmr >> GICV_PMR_PRIORITY_SHIFT) <<
227 		 GICH_VMCR_PRIMASK_SHIFT) & GICH_VMCR_PRIMASK_MASK;
228 
229 	cpu_if->vgic_vmcr = vmcr;
230 }
231 
232 void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
233 {
234 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
235 	u32 vmcr;
236 
237 	vmcr = cpu_if->vgic_vmcr;
238 
239 	vmcrp->grpen0 = (vmcr & GICH_VMCR_ENABLE_GRP0_MASK) >>
240 		GICH_VMCR_ENABLE_GRP0_SHIFT;
241 	vmcrp->grpen1 = (vmcr & GICH_VMCR_ENABLE_GRP1_MASK) >>
242 		GICH_VMCR_ENABLE_GRP1_SHIFT;
243 	vmcrp->ackctl = (vmcr & GICH_VMCR_ACK_CTL_MASK) >>
244 		GICH_VMCR_ACK_CTL_SHIFT;
245 	vmcrp->fiqen = (vmcr & GICH_VMCR_FIQ_EN_MASK) >>
246 		GICH_VMCR_FIQ_EN_SHIFT;
247 	vmcrp->cbpr = (vmcr & GICH_VMCR_CBPR_MASK) >>
248 		GICH_VMCR_CBPR_SHIFT;
249 	vmcrp->eoim = (vmcr & GICH_VMCR_EOI_MODE_MASK) >>
250 		GICH_VMCR_EOI_MODE_SHIFT;
251 
252 	vmcrp->abpr = (vmcr & GICH_VMCR_ALIAS_BINPOINT_MASK) >>
253 			GICH_VMCR_ALIAS_BINPOINT_SHIFT;
254 	vmcrp->bpr  = (vmcr & GICH_VMCR_BINPOINT_MASK) >>
255 			GICH_VMCR_BINPOINT_SHIFT;
256 	vmcrp->pmr  = ((vmcr & GICH_VMCR_PRIMASK_MASK) >>
257 			GICH_VMCR_PRIMASK_SHIFT) << GICV_PMR_PRIORITY_SHIFT;
258 }
259 
260 void vgic_v2_enable(struct kvm_vcpu *vcpu)
261 {
262 	/*
263 	 * By forcing VMCR to zero, the GIC will restore the binary
264 	 * points to their reset values. Anything else resets to zero
265 	 * anyway.
266 	 */
267 	vcpu->arch.vgic_cpu.vgic_v2.vgic_vmcr = 0;
268 
269 	/* Get the show on the road... */
270 	vcpu->arch.vgic_cpu.vgic_v2.vgic_hcr = GICH_HCR_EN;
271 }
272 
273 /* check for overlapping regions and for regions crossing the end of memory */
274 static bool vgic_v2_check_base(gpa_t dist_base, gpa_t cpu_base)
275 {
276 	if (dist_base + KVM_VGIC_V2_DIST_SIZE < dist_base)
277 		return false;
278 	if (cpu_base + KVM_VGIC_V2_CPU_SIZE < cpu_base)
279 		return false;
280 
281 	if (dist_base + KVM_VGIC_V2_DIST_SIZE <= cpu_base)
282 		return true;
283 	if (cpu_base + KVM_VGIC_V2_CPU_SIZE <= dist_base)
284 		return true;
285 
286 	return false;
287 }
288 
289 int vgic_v2_map_resources(struct kvm *kvm)
290 {
291 	struct vgic_dist *dist = &kvm->arch.vgic;
292 	int ret = 0;
293 
294 	if (IS_VGIC_ADDR_UNDEF(dist->vgic_dist_base) ||
295 	    IS_VGIC_ADDR_UNDEF(dist->vgic_cpu_base)) {
296 		kvm_debug("Need to set vgic cpu and dist addresses first\n");
297 		return -ENXIO;
298 	}
299 
300 	if (!vgic_v2_check_base(dist->vgic_dist_base, dist->vgic_cpu_base)) {
301 		kvm_debug("VGIC CPU and dist frames overlap\n");
302 		return -EINVAL;
303 	}
304 
305 	/*
306 	 * Initialize the vgic if this hasn't already been done on demand by
307 	 * accessing the vgic state from userspace.
308 	 */
309 	ret = vgic_init(kvm);
310 	if (ret) {
311 		kvm_err("Unable to initialize VGIC dynamic data structures\n");
312 		return ret;
313 	}
314 
315 	if (!static_branch_unlikely(&vgic_v2_cpuif_trap)) {
316 		ret = kvm_phys_addr_ioremap(kvm, dist->vgic_cpu_base,
317 					    kvm_vgic_global_state.vcpu_base,
318 					    KVM_VGIC_V2_CPU_SIZE, true);
319 		if (ret) {
320 			kvm_err("Unable to remap VGIC CPU to VCPU\n");
321 			return ret;
322 		}
323 	}
324 
325 	return 0;
326 }
327 
328 DEFINE_STATIC_KEY_FALSE(vgic_v2_cpuif_trap);
329 
330 /**
331  * vgic_v2_probe - probe for a VGICv2 compatible interrupt controller
332  * @info:	pointer to the GIC description
333  *
334  * Returns 0 if the VGICv2 has been probed successfully, returns an error code
335  * otherwise
336  */
337 int vgic_v2_probe(const struct gic_kvm_info *info)
338 {
339 	int ret;
340 	u32 vtr;
341 
342 	if (is_protected_kvm_enabled()) {
343 		kvm_err("GICv2 not supported in protected mode\n");
344 		return -ENXIO;
345 	}
346 
347 	if (!info->vctrl.start) {
348 		kvm_err("GICH not present in the firmware table\n");
349 		return -ENXIO;
350 	}
351 
352 	if (!PAGE_ALIGNED(info->vcpu.start) ||
353 	    !PAGE_ALIGNED(resource_size(&info->vcpu))) {
354 		kvm_info("GICV region size/alignment is unsafe, using trapping (reduced performance)\n");
355 
356 		ret = create_hyp_io_mappings(info->vcpu.start,
357 					     resource_size(&info->vcpu),
358 					     &kvm_vgic_global_state.vcpu_base_va,
359 					     &kvm_vgic_global_state.vcpu_hyp_va);
360 		if (ret) {
361 			kvm_err("Cannot map GICV into hyp\n");
362 			goto out;
363 		}
364 
365 		static_branch_enable(&vgic_v2_cpuif_trap);
366 	}
367 
368 	ret = create_hyp_io_mappings(info->vctrl.start,
369 				     resource_size(&info->vctrl),
370 				     &kvm_vgic_global_state.vctrl_base,
371 				     &kvm_vgic_global_state.vctrl_hyp);
372 	if (ret) {
373 		kvm_err("Cannot map VCTRL into hyp\n");
374 		goto out;
375 	}
376 
377 	vtr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_VTR);
378 	kvm_vgic_global_state.nr_lr = (vtr & 0x3f) + 1;
379 
380 	ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
381 	if (ret) {
382 		kvm_err("Cannot register GICv2 KVM device\n");
383 		goto out;
384 	}
385 
386 	kvm_vgic_global_state.can_emulate_gicv2 = true;
387 	kvm_vgic_global_state.vcpu_base = info->vcpu.start;
388 	kvm_vgic_global_state.type = VGIC_V2;
389 	kvm_vgic_global_state.max_gic_vcpus = VGIC_V2_MAX_CPUS;
390 
391 	kvm_debug("vgic-v2@%llx\n", info->vctrl.start);
392 
393 	return 0;
394 out:
395 	if (kvm_vgic_global_state.vctrl_base)
396 		iounmap(kvm_vgic_global_state.vctrl_base);
397 	if (kvm_vgic_global_state.vcpu_base_va)
398 		iounmap(kvm_vgic_global_state.vcpu_base_va);
399 
400 	return ret;
401 }
402 
403 static void save_lrs(struct kvm_vcpu *vcpu, void __iomem *base)
404 {
405 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
406 	u64 used_lrs = cpu_if->used_lrs;
407 	u64 elrsr;
408 	int i;
409 
410 	elrsr = readl_relaxed(base + GICH_ELRSR0);
411 	if (unlikely(used_lrs > 32))
412 		elrsr |= ((u64)readl_relaxed(base + GICH_ELRSR1)) << 32;
413 
414 	for (i = 0; i < used_lrs; i++) {
415 		if (elrsr & (1UL << i))
416 			cpu_if->vgic_lr[i] &= ~GICH_LR_STATE;
417 		else
418 			cpu_if->vgic_lr[i] = readl_relaxed(base + GICH_LR0 + (i * 4));
419 
420 		writel_relaxed(0, base + GICH_LR0 + (i * 4));
421 	}
422 }
423 
424 void vgic_v2_save_state(struct kvm_vcpu *vcpu)
425 {
426 	void __iomem *base = kvm_vgic_global_state.vctrl_base;
427 	u64 used_lrs = vcpu->arch.vgic_cpu.vgic_v2.used_lrs;
428 
429 	if (!base)
430 		return;
431 
432 	if (used_lrs) {
433 		save_lrs(vcpu, base);
434 		writel_relaxed(0, base + GICH_HCR);
435 	}
436 }
437 
438 void vgic_v2_restore_state(struct kvm_vcpu *vcpu)
439 {
440 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
441 	void __iomem *base = kvm_vgic_global_state.vctrl_base;
442 	u64 used_lrs = cpu_if->used_lrs;
443 	int i;
444 
445 	if (!base)
446 		return;
447 
448 	if (used_lrs) {
449 		writel_relaxed(cpu_if->vgic_hcr, base + GICH_HCR);
450 		for (i = 0; i < used_lrs; i++) {
451 			writel_relaxed(cpu_if->vgic_lr[i],
452 				       base + GICH_LR0 + (i * 4));
453 		}
454 	}
455 }
456 
457 void vgic_v2_load(struct kvm_vcpu *vcpu)
458 {
459 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
460 
461 	writel_relaxed(cpu_if->vgic_vmcr,
462 		       kvm_vgic_global_state.vctrl_base + GICH_VMCR);
463 	writel_relaxed(cpu_if->vgic_apr,
464 		       kvm_vgic_global_state.vctrl_base + GICH_APR);
465 }
466 
467 void vgic_v2_vmcr_sync(struct kvm_vcpu *vcpu)
468 {
469 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
470 
471 	cpu_if->vgic_vmcr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_VMCR);
472 }
473 
474 void vgic_v2_put(struct kvm_vcpu *vcpu)
475 {
476 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
477 
478 	vgic_v2_vmcr_sync(vcpu);
479 	cpu_if->vgic_apr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_APR);
480 }
481