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 #include "irq.h"
  21
  22 int kvm_irq_map_gsi(struct kvm *kvm,
  23                     struct kvm_kernel_irq_routing_entry *entries, int gsi)
  24 {
  25         struct kvm_irq_routing_table *irq_rt;
  26         struct kvm_kernel_irq_routing_entry *e;
  27         int n = 0;
  28
  29         irq_rt = srcu_dereference_check(kvm->irq_routing, &kvm->irq_srcu,
  30                                         lockdep_is_held(&kvm->irq_lock));
  31         if (irq_rt && gsi < irq_rt->nr_rt_entries) {
  32                 hlist_for_each_entry(e, &irq_rt->map[gsi], link) {
  33                         entries[n] = *e;
  34                         ++n;
  35                 }
  36         }
  37
  38         return n;
  39 }
  40
  41 int kvm_irq_map_chip_pin(struct kvm *kvm, unsigned irqchip, unsigned pin)
  42 {
  43         struct kvm_irq_routing_table *irq_rt;
  44
  45         irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
  46         return irq_rt->chip[irqchip][pin];
  47 }
  48
  49 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
  50 {
  51         struct kvm_kernel_irq_routing_entry route;
  52
  53         if (!irqchip_in_kernel(kvm) || (msi->flags & ~KVM_MSI_VALID_DEVID))
  54                 return -EINVAL;
  55
  56         route.msi.address_lo = msi->address_lo;
  57         route.msi.address_hi = msi->address_hi;
  58         route.msi.data = msi->data;
  59         route.msi.flags = msi->flags;
  60         route.msi.devid = msi->devid;
  61
  62         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, false);
  63 }
  64
  65 /*
  66  * Return value:
  67  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
  68  *  = 0   Interrupt was coalesced (previous irq is still pending)
  69  *  > 0   Number of CPUs interrupt was delivered to
  70  */
  71 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
  72                 bool line_status)
  73 {
  74         struct kvm_kernel_irq_routing_entry irq_set[KVM_NR_IRQCHIPS];
  75         int ret = -1, i, idx;
  76
  77         trace_kvm_set_irq(irq, level, irq_source_id);
  78
  79         /* Not possible to detect if the guest uses the PIC or the
  80          * IOAPIC.  So set the bit in both. The guest will ignore
  81          * writes to the unused one.
  82          */
  83         idx = srcu_read_lock(&kvm->irq_srcu);
  84         i = kvm_irq_map_gsi(kvm, irq_set, irq);
  85         srcu_read_unlock(&kvm->irq_srcu, idx);
  86
  87         while (i--) {
  88                 int r;
  89                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level,
  90                                    line_status);
  91                 if (r < 0)
  92                         continue;
  93
  94                 ret = r + ((ret < 0) ? 0 : ret);
  95         }
  96
  97         return ret;
  98 }
  99
 100 static void free_irq_routing_table(struct kvm_irq_routing_table *rt)
 101 {
 102         int i;
 103
 104         if (!rt)
 105                 return;
 106
 107         for (i = 0; i < rt->nr_rt_entries; ++i) {
 108                 struct kvm_kernel_irq_routing_entry *e;
 109                 struct hlist_node *n;
 110
 111                 hlist_for_each_entry_safe(e, n, &rt->map[i], link) {
 112                         hlist_del(&e->link);
 113                         kfree(e);
 114                 }
 115         }
 116
 117         kfree(rt);
 118 }
 119
 120 void kvm_free_irq_routing(struct kvm *kvm)
 121 {
 122         /* Called only during vm destruction. Nobody can use the pointer
 123            at this stage */
 124         struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing);
 125         free_irq_routing_table(rt);
 126 }
 127
 128 static int setup_routing_entry(struct kvm *kvm,
 129                                struct kvm_irq_routing_table *rt,
 130                                struct kvm_kernel_irq_routing_entry *e,
 131                                const struct kvm_irq_routing_entry *ue)
 132 {
 133         struct kvm_kernel_irq_routing_entry *ei;
 134         int r;
 135         u32 gsi = array_index_nospec(ue->gsi, KVM_MAX_IRQ_ROUTES);
 136
 137         /*
 138          * Do not allow GSI to be mapped to the same irqchip more than once.
 139          * Allow only one to one mapping between GSI and non-irqchip routing.
 140          */
 141         hlist_for_each_entry(ei, &rt->map[gsi], link)
 142                 if (ei->type != KVM_IRQ_ROUTING_IRQCHIP ||
 143                     ue->type != KVM_IRQ_ROUTING_IRQCHIP ||
 144                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 145                         return -EINVAL;
 146
 147         e->gsi = gsi;
 148         e->type = ue->type;
 149         r = kvm_set_routing_entry(kvm, e, ue);
 150         if (r)
 151                 return r;
 152         if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
 153                 rt->chip[e->irqchip.irqchip][e->irqchip.pin] = e->gsi;
 154
 155         hlist_add_head(&e->link, &rt->map[e->gsi]);
 156
 157         return 0;
 158 }
 159
 160 void __attribute__((weak)) kvm_arch_irq_routing_update(struct kvm *kvm)
 161 {
 162 }
 163
 164 bool __weak kvm_arch_can_set_irq_routing(struct kvm *kvm)
 165 {
 166         return true;
 167 }
 168
 169 int kvm_set_irq_routing(struct kvm *kvm,
 170                         const struct kvm_irq_routing_entry *ue,
 171                         unsigned nr,
 172                         unsigned flags)
 173 {
 174         struct kvm_irq_routing_table *new, *old;
 175         struct kvm_kernel_irq_routing_entry *e;
 176         u32 i, j, nr_rt_entries = 0;
 177         int r;
 178
 179         for (i = 0; i < nr; ++i) {
 180                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 181                         return -EINVAL;
 182                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 183         }
 184
 185         nr_rt_entries += 1;
 186
 187         new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT);
 188         if (!new)
 189                 return -ENOMEM;
 190
 191         new->nr_rt_entries = nr_rt_entries;
 192         for (i = 0; i < KVM_NR_IRQCHIPS; i++)
 193                 for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++)
 194                         new->chip[i][j] = -1;
 195
 196         for (i = 0; i < nr; ++i) {
 197                 r = -ENOMEM;
 198                 e = kzalloc(sizeof(*e), GFP_KERNEL_ACCOUNT);
 199                 if (!e)
 200                         goto out;
 201
 202                 r = -EINVAL;
 203                 switch (ue->type) {
 204                 case KVM_IRQ_ROUTING_MSI:
 205                         if (ue->flags & ~KVM_MSI_VALID_DEVID)
 206                                 goto free_entry;
 207                         break;
 208                 default:
 209                         if (ue->flags)
 210                                 goto free_entry;
 211                         break;
 212                 }
 213                 r = setup_routing_entry(kvm, new, e, ue);
 214                 if (r)
 215                         goto free_entry;
 216                 ++ue;
 217         }
 218
 219         mutex_lock(&kvm->irq_lock);
 220         old = rcu_dereference_protected(kvm->irq_routing, 1);
 221         rcu_assign_pointer(kvm->irq_routing, new);
 222         kvm_irq_routing_update(kvm);
 223         kvm_arch_irq_routing_update(kvm);
 224         mutex_unlock(&kvm->irq_lock);
 225
 226         kvm_arch_post_irq_routing_update(kvm);
 227
 228         synchronize_srcu_expedited(&kvm->irq_srcu);
 229
 230         new = old;
 231         r = 0;
 232         goto out;
 233
 234 free_entry:
 235         kfree(e);
 236 out:
 237         free_irq_routing_table(new);
 238
 239         return r;
 240 }