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 (irq_rt && 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 & ~KVM_MSI_VALID_DEVID))
 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	route.msi.flags = msi->flags;
 72	route.msi.devid = msi->devid;
 73
 74	return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
 75}
 76
 77/*
 78 * Return value:
 79 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 80 *  = 0   Interrupt was coalesced (previous irq is still pending)
 81 *  > 0   Number of CPUs interrupt was delivered to
 82 */
 83int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 84		bool line_status)
 85{
 86	struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
 87	int ret = -1, i, idx;
 88
 89	trace_kvm_set_irq(irq, level, irq_source_id);
 90
 91	/* Not possible to detect if the guest uses the PIC or the
 92	 * IOAPIC.  So set the bit in both. The guest will ignore
 93	 * writes to the unused one.
 94	 */
 95	idx = srcu_read_lock(&kvm->irq_srcu);
 96	i = kvm_irq_map_gsi(kvm, irq_set, irq);
 97	srcu_read_unlock(&kvm->irq_srcu, idx);
 98
 99	while (i--) {
100		int r;
101		r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
102				   line_status);
103		if (r < 0)
104			continue;
105
106		ret = r + ((ret < 0) ? 0 : ret);
107	}
108
109	return ret;
110}
111
112static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
113{
114	int i;
115
116	if (!rt)
117		return;
118
119	for (i = 0; i < rt->nr_rt_entries; ++i) {
120		struct kvm_kernel_irq_routing_entry *e;
121		struct hlist_node *n;
122
123		hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
124			hlist_del(&e->link);
125			kfree(e);
126		}
127	}
128
129	kfree(rt);
130}
131
132void kvm_free_irq_routing(struct kvm *kvm)
133{
134	/* Called only during vm destruction. Nobody can use the pointer
135	   at this stage */
136	struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
137	free_irq_routing_table(rt);
138}
139
140static int setup_routing_entry(struct kvm *kvm,
141			       struct kvm_irq_routing_table *rt,
142			       struct kvm_kernel_irq_routing_entry *e,
143			       const struct kvm_irq_routing_entry *ue)
144{
145	int r = -EINVAL;
146	struct kvm_kernel_irq_routing_entry *ei;
147
148	/*
149	 * Do not allow GSI to be mapped to the same irqchip more than once.
150	 * Allow only one to one mapping between GSI and non-irqchip routing.
151	 */
152	hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
153		if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
154		    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
155		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
156			return r;
157
158	e->gsi = ue->gsi;
159	e->type = ue->type;
160	r = kvm_set_routing_entry(kvm, e, ue);
161	if (r)
162		goto out;
163	if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
164		rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
165
166	hlist_add_head(&e->link, &rt->map[e->gsi]);
167	r = 0;
168out:
169	return r;
170}
171
172void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
173{
174}
175
176int kvm_set_irq_routing(struct kvm *kvm,
177			const struct kvm_irq_routing_entry *ue,
178			unsigned nr,
179			unsigned flags)
180{
181	struct kvm_irq_routing_table *new, *old;
182	struct kvm_kernel_irq_routing_entry *e;
183	u32 i, j, nr_rt_entries = 0;
184	int r;
185
186	for (i = 0; i < nr; ++i) {
187		if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
188			return -EINVAL;
189		nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
190	}
191
192	nr_rt_entries += 1;
193
194	new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
195		      GFP_KERNEL);
196
197	if (!new)
198		return -ENOMEM;
199
200	new->nr_rt_entries = nr_rt_entries;
201	for (i = 0; i < KVM_NR_IRQCHIPS; i++)
202		for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
203			new->chip[i][j] = -1;
204
205	for (i = 0; i < nr; ++i) {
206		r = -ENOMEM;
207		e = kzalloc(sizeof(*e), GFP_KERNEL);
208		if (!e)
209			goto out;
210
211		r = -EINVAL;
212		switch (ue->type) {
213		case KVM_IRQ_ROUTING_MSI:
214			if (ue->flags & ~KVM_MSI_VALID_DEVID)
215				goto free_entry;
216			break;
217		default:
218			if (ue->flags)
219				goto free_entry;
220			break;
221		}
222		r = setup_routing_entry(kvm, new, e, ue);
223		if (r)
224			goto free_entry;
225		++ue;
226	}
227
228	mutex_lock(&kvm->irq_lock);
229	old = kvm->irq_routing;
230	rcu_assign_pointer(kvm->irq_routing, new);
231	kvm_irq_routing_update(kvm);
232	kvm_arch_irq_routing_update(kvm);
233	mutex_unlock(&kvm->irq_lock);
234
235	kvm_arch_post_irq_routing_update(kvm);
236
237	synchronize_srcu_expedited(&kvm->irq_srcu);
238
239	new = old;
240	r = 0;
241	goto out;
242
243free_entry:
244	kfree(e);
245out:
246	free_irq_routing_table(new);
247
248	return r;
249}