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
 21int 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
 40int 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
 48int 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 */
 70int 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
 99static 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
119void 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
127static 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
159void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
160{
161}
162
163bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
164{
165	return true;
166}
167
168int 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
233free_entry:
234	kfree(e);
235out:
236	free_irq_routing_table(new);
237
238	return r;
239}