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 #include "trace.h"
  30
  31 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  32
  33 static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  34 {
  35         /* SVC called from Hyp mode should never get here */
  36         kvm_debug("SVC called from Hyp mode shouldn't go here\n");
  37         BUG();
  38         return -EINVAL; /* Squash warning */
  39 }
  40
  41 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  42 {
  43         trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  44                       kvm_vcpu_hvc_get_imm(vcpu));
  45
  46         if (kvm_psci_call(vcpu))
  47                 return 1;
  48
  49         kvm_inject_undefined(vcpu);
  50         return 1;
  51 }
  52
  53 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  54 {
  55         if (kvm_psci_call(vcpu))
  56                 return 1;
  57
  58         kvm_inject_undefined(vcpu);
  59         return 1;
  60 }
  61
  62 static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  63 {
  64         /* The hypervisor should never cause aborts */
  65         kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  66                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  67         return -EFAULT;
  68 }
  69
  70 static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  71 {
  72         /* This is either an error in the ws. code or an external abort */
  73         kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  74                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  75         return -EFAULT;
  76 }
  77
  78 /**
  79  * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest
  80  * @vcpu:       the vcpu pointer
  81  * @run:        the kvm_run structure pointer
  82  *
  83  * Simply sets the wait_for_interrupts flag on the vcpu structure, which will
  84  * halt execution of world-switches and schedule other host processes until
  85  * there is an incoming IRQ or FIQ to the VM.
  86  */
  87 static int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)
  88 {
  89         trace_kvm_wfi(*vcpu_pc(vcpu));
  90         kvm_vcpu_block(vcpu);
  91         return 1;
  92 }
  93
  94 static exit_handle_fn arm_exit_handlers[] = {
  95         [HSR_EC_WFI]            = kvm_handle_wfi,
  96         [HSR_EC_CP15_32]        = kvm_handle_cp15_32,
  97         [HSR_EC_CP15_64]        = kvm_handle_cp15_64,
  98         [HSR_EC_CP14_MR]        = kvm_handle_cp14_access,
  99         [HSR_EC_CP14_LS]        = kvm_handle_cp14_load_store,
 100         [HSR_EC_CP14_64]        = kvm_handle_cp14_access,
 101         [HSR_EC_CP_0_13]        = kvm_handle_cp_0_13_access,
 102         [HSR_EC_CP10_ID]        = kvm_handle_cp10_id,
 103         [HSR_EC_SVC_HYP]        = handle_svc_hyp,
 104         [HSR_EC_HVC]            = handle_hvc,
 105         [HSR_EC_SMC]            = handle_smc,
 106         [HSR_EC_IABT]           = kvm_handle_guest_abort,
 107         [HSR_EC_IABT_HYP]       = handle_pabt_hyp,
 108         [HSR_EC_DABT]           = kvm_handle_guest_abort,
 109         [HSR_EC_DABT_HYP]       = handle_dabt_hyp,
 110 };
 111
 112 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 113 {
 114         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 115
 116         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 117             !arm_exit_handlers[hsr_ec]) {
 118                 kvm_err("Unknown exception class: hsr: %#08x\n",
 119                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
 120                 BUG();
 121         }
 122
 123         return arm_exit_handlers[hsr_ec];
 124 }
 125
 126 /*
 127  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 128  * proper exit to userspace.
 129  */
 130 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 131                        int exception_index)
 132 {
 133         exit_handle_fn exit_handler;
 134
 135         switch (exception_index) {
 136         case ARM_EXCEPTION_IRQ:
 137                 return 1;
 138         case ARM_EXCEPTION_UNDEFINED:
 139                 kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
 140                         kvm_vcpu_get_hyp_pc(vcpu));
 141                 BUG();
 142                 panic("KVM: Hypervisor undefined exception!\n");
 143         case ARM_EXCEPTION_DATA_ABORT:
 144         case ARM_EXCEPTION_PREF_ABORT:
 145         case ARM_EXCEPTION_HVC:
 146                 /*
 147                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 148                  * that fail their condition code check"
 149                  */
 150                 if (!kvm_condition_valid(vcpu)) {
 151                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 152                         return 1;
 153                 }
 154
 155                 exit_handler = kvm_get_exit_handler(vcpu);
 156
 157                 return exit_handler(vcpu, run);
 158         default:
 159                 kvm_pr_unimpl("Unsupported exception type: %d",
 160                               exception_index);
 161                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 162                 return 0;
 163         }
 164 }