arch/arm64/kvm/handle_exit.c

   1 /*
   2  * Copyright (C) 2012,2013 - ARM Ltd
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * Derived from arch/arm/kvm/handle_exit.c:
   6  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   7  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <linux/kvm.h>
  23 #include <linux/kvm_host.h>
  24
  25 #include <asm/esr.h>
  26 #include <asm/kvm_coproc.h>
  27 #include <asm/kvm_emulate.h>
  28 #include <asm/kvm_mmu.h>
  29 #include <asm/kvm_psci.h>
  30
  31 #define CREATE_TRACE_POINTS
  32 #include "trace.h"
  33
  34 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  35
  36 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  37 {
  38         int ret;
  39
  40         trace_kvm_hvc_arm64(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  41                             kvm_vcpu_hvc_get_imm(vcpu));
  42
  43         ret = kvm_psci_call(vcpu);
  44         if (ret < 0) {
  45                 kvm_inject_undefined(vcpu);
  46                 return 1;
  47         }
  48
  49         return ret;
  50 }
  51
  52 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  53 {
  54         kvm_inject_undefined(vcpu);
  55         return 1;
  56 }
  57
  58 /**
  59  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
  60  *                  instruction executed by a guest
  61  *
  62  * @vcpu:       the vcpu pointer
  63  *
  64  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  65  * decides to.
  66  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  67  * world-switches and schedule other host processes until there is an
  68  * incoming IRQ or FIQ to the VM.
  69  */
  70 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  71 {
  72         if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
  73                 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
  74                 kvm_vcpu_on_spin(vcpu);
  75         } else {
  76                 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
  77                 kvm_vcpu_block(vcpu);
  78         }
  79
  80         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  81
  82         return 1;
  83 }
  84
  85 /**
  86  * kvm_handle_guest_debug - handle a debug exception instruction
  87  *
  88  * @vcpu:       the vcpu pointer
  89  * @run:        access to the kvm_run structure for results
  90  *
  91  * We route all debug exceptions through the same handler. If both the
  92  * guest and host are using the same debug facilities it will be up to
  93  * userspace to re-inject the correct exception for guest delivery.
  94  *
  95  * @return: 0 (while setting run->exit_reason), -1 for error
  96  */
  97 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
  98 {
  99         u32 hsr = kvm_vcpu_get_hsr(vcpu);
 100         int ret = 0;
 101
 102         run->exit_reason = KVM_EXIT_DEBUG;
 103         run->debug.arch.hsr = hsr;
 104
 105         switch (hsr >> ESR_ELx_EC_SHIFT) {
 106         case ESR_ELx_EC_WATCHPT_LOW:
 107                 run->debug.arch.far = vcpu->arch.fault.far_el2;
 108                 /* fall through */
 109         case ESR_ELx_EC_SOFTSTP_LOW:
 110         case ESR_ELx_EC_BREAKPT_LOW:
 111         case ESR_ELx_EC_BKPT32:
 112         case ESR_ELx_EC_BRK64:
 113                 break;
 114         default:
 115                 kvm_err("%s: un-handled case hsr: %#08x\n",
 116                         __func__, (unsigned int) hsr);
 117                 ret = -1;
 118                 break;
 119         }
 120
 121         return ret;
 122 }
 123
 124 static exit_handle_fn arm_exit_handlers[] = {
 125         [ESR_ELx_EC_WFx]        = kvm_handle_wfx,
 126         [ESR_ELx_EC_CP15_32]    = kvm_handle_cp15_32,
 127         [ESR_ELx_EC_CP15_64]    = kvm_handle_cp15_64,
 128         [ESR_ELx_EC_CP14_MR]    = kvm_handle_cp14_32,
 129         [ESR_ELx_EC_CP14_LS]    = kvm_handle_cp14_load_store,
 130         [ESR_ELx_EC_CP14_64]    = kvm_handle_cp14_64,
 131         [ESR_ELx_EC_HVC32]      = handle_hvc,
 132         [ESR_ELx_EC_SMC32]      = handle_smc,
 133         [ESR_ELx_EC_HVC64]      = handle_hvc,
 134         [ESR_ELx_EC_SMC64]      = handle_smc,
 135         [ESR_ELx_EC_SYS64]      = kvm_handle_sys_reg,
 136         [ESR_ELx_EC_IABT_LOW]   = kvm_handle_guest_abort,
 137         [ESR_ELx_EC_DABT_LOW]   = kvm_handle_guest_abort,
 138         [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
 139         [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
 140         [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
 141         [ESR_ELx_EC_BKPT32]     = kvm_handle_guest_debug,
 142         [ESR_ELx_EC_BRK64]      = kvm_handle_guest_debug,
 143 };
 144
 145 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 146 {
 147         u32 hsr = kvm_vcpu_get_hsr(vcpu);
 148         u8 hsr_ec = hsr >> ESR_ELx_EC_SHIFT;
 149
 150         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 151             !arm_exit_handlers[hsr_ec]) {
 152                 kvm_err("Unknown exception class: hsr: %#08x -- %s\n",
 153                         hsr, esr_get_class_string(hsr));
 154                 BUG();
 155         }
 156
 157         return arm_exit_handlers[hsr_ec];
 158 }
 159
 160 /*
 161  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 162  * proper exit to userspace.
 163  */
 164 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 165                        int exception_index)
 166 {
 167         exit_handle_fn exit_handler;
 168
 169         switch (exception_index) {
 170         case ARM_EXCEPTION_IRQ:
 171                 return 1;
 172         case ARM_EXCEPTION_TRAP:
 173                 /*
 174                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 175                  * that fail their condition code check"
 176                  */
 177                 if (!kvm_condition_valid(vcpu)) {
 178                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 179                         return 1;
 180                 }
 181
 182                 exit_handler = kvm_get_exit_handler(vcpu);
 183
 184                 return exit_handler(vcpu, run);
 185         default:
 186                 kvm_pr_unimpl("Unsupported exception type: %d",
 187                               exception_index);
 188                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 189                 return 0;
 190         }
 191 }