kernel/arch/arm/kvm/handle_exit.c

   1 /*
   2  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   3  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  */
  18
  19 #include <linux/kvm.h>
  20 #include <linux/kvm_host.h>
  21 #include <asm/kvm_emulate.h>
  22 #include <asm/kvm_coproc.h>
  23 #include <asm/kvm_mmu.h>
  24 #include <asm/kvm_psci.h>
  25 #include <trace/events/kvm.h>
  26
  27 #include "trace.h"
  28
  29 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  30
  31 static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  32 {
  33         /* SVC called from Hyp mode should never get here */
  34         kvm_debug("SVC called from Hyp mode shouldn't go here\n");
  35         BUG();
  36         return -EINVAL; /* Squash warning */
  37 }
  38
  39 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  40 {
  41         int ret;
  42
  43         trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  44                       kvm_vcpu_hvc_get_imm(vcpu));
  45
  46         ret = kvm_psci_call(vcpu);
  47         if (ret < 0) {
  48                 kvm_inject_undefined(vcpu);
  49                 return 1;
  50         }
  51
  52         return ret;
  53 }
  54
  55 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  56 {
  57         kvm_inject_undefined(vcpu);
  58         return 1;
  59 }
  60
  61 static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  62 {
  63         /* The hypervisor should never cause aborts */
  64         kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  65                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  66         return -EFAULT;
  67 }
  68
  69 static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  70 {
  71         /* This is either an error in the ws. code or an external abort */
  72         kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  73                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  74         return -EFAULT;
  75 }
  76
  77 /**
  78  * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
  79  * @vcpu:       the vcpu pointer
  80  * @run:        the kvm_run structure pointer
  81  *
  82  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  83  * decides to.
  84  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  85  * world-switches and schedule other host processes until there is an
  86  * incoming IRQ or FIQ to the VM.
  87  */
  88 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  89 {
  90         if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
  91                 trace_kvm_wfx(*vcpu_pc(vcpu), true);
  92                 kvm_vcpu_on_spin(vcpu);
  93         } else {
  94                 trace_kvm_wfx(*vcpu_pc(vcpu), false);
  95                 kvm_vcpu_block(vcpu);
  96         }
  97
  98         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  99
 100         return 1;
 101 }
 102
 103 static exit_handle_fn arm_exit_handlers[] = {
 104         [HSR_EC_WFI]            = kvm_handle_wfx,
 105         [HSR_EC_CP15_32]        = kvm_handle_cp15_32,
 106         [HSR_EC_CP15_64]        = kvm_handle_cp15_64,
 107         [HSR_EC_CP14_MR]        = kvm_handle_cp14_access,
 108         [HSR_EC_CP14_LS]        = kvm_handle_cp14_load_store,
 109         [HSR_EC_CP14_64]        = kvm_handle_cp14_access,
 110         [HSR_EC_CP_0_13]        = kvm_handle_cp_0_13_access,
 111         [HSR_EC_CP10_ID]        = kvm_handle_cp10_id,
 112         [HSR_EC_SVC_HYP]        = handle_svc_hyp,
 113         [HSR_EC_HVC]            = handle_hvc,
 114         [HSR_EC_SMC]            = handle_smc,
 115         [HSR_EC_IABT]           = kvm_handle_guest_abort,
 116         [HSR_EC_IABT_HYP]       = handle_pabt_hyp,
 117         [HSR_EC_DABT]           = kvm_handle_guest_abort,
 118         [HSR_EC_DABT_HYP]       = handle_dabt_hyp,
 119 };
 120
 121 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 122 {
 123         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 124
 125         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 126             !arm_exit_handlers[hsr_ec]) {
 127                 kvm_err("Unknown exception class: hsr: %#08x\n",
 128                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
 129                 BUG();
 130         }
 131
 132         return arm_exit_handlers[hsr_ec];
 133 }
 134
 135 /*
 136  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 137  * proper exit to userspace.
 138  */
 139 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 140                        int exception_index)
 141 {
 142         exit_handle_fn exit_handler;
 143
 144         switch (exception_index) {
 145         case ARM_EXCEPTION_IRQ:
 146                 return 1;
 147         case ARM_EXCEPTION_UNDEFINED:
 148                 kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
 149                         kvm_vcpu_get_hyp_pc(vcpu));
 150                 BUG();
 151                 panic("KVM: Hypervisor undefined exception!\n");
 152         case ARM_EXCEPTION_DATA_ABORT:
 153         case ARM_EXCEPTION_PREF_ABORT:
 154         case ARM_EXCEPTION_HVC:
 155                 /*
 156                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 157                  * that fail their condition code check"
 158                  */
 159                 if (!kvm_condition_valid(vcpu)) {
 160                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 161                         return 1;
 162                 }
 163
 164                 exit_handler = kvm_get_exit_handler(vcpu);
 165
 166                 return exit_handler(vcpu, run);
 167         default:
 168                 kvm_pr_unimpl("Unsupported exception type: %d",
 169                               exception_index);
 170                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 171                 return 0;
 172         }
 173 }