virt/kvm/irqchip.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * irqchip.c: Common API for in kernel interrupt controllers
   4  * Copyright (c) 2007, Intel Corporation.
   5  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
   6  * Copyright (c) 2013, Alexander Graf <agraf@suse.de>
   7  *
   8  * This file is derived from virt/kvm/irq_comm.c.
   9  *
  10  * Authors:
  11  *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  12  *   Alexander Graf <agraf@suse.de>
  13  */
  14
  15 #include <linux/kvm_host.h>
  16 #include <linux/slab.h>
  17 #include <linux/srcu.h>
  18 #include <linux/export.h>
  19 #include <trace/events/kvm.h>
  20
  21 int kvm_irq_map_gsi(struct kvm *kvm,
  22                     struct kvm_kernel_irq_routing_entry *entries, int gsi)
  23 {
  24         struct kvm_irq_routing_table *irq_rt;
  25         struct kvm_kernel_irq_routing_entry *e;
  26         int n = 0;
  27
  28         irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
  29                                         lockdep_is_held(&kvm->irq_lock));
  30         if (irq_rt && gsi < irq_rt->nr_rt_entries) {
  31                 hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
  32                         entries[n] = *e;
  33                         ++n;
  34                 }
  35         }
  36
  37         return n;
  38 }
  39
  40 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
  41 {
  42         struct kvm_irq_routing_table *irq_rt;
  43
  44         irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
  45         return irq_rt->chip[irqchip][pin];
  46 }
  47
  48 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
  49 {
  50         struct kvm_kernel_irq_routing_entry route;
  51
  52         if (!kvm_arch_irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
  53                 return -EINVAL;
  54
  55         route.msi.address_lo = msi->address_lo;
  56         route.msi.address_hi = msi->address_hi;
  57         route.msi.data = msi->data;
  58         route.msi.flags = msi->flags;
  59         route.msi.devid = msi->devid;
  60
  61         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
  62 }
  63
  64 /*
  65  * Return value:
  66  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
  67  *  = 0   Interrupt was coalesced (previous irq is still pending)
  68  *  > 0   Number of CPUs interrupt was delivered to
  69  */
  70 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
  71                 bool line_status)
  72 {
  73         struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
  74         int ret = -1, i, idx;
  75
  76         trace_kvm_set_irq(irq, level, irq_source_id);
  77
  78         /* Not possible to detect if the guest uses the PIC or the
  79          * IOAPIC.  So set the bit in both. The guest will ignore
  80          * writes to the unused one.
  81          */
  82         idx = srcu_read_lock(&kvm->irq_srcu);
  83         i = kvm_irq_map_gsi(kvm, irq_set, irq);
  84         srcu_read_unlock(&kvm->irq_srcu, idx);
  85
  86         while (i--) {
  87                 int r;
  88                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
  89                                    line_status);
  90                 if (r < 0)
  91                         continue;
  92
  93                 ret = r + ((ret < 0) ? 0 : ret);
  94         }
  95
  96         return ret;
  97 }
  98
  99 static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
 100 {
 101         int i;
 102
 103         if (!rt)
 104                 return;
 105
 106         for (i = 0; i < rt->nr_rt_entries; ++i) {
 107                 struct kvm_kernel_irq_routing_entry *e;
 108                 struct hlist_node *n;
 109
 110                 hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
 111                         hlist_del(&e->link);
 112                         kfree(e);
 113                 }
 114         }
 115
 116         kfree(rt);
 117 }
 118
 119 void kvm_free_irq_routing(struct kvm *kvm)
 120 {
 121         /* Called only during vm destruction. Nobody can use the pointer
 122            at this stage */
 123         struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
 124         free_irq_routing_table(rt);
 125 }
 126
 127 static int setup_routing_entry(struct kvm *kvm,
 128                                struct kvm_irq_routing_table *rt,
 129                                struct kvm_kernel_irq_routing_entry *e,
 130                                const struct kvm_irq_routing_entry *ue)
 131 {
 132         struct kvm_kernel_irq_routing_entry *ei;
 133         int r;
 134         u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES);
 135
 136         /*
 137          * Do not allow GSI to be mapped to the same irqchip more than once.
 138          * Allow only one to one mapping between GSI and non-irqchip routing.
 139          */
 140         hlist_for_each_entry(ei, &rt->map[gsi], link)
 141                 if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
 142                     ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
 143                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 144                         return -EINVAL;
 145
 146         e->gsi = gsi;
 147         e->type = ue->type;
 148         r = kvm_set_routing_entry(kvm, e, ue);
 149         if (r)
 150                 return r;
 151         if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
 152                 rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
 153
 154         hlist_add_head(&e->link, &rt->map[e->gsi]);
 155
 156         return 0;
 157 }
 158
 159 void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
 160 {
 161 }
 162
 163 bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
 164 {
 165         return true;
 166 }
 167
 168 int kvm_set_irq_routing(struct kvm *kvm,
 169                         const struct kvm_irq_routing_entry *ue,
 170                         unsigned nr,
 171                         unsigned flags)
 172 {
 173         struct kvm_irq_routing_table *new, *old;
 174         struct kvm_kernel_irq_routing_entry *e;
 175         u32 i, j, nr_rt_entries = 0;
 176         int r;
 177
 178         for (i = 0; i < nr; ++i) {
 179                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 180                         return -EINVAL;
 181                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 182         }
 183
 184         nr_rt_entries += 1;
 185
 186         new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT);
 187         if (!new)
 188                 return -ENOMEM;
 189
 190         new->nr_rt_entries = nr_rt_entries;
 191         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 192                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 193                         new->chip[i][j] = -1;
 194
 195         for (i = 0; i < nr; ++i) {
 196                 r = -ENOMEM;
 197                 e = kzalloc(sizeof(*e), GFP_KERNEL_ACCOUNT);
 198                 if (!e)
 199                         goto out;
 200
 201                 r = -EINVAL;
 202                 switch (ue->type) {
 203                 case KVM_IRQ_ROUTING_MSI:
 204                         if (ue->flags & ~KVM_MSI_VALID_DEVID)
 205                                 goto free_entry;
 206                         break;
 207                 default:
 208                         if (ue->flags)
 209                                 goto free_entry;
 210                         break;
 211                 }
 212                 r = setup_routing_entry(kvm, new, e, ue);
 213                 if (r)
 214                         goto free_entry;
 215                 ++ue;
 216         }
 217
 218         mutex_lock(&kvm->irq_lock);
 219         old = rcu_dereference_protected(kvm->irq_routing, 1);
 220         rcu_assign_pointer(kvm->irq_routing, new);
 221         kvm_irq_routing_update(kvm);
 222         kvm_arch_irq_routing_update(kvm);
 223         mutex_unlock(&kvm->irq_lock);
 224
 225         kvm_arch_post_irq_routing_update(kvm);
 226
 227         synchronize_srcu_expedited(&kvm->irq_srcu);
 228
 229         new = old;
 230         r = 0;
 231         goto out;
 232
 233 free_entry:
 234         kfree(e);
 235 out:
 236         free_irq_routing_table(new);
 237
 238         return r;
 239 }
 240
 241 /*
 242  * Allocate empty IRQ routing by default so that additional setup isn't needed
 243  * when userspace-driven IRQ routing is activated, and so that kvm->irq_routing
 244  * is guaranteed to be non-NULL.
 245  */
 246 int kvm_init_irq_routing(struct kvm *kvm)
 247 {
 248         struct kvm_irq_routing_table *new;
 249         int chip_size;
 250
 251         new = kzalloc(struct_size(new, map, 1), GFP_KERNEL_ACCOUNT);
 252         if (!new)
 253                 return -ENOMEM;
 254
 255         new->nr_rt_entries = 1;
 256
 257         chip_size = sizeof(int) * KVM_NR_IRQCHIPS * KVM_IRQCHIP_NUM_PINS;
 258         memset(new->chip, -1, chip_size);
 259
 260         RCU_INIT_POINTER(kvm->irq_routing, new);
 261
 262         return 0;
 263 }