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 int 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
  53 int 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
  61 int 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  */
  83 int 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
 112 static 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
 132 void 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
 140 static 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         struct kvm_kernel_irq_routing_entry *ei;
 146         int r;
 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 -EINVAL;
 157
 158         e->gsi = ue->gsi;
 159         e->type = ue->type;
 160         r = kvm_set_routing_entry(kvm, e, ue);
 161         if (r)
 162                 return r;
 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
 168         return 0;
 169 }
 170
 171 void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
 172 {
 173 }
 174
 175 bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
 176 {
 177         return true;
 178 }
 179
 180 int kvm_set_irq_routing(struct kvm *kvm,
 181                         const struct kvm_irq_routing_entry *ue,
 182                         unsigned nr,
 183                         unsigned flags)
 184 {
 185         struct kvm_irq_routing_table *new, *old;
 186         struct kvm_kernel_irq_routing_entry *e;
 187         u32 i, j, nr_rt_entries = 0;
 188         int r;
 189
 190         for (i = 0; i < nr; ++i) {
 191                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 192                         return -EINVAL;
 193                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 194         }
 195
 196         nr_rt_entries += 1;
 197
 198         new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)),
 199                       GFP_KERNEL);
 200
 201         if (!new)
 202                 return -ENOMEM;
 203
 204         new->nr_rt_entries = nr_rt_entries;
 205         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 206                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 207                         new->chip[i][j] = -1;
 208
 209         for (i = 0; i < nr; ++i) {
 210                 r = -ENOMEM;
 211                 e = kzalloc(sizeof(*e), GFP_KERNEL);
 212                 if (!e)
 213                         goto out;
 214
 215                 r = -EINVAL;
 216                 switch (ue->type) {
 217                 case KVM_IRQ_ROUTING_MSI:
 218                         if (ue->flags & ~KVM_MSI_VALID_DEVID)
 219                                 goto free_entry;
 220                         break;
 221                 default:
 222                         if (ue->flags)
 223                                 goto free_entry;
 224                         break;
 225                 }
 226                 r = setup_routing_entry(kvm, new, e, ue);
 227                 if (r)
 228                         goto free_entry;
 229                 ++ue;
 230         }
 231
 232         mutex_lock(&kvm->irq_lock);
 233         old = rcu_dereference_protected(kvm->irq_routing, 1);
 234         rcu_assign_pointer(kvm->irq_routing, new);
 235         kvm_irq_routing_update(kvm);
 236         kvm_arch_irq_routing_update(kvm);
 237         mutex_unlock(&kvm->irq_lock);
 238
 239         kvm_arch_post_irq_routing_update(kvm);
 240
 241         synchronize_srcu_expedited(&kvm->irq_srcu);
 242
 243         new = old;
 244         r = 0;
 245         goto out;
 246
 247 free_entry:
 248         kfree(e);
 249 out:
 250         free_irq_routing_table(new);
 251
 252         return r;
 253 }