1/*
  2 * irqchip.c: Common API for in kernel interrupt controllers
  3 * Copyright (c) 2007, Intel Corporation.
  4 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
  5 * Copyright (c) 2013, Alexander Graf <agraf@suse.de>
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms and conditions of the GNU General Public License,
  9 * version 2, as published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope it will be useful, but WITHOUT
 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 14 * more details.
 15 *
 16 * You should have received a copy of the GNU General Public License along with
 17 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 18 * Place - Suite 330, Boston, MA 02111-1307 USA.
 19 *
 20 * This file is derived from virt/kvm/irq_comm.c.
 21 *
 22 * Authors:
 23 *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
 24 *   Alexander Graf <agraf@suse.de>
 25 */
 26
 27#include <linux/kvm_host.h>
 28#include <linux/slab.h>
 29#include <linux/srcu.h>
 30#include <linux/export.h>
 31#include <trace/events/kvm.h>
 32#include "irq.h"
 33
 34int kvm_irq_map_gsi(struct kvm *kvm,
 35		    struct kvm_kernel_irq_routing_entry *entries, int gsi)
 36{
 37	struct kvm_irq_routing_table *irq_rt;
 38	struct kvm_kernel_irq_routing_entry *e;
 39	int n = 0;
 40
 41	irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
 42					lockdep_is_held(&kvm->irq_lock));
 43	if (gsi < irq_rt->nr_rt_entries) {
 44		hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
 45			entries[n] = *e;
 46			++n;
 47		}
 48	}
 49
 50	return n;
 51}
 52
 53int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
 54{
 55	struct kvm_irq_routing_table *irq_rt;
 56
 57	irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
 58	return irq_rt->chip[irqchip][pin];
 59}
 60
 61int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 62{
 63	struct kvm_kernel_irq_routing_entry route;
 64
 65	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
 66		return -EINVAL;
 67
 68	route.msi.address_lo = msi->address_lo;
 69	route.msi.address_hi = msi->address_hi;
 70	route.msi.data = msi->data;
 71
 72	return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
 73}
 74
 75/*
 76 * Return value:
 77 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 78 *  = 0   Interrupt was coalesced (previous irq is still pending)
 79 *  > 0   Number of CPUs interrupt was delivered to
 80 */
 81int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 82		bool line_status)
 83{
 84	struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
 85	int ret = -1, i, idx;
 86
 87	trace_kvm_set_irq(irq, level, irq_source_id);
 88
 89	/* Not possible to detect if the guest uses the PIC or the
 90	 * IOAPIC.  So set the bit in both. The guest will ignore
 91	 * writes to the unused one.
 92	 */
 93	idx = srcu_read_lock(&kvm->irq_srcu);
 94	i = kvm_irq_map_gsi(kvm, irq_set, irq);
 95	srcu_read_unlock(&kvm->irq_srcu, idx);
 96
 97	while (i--) {
 98		int r;
 99		r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
100				   line_status);
101		if (r < 0)
102			continue;
103
104		ret = r + ((ret < 0) ? 0 : ret);
105	}
106
107	return ret;
108}
109
110static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
111{
112	int i;
113
114	if (!rt)
115		return;
116
117	for (i = 0; i < rt->nr_rt_entries; ++i) {
118		struct kvm_kernel_irq_routing_entry *e;
119		struct hlist_node *n;
120
121		hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
122			hlist_del(&e->link);
123			kfree(e);
124		}
125	}
126
127	kfree(rt);
128}
129
130void kvm_free_irq_routing(struct kvm *kvm)
131{
132	/* Called only during vm destruction. Nobody can use the pointer
133	   at this stage */
134	struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
135	free_irq_routing_table(rt);
136}
137
138static int setup_routing_entry(struct kvm_irq_routing_table *rt,
139			       struct kvm_kernel_irq_routing_entry *e,
140			       const struct kvm_irq_routing_entry *ue)
141{
142	int r = -EINVAL;
143	struct kvm_kernel_irq_routing_entry *ei;
144
145	/*
146	 * Do not allow GSI to be mapped to the same irqchip more than once.
147	 * Allow only one to one mapping between GSI and non-irqchip routing.
148	 */
149	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
150		if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
151		    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
152		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
153			return r;
154
155	e->gsi = ue->gsi;
156	e->type = ue->type;
157	r = kvm_set_routing_entry(e, ue);
158	if (r)
159		goto out;
160	if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
161		rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
162
163	hlist_add_head(&e->link, &rt->map[e->gsi]);
164	r = 0;
165out:
166	return r;
167}
168
169void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
170{
171}
172
173int kvm_set_irq_routing(struct kvm *kvm,
174			const struct kvm_irq_routing_entry *ue,
175			unsigned nr,
176			unsigned flags)
177{
178	struct kvm_irq_routing_table *new, *old;
179	u32 i, j, nr_rt_entries = 0;
180	int r;
181
182	for (i = 0; i < nr; ++i) {
183		if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
184			return -EINVAL;
185		nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
186	}
187
188	nr_rt_entries += 1;
189
190	new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
191		      GFP_KERNEL);
192
193	if (!new)
194		return -ENOMEM;
195
196	new->nr_rt_entries = nr_rt_entries;
197	for (i = 0; i < KVM_NR_IRQCHIPS; i++)
198		for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
199			new->chip[i][j] = -1;
200
201	for (i = 0; i < nr; ++i) {
202		struct kvm_kernel_irq_routing_entry *e;
203
204		r = -ENOMEM;
205		e = kzalloc(sizeof(*e), GFP_KERNEL);
206		if (!e)
207			goto out;
208
209		r = -EINVAL;
210		if (ue->flags) {
211			kfree(e);
212			goto out;
213		}
214		r = setup_routing_entry(new, e, ue);
215		if (r) {
216			kfree(e);
217			goto out;
218		}
219		++ue;
220	}
221
222	mutex_lock(&kvm->irq_lock);
223	old = kvm->irq_routing;
224	rcu_assign_pointer(kvm->irq_routing, new);
225	kvm_irq_routing_update(kvm);
226	kvm_arch_irq_routing_update(kvm);
227	mutex_unlock(&kvm->irq_lock);
228
229	kvm_arch_post_irq_routing_update(kvm);
230
231	synchronize_srcu_expedited(&kvm->irq_srcu);
232
233	new = old;
234	r = 0;
235
236out:
237	free_irq_routing_table(new);
238
239	return r;
240}