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