linux/virt/kvm/irqchip.c
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   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
  34int 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
  53int 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
  61int 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 */
  83int 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
 112static 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
 132void 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
 140static 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        u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES);
 148
 149        /*
 150         * Do not allow GSI to be mapped to the same irqchip more than once.
 151         * Allow only one to one mapping between GSI and non-irqchip routing.
 152         */
 153        hlist_for_each_entry(ei, &rt->map[gsi], link)
 154                if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
 155                    ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
 156                    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 157                        return -EINVAL;
 158
 159        e->gsi = gsi;
 160        e->type = ue->type;
 161        r = kvm_set_routing_entry(kvm, e, ue);
 162        if (r)
 163                return r;
 164        if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
 165                rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
 166
 167        hlist_add_head(&e->link, &rt->map[e->gsi]);
 168
 169        return 0;
 170}
 171
 172void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
 173{
 174}
 175
 176bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
 177{
 178        return true;
 179}
 180
 181int kvm_set_irq_routing(struct kvm *kvm,
 182                        const struct kvm_irq_routing_entry *ue,
 183                        unsigned nr,
 184                        unsigned flags)
 185{
 186        struct kvm_irq_routing_table *new, *old;
 187        struct kvm_kernel_irq_routing_entry *e;
 188        u32 i, j, nr_rt_entries = 0;
 189        int r;
 190
 191        for (i = 0; i < nr; ++i) {
 192                if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 193                        return -EINVAL;
 194                nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 195        }
 196
 197        nr_rt_entries += 1;
 198
 199        new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT);
 200        if (!new)
 201                return -ENOMEM;
 202
 203        new->nr_rt_entries = nr_rt_entries;
 204        for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 205                for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 206                        new->chip[i][j] = -1;
 207
 208        for (i = 0; i < nr; ++i) {
 209                r = -ENOMEM;
 210                e = kzalloc(sizeof(*e), GFP_KERNEL_ACCOUNT);
 211                if (!e)
 212                        goto out;
 213
 214                r = -EINVAL;
 215                switch (ue->type) {
 216                case KVM_IRQ_ROUTING_MSI:
 217                        if (ue->flags & ~KVM_MSI_VALID_DEVID)
 218                                goto free_entry;
 219                        break;
 220                default:
 221                        if (ue->flags)
 222                                goto free_entry;
 223                        break;
 224                }
 225                r = setup_routing_entry(kvm, new, e, ue);
 226                if (r)
 227                        goto free_entry;
 228                ++ue;
 229        }
 230
 231        mutex_lock(&kvm->irq_lock);
 232        old = rcu_dereference_protected(kvm->irq_routing, 1);
 233        rcu_assign_pointer(kvm->irq_routing, new);
 234        kvm_irq_routing_update(kvm);
 235        kvm_arch_irq_routing_update(kvm);
 236        mutex_unlock(&kvm->irq_lock);
 237
 238        kvm_arch_post_irq_routing_update(kvm);
 239
 240        synchronize_srcu_expedited(&kvm->irq_srcu);
 241
 242        new = old;
 243        r = 0;
 244        goto out;
 245
 246free_entry:
 247        kfree(e);
 248out:
 249        free_irq_routing_table(new);
 250
 251        return r;
 252}
 253