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_asm.h>
  27 #include <asm/kvm_coproc.h>
  28 #include <asm/kvm_emulate.h>
  29 #include <asm/kvm_mmu.h>
  30 #include <asm/kvm_psci.h>
  31
  32 #define CREATE_TRACE_POINTS
  33 #include "trace.h"
  34
  35 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  36
  37 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  38 {
  39         int ret;
  40
  41         trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0),
  42                             kvm_vcpu_hvc_get_imm(vcpu));
  43
  44         ret = kvm_psci_call(vcpu);
  45         if (ret < 0) {
  46                 kvm_inject_undefined(vcpu);
  47                 return 1;
  48         }
  49
  50         return ret;
  51 }
  52
  53 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  54 {
  55         kvm_inject_undefined(vcpu);
  56         return 1;
  57 }
  58
  59 /**
  60  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
  61  *                  instruction executed by a guest
  62  *
  63  * @vcpu:       the vcpu pointer
  64  *
  65  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  66  * decides to.
  67  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  68  * world-switches and schedule other host processes until there is an
  69  * incoming IRQ or FIQ to the VM.
  70  */
  71 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  72 {
  73         if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) {
  74                 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true);
  75                 kvm_vcpu_on_spin(vcpu);
  76         } else {
  77                 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false);
  78                 kvm_vcpu_block(vcpu);
  79         }
  80
  81         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  82
  83         return 1;
  84 }
  85
  86 /**
  87  * kvm_handle_guest_debug - handle a debug exception instruction
  88  *
  89  * @vcpu:       the vcpu pointer
  90  * @run:        access to the kvm_run structure for results
  91  *
  92  * We route all debug exceptions through the same handler. If both the
  93  * guest and host are using the same debug facilities it will be up to
  94  * userspace to re-inject the correct exception for guest delivery.
  95  *
  96  * @return: 0 (while setting run->exit_reason), -1 for error
  97  */
  98 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run)
  99 {
 100         u32 hsr = kvm_vcpu_get_hsr(vcpu);
 101         int ret = 0;
 102
 103         run->exit_reason = KVM_EXIT_DEBUG;
 104         run->debug.arch.hsr = hsr;
 105
 106         switch (hsr >> ESR_ELx_EC_SHIFT) {
 107         case ESR_ELx_EC_WATCHPT_LOW:
 108                 run->debug.arch.far = vcpu->arch.fault.far_el2;
 109                 /* fall through */
 110         case ESR_ELx_EC_SOFTSTP_LOW:
 111         case ESR_ELx_EC_BREAKPT_LOW:
 112         case ESR_ELx_EC_BKPT32:
 113         case ESR_ELx_EC_BRK64:
 114                 break;
 115         default:
 116                 kvm_err("%s: un-handled case hsr: %#08x\n",
 117                         __func__, (unsigned int) hsr);
 118                 ret = -1;
 119                 break;
 120         }
 121
 122         return ret;
 123 }
 124
 125 static exit_handle_fn arm_exit_handlers[] = {
 126         [ESR_ELx_EC_WFx]        = kvm_handle_wfx,
 127         [ESR_ELx_EC_CP15_32]    = kvm_handle_cp15_32,
 128         [ESR_ELx_EC_CP15_64]    = kvm_handle_cp15_64,
 129         [ESR_ELx_EC_CP14_MR]    = kvm_handle_cp14_32,
 130         [ESR_ELx_EC_CP14_LS]    = kvm_handle_cp14_load_store,
 131         [ESR_ELx_EC_CP14_64]    = kvm_handle_cp14_64,
 132         [ESR_ELx_EC_HVC32]      = handle_hvc,
 133         [ESR_ELx_EC_SMC32]      = handle_smc,
 134         [ESR_ELx_EC_HVC64]      = handle_hvc,
 135         [ESR_ELx_EC_SMC64]      = handle_smc,
 136         [ESR_ELx_EC_SYS64]      = kvm_handle_sys_reg,
 137         [ESR_ELx_EC_IABT_LOW]   = kvm_handle_guest_abort,
 138         [ESR_ELx_EC_DABT_LOW]   = kvm_handle_guest_abort,
 139         [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,
 140         [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug,
 141         [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
 142         [ESR_ELx_EC_BKPT32]     = kvm_handle_guest_debug,
 143         [ESR_ELx_EC_BRK64]      = kvm_handle_guest_debug,
 144 };
 145
 146 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 147 {
 148         u32 hsr = kvm_vcpu_get_hsr(vcpu);
 149         u8 hsr_ec = hsr >> ESR_ELx_EC_SHIFT;
 150
 151         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 152             !arm_exit_handlers[hsr_ec]) {
 153                 kvm_err("Unknown exception class: hsr: %#08x -- %s\n",
 154                         hsr, esr_get_class_string(hsr));
 155                 BUG();
 156         }
 157
 158         return arm_exit_handlers[hsr_ec];
 159 }
 160
 161 /*
 162  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 163  * proper exit to userspace.
 164  */
 165 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 166                        int exception_index)
 167 {
 168         exit_handle_fn exit_handler;
 169
 170         switch (exception_index) {
 171         case ARM_EXCEPTION_IRQ:
 172                 return 1;
 173         case ARM_EXCEPTION_TRAP:
 174                 /*
 175                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 176                  * that fail their condition code check"
 177                  */
 178                 if (!kvm_condition_valid(vcpu)) {
 179                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 180                         return 1;
 181                 }
 182
 183                 exit_handler = kvm_get_exit_handler(vcpu);
 184
 185                 return exit_handler(vcpu, run);
 186         default:
 187                 kvm_pr_unimpl("Unsupported exception type: %d",
 188                               exception_index);
 189                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 190                 return 0;
 191         }
 192 }