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/srcu.h>
  30 #include <linux/export.h>
  31 #include <trace/events/kvm.h>
  32 #include "irq.h"
  33
  34 struct kvm_irq_routing_table {
  35         int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
  36         u32 nr_rt_entries;
  37         /*
  38          * Array indexed by gsi. Each entry contains list of irq chips
  39          * the gsi is connected to.
  40          */
  41         struct hlist_head map[0];
  42 };
  43
  44 int kvm_irq_map_gsi(struct kvm *kvm,
  45                     struct kvm_kernel_irq_routing_entry *entries, int gsi)
  46 {
  47         struct kvm_irq_routing_table *irq_rt;
  48         struct kvm_kernel_irq_routing_entry *e;
  49         int n = 0;
  50
  51         irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
  52                                         lockdep_is_held(&kvm->irq_lock));
  53         if (gsi < irq_rt->nr_rt_entries) {
  54                 hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
  55                         entries[n] = *e;
  56                         ++n;
  57                 }
  58         }
  59
  60         return n;
  61 }
  62
  63 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
  64 {
  65         struct kvm_irq_routing_table *irq_rt;
  66
  67         irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
  68         return irq_rt->chip[irqchip][pin];
  69 }
  70
  71 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
  72 {
  73         struct kvm_kernel_irq_routing_entry route;
  74
  75         if (!irqchip_in_kernel(kvm) || msi->flags != 0)
  76                 return -EINVAL;
  77
  78         route.msi.address_lo = msi->address_lo;
  79         route.msi.address_hi = msi->address_hi;
  80         route.msi.data = msi->data;
  81
  82         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
  83 }
  84
  85 /*
  86  * Return value:
  87  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
  88  *  = 0   Interrupt was coalesced (previous irq is still pending)
  89  *  > 0   Number of CPUs interrupt was delivered to
  90  */
  91 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
  92                 bool line_status)
  93 {
  94         struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
  95         int ret = -1, i, idx;
  96
  97         trace_kvm_set_irq(irq, level, irq_source_id);
  98
  99         /* Not possible to detect if the guest uses the PIC or the
 100          * IOAPIC.  So set the bit in both. The guest will ignore
 101          * writes to the unused one.
 102          */
 103         idx = srcu_read_lock(&kvm->irq_srcu);
 104         i = kvm_irq_map_gsi(kvm, irq_set, irq);
 105         srcu_read_unlock(&kvm->irq_srcu, idx);
 106
 107         while (i--) {
 108                 int r;
 109                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
 110                                    line_status);
 111                 if (r < 0)
 112                         continue;
 113
 114                 ret = r + ((ret < 0) ? 0 : ret);
 115         }
 116
 117         return ret;
 118 }
 119
 120 static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
 121 {
 122         int i;
 123
 124         if (!rt)
 125                 return;
 126
 127         for (i = 0; i < rt->nr_rt_entries; ++i) {
 128                 struct kvm_kernel_irq_routing_entry *e;
 129                 struct hlist_node *n;
 130
 131                 hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
 132                         hlist_del(&e->link);
 133                         kfree(e);
 134                 }
 135         }
 136
 137         kfree(rt);
 138 }
 139
 140 void kvm_free_irq_routing(struct kvm *kvm)
 141 {
 142         /* Called only during vm destruction. Nobody can use the pointer
 143            at this stage */
 144         struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
 145         free_irq_routing_table(rt);
 146 }
 147
 148 static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 149                                struct kvm_kernel_irq_routing_entry *e,
 150                                const struct kvm_irq_routing_entry *ue)
 151 {
 152         int r = -EINVAL;
 153         struct kvm_kernel_irq_routing_entry *ei;
 154
 155         /*
 156          * Do not allow GSI to be mapped to the same irqchip more than once.
 157          * Allow only one to one mapping between GSI and MSI.
 158          */
 159         hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
 160                 if (ei->type == KVM_IRQ_ROUTING_MSI ||
 161                     ue->type == KVM_IRQ_ROUTING_MSI ||
 162                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 163                         return r;
 164
 165         e->gsi = ue->gsi;
 166         e->type = ue->type;
 167         r = kvm_set_routing_entry(e, ue);
 168         if (r)
 169                 goto out;
 170         if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
 171                 rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
 172
 173         hlist_add_head(&e->link, &rt->map[e->gsi]);
 174         r = 0;
 175 out:
 176         return r;
 177 }
 178
 179 int kvm_set_irq_routing(struct kvm *kvm,
 180                         const struct kvm_irq_routing_entry *ue,
 181                         unsigned nr,
 182                         unsigned flags)
 183 {
 184         struct kvm_irq_routing_table *new, *old;
 185         u32 i, j, nr_rt_entries = 0;
 186         int r;
 187
 188         for (i = 0; i < nr; ++i) {
 189                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 190                         return -EINVAL;
 191                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 192         }
 193
 194         nr_rt_entries += 1;
 195
 196         new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
 197                       GFP_KERNEL);
 198
 199         if (!new)
 200                 return -ENOMEM;
 201
 202         new->nr_rt_entries = nr_rt_entries;
 203         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 204                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 205                         new->chip[i][j] = -1;
 206
 207         for (i = 0; i < nr; ++i) {
 208                 struct kvm_kernel_irq_routing_entry *e;
 209
 210                 r = -ENOMEM;
 211                 e = kzalloc(sizeof(*e), GFP_KERNEL);
 212                 if (!e)
 213                         goto out;
 214
 215                 r = -EINVAL;
 216                 if (ue->flags) {
 217                         kfree(e);
 218                         goto out;
 219                 }
 220                 r = setup_routing_entry(new, e, ue);
 221                 if (r) {
 222                         kfree(e);
 223                         goto out;
 224                 }
 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         mutex_unlock(&kvm->irq_lock);
 233
 234         synchronize_srcu_expedited(&kvm->irq_srcu);
 235
 236         new = old;
 237         r = 0;
 238
 239 out:
 240         free_irq_routing_table(new);
 241
 242         return r;
 243 }