xref: /openbmc/linux/virt/kvm/irqchip.c (revision 2a598d0b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * irqchip.c: Common API for in kernel interrupt controllers
4  * Copyright (c) 2007, Intel Corporation.
5  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
6  * Copyright (c) 2013, Alexander Graf <agraf@suse.de>
7  *
8  * This file is derived from virt/kvm/irq_comm.c.
9  *
10  * Authors:
11  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
12  *   Alexander Graf <agraf@suse.de>
13  */
14 
15 #include <linux/kvm_host.h>
16 #include <linux/slab.h>
17 #include <linux/srcu.h>
18 #include <linux/export.h>
19 #include <trace/events/kvm.h>
20 
21 int kvm_irq_map_gsi(struct kvm *kvm,
22 		    struct kvm_kernel_irq_routing_entry *entries, int gsi)
23 {
24 	struct kvm_irq_routing_table *irq_rt;
25 	struct kvm_kernel_irq_routing_entry *e;
26 	int n = 0;
27 
28 	irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
29 					lockdep_is_held(&kvm->irq_lock));
30 	if (irq_rt && gsi < irq_rt->nr_rt_entries) {
31 		hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
32 			entries[n] = *e;
33 			++n;
34 		}
35 	}
36 
37 	return n;
38 }
39 
40 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
41 {
42 	struct kvm_irq_routing_table *irq_rt;
43 
44 	irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
45 	return irq_rt->chip[irqchip][pin];
46 }
47 
48 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
49 {
50 	struct kvm_kernel_irq_routing_entry route;
51 
52 	if (!kvm_arch_irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
53 		return -EINVAL;
54 
55 	route.msi.address_lo = msi->address_lo;
56 	route.msi.address_hi = msi->address_hi;
57 	route.msi.data = msi->data;
58 	route.msi.flags = msi->flags;
59 	route.msi.devid = msi->devid;
60 
61 	return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
62 }
63 
64 /*
65  * Return value:
66  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
67  *  = 0   Interrupt was coalesced (previous irq is still pending)
68  *  > 0   Number of CPUs interrupt was delivered to
69  */
70 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
71 		bool line_status)
72 {
73 	struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
74 	int ret = -1, i, idx;
75 
76 	trace_kvm_set_irq(irq, level, irq_source_id);
77 
78 	/* Not possible to detect if the guest uses the PIC or the
79 	 * IOAPIC.  So set the bit in both. The guest will ignore
80 	 * writes to the unused one.
81 	 */
82 	idx = srcu_read_lock(&kvm->irq_srcu);
83 	i = kvm_irq_map_gsi(kvm, irq_set, irq);
84 	srcu_read_unlock(&kvm->irq_srcu, idx);
85 
86 	while (i--) {
87 		int r;
88 		r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
89 				   line_status);
90 		if (r < 0)
91 			continue;
92 
93 		ret = r + ((ret < 0) ? 0 : ret);
94 	}
95 
96 	return ret;
97 }
98 
99 static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
100 {
101 	int i;
102 
103 	if (!rt)
104 		return;
105 
106 	for (i = 0; i < rt->nr_rt_entries; ++i) {
107 		struct kvm_kernel_irq_routing_entry *e;
108 		struct hlist_node *n;
109 
110 		hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
111 			hlist_del(&e->link);
112 			kfree(e);
113 		}
114 	}
115 
116 	kfree(rt);
117 }
118 
119 void kvm_free_irq_routing(struct kvm *kvm)
120 {
121 	/* Called only during vm destruction. Nobody can use the pointer
122 	   at this stage */
123 	struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
124 	free_irq_routing_table(rt);
125 }
126 
127 static int setup_routing_entry(struct kvm *kvm,
128 			       struct kvm_irq_routing_table *rt,
129 			       struct kvm_kernel_irq_routing_entry *e,
130 			       const struct kvm_irq_routing_entry *ue)
131 {
132 	struct kvm_kernel_irq_routing_entry *ei;
133 	int r;
134 	u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES);
135 
136 	/*
137 	 * Do not allow GSI to be mapped to the same irqchip more than once.
138 	 * Allow only one to one mapping between GSI and non-irqchip routing.
139 	 */
140 	hlist_for_each_entry(ei, &rt->map[gsi], link)
141 		if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
142 		    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
143 		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
144 			return -EINVAL;
145 
146 	e->gsi = gsi;
147 	e->type = ue->type;
148 	r = kvm_set_routing_entry(kvm, e, ue);
149 	if (r)
150 		return r;
151 	if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
152 		rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
153 
154 	hlist_add_head(&e->link, &rt->map[e->gsi]);
155 
156 	return 0;
157 }
158 
159 void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
160 {
161 }
162 
163 bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
164 {
165 	return true;
166 }
167 
168 int kvm_set_irq_routing(struct kvm *kvm,
169 			const struct kvm_irq_routing_entry *ue,
170 			unsigned nr,
171 			unsigned flags)
172 {
173 	struct kvm_irq_routing_table *new, *old;
174 	struct kvm_kernel_irq_routing_entry *e;
175 	u32 i, j, nr_rt_entries = 0;
176 	int r;
177 
178 	for (i = 0; i < nr; ++i) {
179 		if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
180 			return -EINVAL;
181 		nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
182 	}
183 
184 	nr_rt_entries += 1;
185 
186 	new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT);
187 	if (!new)
188 		return -ENOMEM;
189 
190 	new->nr_rt_entries = nr_rt_entries;
191 	for (i = 0; i < KVM_NR_IRQCHIPS; i++)
192 		for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
193 			new->chip[i][j] = -1;
194 
195 	for (i = 0; i < nr; ++i) {
196 		r = -ENOMEM;
197 		e = kzalloc(sizeof(*e), GFP_KERNEL_ACCOUNT);
198 		if (!e)
199 			goto out;
200 
201 		r = -EINVAL;
202 		switch (ue->type) {
203 		case KVM_IRQ_ROUTING_MSI:
204 			if (ue->flags & ~KVM_MSI_VALID_DEVID)
205 				goto free_entry;
206 			break;
207 		default:
208 			if (ue->flags)
209 				goto free_entry;
210 			break;
211 		}
212 		r = setup_routing_entry(kvm, new, e, ue);
213 		if (r)
214 			goto free_entry;
215 		++ue;
216 	}
217 
218 	mutex_lock(&kvm->irq_lock);
219 	old = rcu_dereference_protected(kvm->irq_routing, 1);
220 	rcu_assign_pointer(kvm->irq_routing, new);
221 	kvm_irq_routing_update(kvm);
222 	kvm_arch_irq_routing_update(kvm);
223 	mutex_unlock(&kvm->irq_lock);
224 
225 	kvm_arch_post_irq_routing_update(kvm);
226 
227 	synchronize_srcu_expedited(&kvm->irq_srcu);
228 
229 	new = old;
230 	r = 0;
231 	goto out;
232 
233 free_entry:
234 	kfree(e);
235 out:
236 	free_irq_routing_table(new);
237 
238 	return r;
239 }
240