virt/kvm/arm/vgic/vgic-init.c

   1 /*
   2  * Copyright (C) 2015, 2016 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/uaccess.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/cpu.h>
  20 #include <linux/kvm_host.h>
  21 #include <kvm/arm_vgic.h>
  22 #include <asm/kvm_mmu.h>
  23 #include "vgic.h"
  24
  25 /* GENERIC PROBE */
  26
  27 static void vgic_init_maintenance_interrupt(void *info)
  28 {
  29         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
  30 }
  31
  32 static int vgic_cpu_notify(struct notifier_block *self,
  33                            unsigned long action, void *cpu)
  34 {
  35         switch (action) {
  36         case CPU_STARTING:
  37         case CPU_STARTING_FROZEN:
  38                 vgic_init_maintenance_interrupt(NULL);
  39                 break;
  40         case CPU_DYING:
  41         case CPU_DYING_FROZEN:
  42                 disable_percpu_irq(kvm_vgic_global_state.maint_irq);
  43                 break;
  44         }
  45
  46         return NOTIFY_OK;
  47 }
  48
  49 static struct notifier_block vgic_cpu_nb = {
  50         .notifier_call = vgic_cpu_notify,
  51 };
  52
  53 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
  54 {
  55         /*
  56          * We cannot rely on the vgic maintenance interrupt to be
  57          * delivered synchronously. This means we can only use it to
  58          * exit the VM, and we perform the handling of EOIed
  59          * interrupts on the exit path (see vgic_process_maintenance).
  60          */
  61         return IRQ_HANDLED;
  62 }
  63
  64 /**
  65  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
  66  * according to the host GIC model. Accordingly calls either
  67  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
  68  * instantiated by a guest later on .
  69  */
  70 int kvm_vgic_hyp_init(void)
  71 {
  72         const struct gic_kvm_info *gic_kvm_info;
  73         int ret;
  74
  75         gic_kvm_info = gic_get_kvm_info();
  76         if (!gic_kvm_info)
  77                 return -ENODEV;
  78
  79         if (!gic_kvm_info->maint_irq) {
  80                 kvm_err("No vgic maintenance irq\n");
  81                 return -ENXIO;
  82         }
  83
  84         switch (gic_kvm_info->type) {
  85         case GIC_V2:
  86                 ret = vgic_v2_probe(gic_kvm_info);
  87                 break;
  88         case GIC_V3:
  89                 ret = vgic_v3_probe(gic_kvm_info);
  90                 break;
  91         default:
  92                 ret = -ENODEV;
  93         };
  94
  95         if (ret)
  96                 return ret;
  97
  98         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
  99         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 100                                  vgic_maintenance_handler,
 101                                  "vgic", kvm_get_running_vcpus());
 102         if (ret) {
 103                 kvm_err("Cannot register interrupt %d\n",
 104                         kvm_vgic_global_state.maint_irq);
 105                 return ret;
 106         }
 107
 108         ret = __register_cpu_notifier(&vgic_cpu_nb);
 109         if (ret) {
 110                 kvm_err("Cannot register vgic CPU notifier\n");
 111                 goto out_free_irq;
 112         }
 113
 114         on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
 115
 116         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 117         return 0;
 118
 119 out_free_irq:
 120         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 121                         kvm_get_running_vcpus());
 122         return ret;
 123 }