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_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  32 {
  33         int ret;
  34
  35         trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  36                       kvm_vcpu_hvc_get_imm(vcpu));
  37         vcpu->stat.hvc_exit_stat++;
  38
  39         ret = kvm_psci_call(vcpu);
  40         if (ret < 0) {
  41                 kvm_inject_undefined(vcpu);
  42                 return 1;
  43         }
  44
  45         return ret;
  46 }
  47
  48 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  49 {
  50         kvm_inject_undefined(vcpu);
  51         return 1;
  52 }
  53
  54 /**
  55  * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
  56  * @vcpu:       the vcpu pointer
  57  * @run:        the kvm_run structure pointer
  58  *
  59  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  60  * decides to.
  61  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  62  * world-switches and schedule other host processes until there is an
  63  * incoming IRQ or FIQ to the VM.
  64  */
  65 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  66 {
  67         if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE) {
  68                 trace_kvm_wfx(*vcpu_pc(vcpu), true);
  69                 vcpu->stat.wfe_exit_stat++;
  70                 kvm_vcpu_on_spin(vcpu);
  71         } else {
  72                 trace_kvm_wfx(*vcpu_pc(vcpu), false);
  73                 vcpu->stat.wfi_exit_stat++;
  74                 kvm_vcpu_block(vcpu);
  75         }
  76
  77         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  78
  79         return 1;
  80 }
  81
  82 static exit_handle_fn arm_exit_handlers[] = {
  83         [HSR_EC_WFI]            = kvm_handle_wfx,
  84         [HSR_EC_CP15_32]        = kvm_handle_cp15_32,
  85         [HSR_EC_CP15_64]        = kvm_handle_cp15_64,
  86         [HSR_EC_CP14_MR]        = kvm_handle_cp14_access,
  87         [HSR_EC_CP14_LS]        = kvm_handle_cp14_load_store,
  88         [HSR_EC_CP14_64]        = kvm_handle_cp14_access,
  89         [HSR_EC_CP_0_13]        = kvm_handle_cp_0_13_access,
  90         [HSR_EC_CP10_ID]        = kvm_handle_cp10_id,
  91         [HSR_EC_HVC]            = handle_hvc,
  92         [HSR_EC_SMC]            = handle_smc,
  93         [HSR_EC_IABT]           = kvm_handle_guest_abort,
  94         [HSR_EC_DABT]           = kvm_handle_guest_abort,
  95 };
  96
  97 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
  98 {
  99         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 100
 101         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 102             !arm_exit_handlers[hsr_ec]) {
 103                 kvm_err("Unknown exception class: hsr: %#08x\n",
 104                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
 105                 BUG();
 106         }
 107
 108         return arm_exit_handlers[hsr_ec];
 109 }
 110
 111 /*
 112  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 113  * proper exit to userspace.
 114  */
 115 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 116                        int exception_index)
 117 {
 118         exit_handle_fn exit_handler;
 119
 120         if (ARM_ABORT_PENDING(exception_index)) {
 121                 u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 122
 123                 /*
 124                  * HVC/SMC already have an adjusted PC, which we need
 125                  * to correct in order to return to after having
 126                  * injected the abort.
 127                  */
 128                 if (hsr_ec == HSR_EC_HVC || hsr_ec == HSR_EC_SMC) {
 129                         u32 adj =  kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2;
 130                         *vcpu_pc(vcpu) -= adj;
 131                 }
 132
 133                 kvm_inject_vabt(vcpu);
 134                 return 1;
 135         }
 136
 137         exception_index = ARM_EXCEPTION_CODE(exception_index);
 138
 139         switch (exception_index) {
 140         case ARM_EXCEPTION_IRQ:
 141                 return 1;
 142         case ARM_EXCEPTION_HVC:
 143                 /*
 144                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 145                  * that fail their condition code check"
 146                  */
 147                 if (!kvm_condition_valid(vcpu)) {
 148                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 149                         return 1;
 150                 }
 151
 152                 exit_handler = kvm_get_exit_handler(vcpu);
 153
 154                 return exit_handler(vcpu, run);
 155         case ARM_EXCEPTION_DATA_ABORT:
 156                 kvm_inject_vabt(vcpu);
 157                 return 1;
 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 }