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