virt/kvm/irqchip.c

   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/export.h>
  30 #include <trace/events/kvm.h>
  31 #include "irq.h"
  32
  33 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
  34 {
  35         struct kvm_irq_ack_notifier *kian;
  36         int gsi;
  37
  38         rcu_read_lock();
  39         gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
  40         if (gsi != -1)
  41                 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
  42                                          link)
  43                         if (kian->gsi == gsi) {
  44                                 rcu_read_unlock();
  45                                 return true;
  46                         }
  47
  48         rcu_read_unlock();
  49
  50         return false;
  51 }
  52 EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
  53
  54 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
  55 {
  56         struct kvm_irq_ack_notifier *kian;
  57         int gsi;
  58
  59         trace_kvm_ack_irq(irqchip, pin);
  60
  61         rcu_read_lock();
  62         gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
  63         if (gsi != -1)
  64                 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
  65                                          link)
  66                         if (kian->gsi == gsi)
  67                                 kian->irq_acked(kian);
  68         rcu_read_unlock();
  69 }
  70
  71 void kvm_register_irq_ack_notifier(struct kvm *kvm,
  72                                    struct kvm_irq_ack_notifier *kian)
  73 {
  74         mutex_lock(&kvm->irq_lock);
  75         hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
  76         mutex_unlock(&kvm->irq_lock);
  77 #ifdef __KVM_HAVE_IOAPIC
  78         kvm_vcpu_request_scan_ioapic(kvm);
  79 #endif
  80 }
  81
  82 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
  83                                     struct kvm_irq_ack_notifier *kian)
  84 {
  85         mutex_lock(&kvm->irq_lock);
  86         hlist_del_init_rcu(&kian->link);
  87         mutex_unlock(&kvm->irq_lock);
  88         synchronize_rcu();
  89 #ifdef __KVM_HAVE_IOAPIC
  90         kvm_vcpu_request_scan_ioapic(kvm);
  91 #endif
  92 }
  93
  94 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
  95 {
  96         struct kvm_kernel_irq_routing_entry route;
  97
  98         if (!irqchip_in_kernel(kvm) || msi->flags != 0)
  99                 return -EINVAL;
 100
 101         route.msi.address_lo = msi->address_lo;
 102         route.msi.address_hi = msi->address_hi;
 103         route.msi.data = msi->data;
 104
 105         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
 106 }
 107
 108 /*
 109  * Return value:
 110  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 111  *  = 0   Interrupt was coalesced (previous irq is still pending)
 112  *  > 0   Number of CPUs interrupt was delivered to
 113  */
 114 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 115                 bool line_status)
 116 {
 117         struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
 118         int ret = -1, i = 0;
 119         struct kvm_irq_routing_table *irq_rt;
 120
 121         trace_kvm_set_irq(irq, level, irq_source_id);
 122
 123         /* Not possible to detect if the guest uses the PIC or the
 124          * IOAPIC.  So set the bit in both. The guest will ignore
 125          * writes to the unused one.
 126          */
 127         rcu_read_lock();
 128         irq_rt = rcu_dereference(kvm->irq_routing);
 129         if (irq < irq_rt->nr_rt_entries)
 130                 hlist_for_each_entry(e, &irq_rt->map[irq], link)
 131                         irq_set[i++] = *e;
 132         rcu_read_unlock();
 133
 134         while(i--) {
 135                 int r;
 136                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
 137                                    line_status);
 138                 if (r < 0)
 139                         continue;
 140
 141                 ret = r + ((ret < 0) ? 0 : ret);
 142         }
 143
 144         return ret;
 145 }
 146
 147 void kvm_free_irq_routing(struct kvm *kvm)
 148 {
 149         /* Called only during vm destruction. Nobody can use the pointer
 150            at this stage */
 151         kfree(kvm->irq_routing);
 152 }
 153
 154 static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 155                                struct kvm_kernel_irq_routing_entry *e,
 156                                const struct kvm_irq_routing_entry *ue)
 157 {
 158         int r = -EINVAL;
 159         struct kvm_kernel_irq_routing_entry *ei;
 160
 161         /*
 162          * Do not allow GSI to be mapped to the same irqchip more than once.
 163          * Allow only one to one mapping between GSI and MSI.
 164          */
 165         hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
 166                 if (ei->type == KVM_IRQ_ROUTING_MSI ||
 167                     ue->type == KVM_IRQ_ROUTING_MSI ||
 168                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 169                         return r;
 170
 171         e->gsi = ue->gsi;
 172         e->type = ue->type;
 173         r = kvm_set_routing_entry(rt, e, ue);
 174         if (r)
 175                 goto out;
 176
 177         hlist_add_head(&e->link, &rt->map[e->gsi]);
 178         r = 0;
 179 out:
 180         return r;
 181 }
 182
 183 int kvm_set_irq_routing(struct kvm *kvm,
 184                         const struct kvm_irq_routing_entry *ue,
 185                         unsigned nr,
 186                         unsigned flags)
 187 {
 188         struct kvm_irq_routing_table *new, *old;
 189         u32 i, j, nr_rt_entries = 0;
 190         int r;
 191
 192         for (i = 0; i < nr; ++i) {
 193                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 194                         return -EINVAL;
 195                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 196         }
 197
 198         nr_rt_entries += 1;
 199
 200         new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
 201                       + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
 202                       GFP_KERNEL);
 203
 204         if (!new)
 205                 return -ENOMEM;
 206
 207         new->rt_entries = (void *)&new->map[nr_rt_entries];
 208
 209         new->nr_rt_entries = nr_rt_entries;
 210         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 211                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 212                         new->chip[i][j] = -1;
 213
 214         for (i = 0; i < nr; ++i) {
 215                 r = -EINVAL;
 216                 if (ue->flags)
 217                         goto out;
 218                 r = setup_routing_entry(new, &new->rt_entries[i], ue);
 219                 if (r)
 220                         goto out;
 221                 ++ue;
 222         }
 223
 224         mutex_lock(&kvm->irq_lock);
 225         old = kvm->irq_routing;
 226         kvm_irq_routing_update(kvm, new);
 227         mutex_unlock(&kvm->irq_lock);
 228
 229         synchronize_rcu();
 230
 231         new = old;
 232         r = 0;
 233
 234 out:
 235         kfree(new);
 236         return r;
 237 }