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 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
  35 {
  36         struct kvm_irq_ack_notifier *kian;
  37         int gsi, idx;
  38
  39         idx = srcu_read_lock(&kvm->irq_srcu);
  40         gsi = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu)->chip[irqchip][pin];
  41         if (gsi != -1)
  42                 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
  43                                          link)
  44                         if (kian->gsi == gsi) {
  45                                 srcu_read_unlock(&kvm->irq_srcu, idx);
  46                                 return true;
  47                         }
  48
  49         srcu_read_unlock(&kvm->irq_srcu, idx);
  50
  51         return false;
  52 }
  53 EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
  54
  55 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
  56 {
  57         struct kvm_irq_ack_notifier *kian;
  58         int gsi, idx;
  59
  60         trace_kvm_ack_irq(irqchip, pin);
  61
  62         idx = srcu_read_lock(&kvm->irq_srcu);
  63         gsi = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu)->chip[irqchip][pin];
  64         if (gsi != -1)
  65                 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
  66                                          link)
  67                         if (kian->gsi == gsi)
  68                                 kian->irq_acked(kian);
  69         srcu_read_unlock(&kvm->irq_srcu, idx);
  70 }
  71
  72 void kvm_register_irq_ack_notifier(struct kvm *kvm,
  73                                    struct kvm_irq_ack_notifier *kian)
  74 {
  75         mutex_lock(&kvm->irq_lock);
  76         hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
  77         mutex_unlock(&kvm->irq_lock);
  78 #ifdef __KVM_HAVE_IOAPIC
  79         kvm_vcpu_request_scan_ioapic(kvm);
  80 #endif
  81 }
  82
  83 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
  84                                     struct kvm_irq_ack_notifier *kian)
  85 {
  86         mutex_lock(&kvm->irq_lock);
  87         hlist_del_init_rcu(&kian->link);
  88         mutex_unlock(&kvm->irq_lock);
  89         synchronize_srcu(&kvm->irq_srcu);
  90 #ifdef __KVM_HAVE_IOAPIC
  91         kvm_vcpu_request_scan_ioapic(kvm);
  92 #endif
  93 }
  94
  95 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
  96 {
  97         struct kvm_kernel_irq_routing_entry route;
  98
  99         if (!irqchip_in_kernel(kvm) || msi->flags != 0)
 100                 return -EINVAL;
 101
 102         route.msi.address_lo = msi->address_lo;
 103         route.msi.address_hi = msi->address_hi;
 104         route.msi.data = msi->data;
 105
 106         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
 107 }
 108
 109 /*
 110  * Return value:
 111  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 112  *  = 0   Interrupt was coalesced (previous irq is still pending)
 113  *  > 0   Number of CPUs interrupt was delivered to
 114  */
 115 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
 116                 bool line_status)
 117 {
 118         struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
 119         int ret = -1, i = 0, idx;
 120         struct kvm_irq_routing_table *irq_rt;
 121
 122         trace_kvm_set_irq(irq, level, irq_source_id);
 123
 124         /* Not possible to detect if the guest uses the PIC or the
 125          * IOAPIC.  So set the bit in both. The guest will ignore
 126          * writes to the unused one.
 127          */
 128         idx = srcu_read_lock(&kvm->irq_srcu);
 129         irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
 130         if (irq < irq_rt->nr_rt_entries)
 131                 hlist_for_each_entry(e, &irq_rt->map[irq], link)
 132                         irq_set[i++] = *e;
 133         srcu_read_unlock(&kvm->irq_srcu, idx);
 134
 135         while(i--) {
 136                 int r;
 137                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
 138                                    line_status);
 139                 if (r < 0)
 140                         continue;
 141
 142                 ret = r + ((ret < 0) ? 0 : ret);
 143         }
 144
 145         return ret;
 146 }
 147
 148 void kvm_free_irq_routing(struct kvm *kvm)
 149 {
 150         /* Called only during vm destruction. Nobody can use the pointer
 151            at this stage */
 152         kfree(kvm->irq_routing);
 153 }
 154
 155 static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 156                                struct kvm_kernel_irq_routing_entry *e,
 157                                const struct kvm_irq_routing_entry *ue)
 158 {
 159         int r = -EINVAL;
 160         struct kvm_kernel_irq_routing_entry *ei;
 161
 162         /*
 163          * Do not allow GSI to be mapped to the same irqchip more than once.
 164          * Allow only one to one mapping between GSI and MSI.
 165          */
 166         hlist_for_each_entry(ei, &rt->map[ue->gsi], link)
 167                 if (ei->type == KVM_IRQ_ROUTING_MSI ||
 168                     ue->type == KVM_IRQ_ROUTING_MSI ||
 169                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 170                         return r;
 171
 172         e->gsi = ue->gsi;
 173         e->type = ue->type;
 174         r = kvm_set_routing_entry(rt, e, ue);
 175         if (r)
 176                 goto out;
 177
 178         hlist_add_head(&e->link, &rt->map[e->gsi]);
 179         r = 0;
 180 out:
 181         return r;
 182 }
 183
 184 int kvm_set_irq_routing(struct kvm *kvm,
 185                         const struct kvm_irq_routing_entry *ue,
 186                         unsigned nr,
 187                         unsigned flags)
 188 {
 189         struct kvm_irq_routing_table *new, *old;
 190         u32 i, j, nr_rt_entries = 0;
 191         int r;
 192
 193         for (i = 0; i < nr; ++i) {
 194                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 195                         return -EINVAL;
 196                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 197         }
 198
 199         nr_rt_entries += 1;
 200
 201         new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
 202                       + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
 203                       GFP_KERNEL);
 204
 205         if (!new)
 206                 return -ENOMEM;
 207
 208         new->rt_entries = (void *)&new->map[nr_rt_entries];
 209
 210         new->nr_rt_entries = nr_rt_entries;
 211         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 212                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 213                         new->chip[i][j] = -1;
 214
 215         for (i = 0; i < nr; ++i) {
 216                 r = -EINVAL;
 217                 if (ue->flags)
 218                         goto out;
 219                 r = setup_routing_entry(new, &new->rt_entries[i], ue);
 220                 if (r)
 221                         goto out;
 222                 ++ue;
 223         }
 224
 225         mutex_lock(&kvm->irq_lock);
 226         old = kvm->irq_routing;
 227         kvm_irq_routing_update(kvm, new);
 228         mutex_unlock(&kvm->irq_lock);
 229
 230         synchronize_srcu_expedited(&kvm->irq_srcu);
 231
 232         new = old;
 233         r = 0;
 234
 235 out:
 236         kfree(new);
 237         return r;
 238 }