kernel/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 static exit_handle_fn arm_exit_handlers[] = {
  86         [ESR_ELx_EC_WFx]        = kvm_handle_wfx,
  87         [ESR_ELx_EC_CP15_32]    = kvm_handle_cp15_32,
  88         [ESR_ELx_EC_CP15_64]    = kvm_handle_cp15_64,
  89         [ESR_ELx_EC_CP14_MR]    = kvm_handle_cp14_32,
  90         [ESR_ELx_EC_CP14_LS]    = kvm_handle_cp14_load_store,
  91         [ESR_ELx_EC_CP14_64]    = kvm_handle_cp14_64,
  92         [ESR_ELx_EC_HVC32]      = handle_hvc,
  93         [ESR_ELx_EC_SMC32]      = handle_smc,
  94         [ESR_ELx_EC_HVC64]      = handle_hvc,
  95         [ESR_ELx_EC_SMC64]      = handle_smc,
  96         [ESR_ELx_EC_SYS64]      = kvm_handle_sys_reg,
  97         [ESR_ELx_EC_IABT_LOW]   = kvm_handle_guest_abort,
  98         [ESR_ELx_EC_DABT_LOW]   = kvm_handle_guest_abort,
  99 };
 100
 101 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 102 {
 103         u32 hsr = kvm_vcpu_get_hsr(vcpu);
 104         u8 hsr_ec = hsr >> ESR_ELx_EC_SHIFT;
 105
 106         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 107             !arm_exit_handlers[hsr_ec]) {
 108                 kvm_err("Unknown exception class: hsr: %#08x -- %s\n",
 109                         hsr, esr_get_class_string(hsr));
 110                 BUG();
 111         }
 112
 113         return arm_exit_handlers[hsr_ec];
 114 }
 115
 116 /*
 117  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 118  * proper exit to userspace.
 119  */
 120 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 121                        int exception_index)
 122 {
 123         exit_handle_fn exit_handler;
 124
 125         switch (exception_index) {
 126         case ARM_EXCEPTION_IRQ:
 127                 return 1;
 128         case ARM_EXCEPTION_TRAP:
 129                 /*
 130                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 131                  * that fail their condition code check"
 132                  */
 133                 if (!kvm_condition_valid(vcpu)) {
 134                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 135                         return 1;
 136                 }
 137
 138                 exit_handler = kvm_get_exit_handler(vcpu);
 139
 140                 return exit_handler(vcpu, run);
 141         default:
 142                 kvm_pr_unimpl("Unsupported exception type: %d",
 143                               exception_index);
 144                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 145                 return 0;
 146         }
 147 }