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 #include <asm/kvm_emulate.h>
  25 #include <asm/kvm_coproc.h>
  26 #include <asm/kvm_mmu.h>
  27 #include <asm/kvm_psci.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         ret = kvm_psci_call(vcpu);
  36         if (ret < 0) {
  37                 kvm_inject_undefined(vcpu);
  38                 return 1;
  39         }
  40
  41         return ret;
  42 }
  43
  44 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  45 {
  46         kvm_inject_undefined(vcpu);
  47         return 1;
  48 }
  49
  50 /**
  51  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
  52  *                  instruction executed by a guest
  53  *
  54  * @vcpu:       the vcpu pointer
  55  *
  56  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  57  * decides to.
  58  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  59  * world-switches and schedule other host processes until there is an
  60  * incoming IRQ or FIQ to the VM.
  61  */
  62 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  63 {
  64         if (kvm_vcpu_get_hsr(vcpu) & ESR_EL2_EC_WFI_ISS_WFE)
  65                 kvm_vcpu_on_spin(vcpu);
  66         else
  67                 kvm_vcpu_block(vcpu);
  68
  69         return 1;
  70 }
  71
  72 static exit_handle_fn arm_exit_handlers[] = {
  73         [ESR_EL2_EC_WFI]        = kvm_handle_wfx,
  74         [ESR_EL2_EC_CP15_32]    = kvm_handle_cp15_32,
  75         [ESR_EL2_EC_CP15_64]    = kvm_handle_cp15_64,
  76         [ESR_EL2_EC_CP14_MR]    = kvm_handle_cp14_access,
  77         [ESR_EL2_EC_CP14_LS]    = kvm_handle_cp14_load_store,
  78         [ESR_EL2_EC_CP14_64]    = kvm_handle_cp14_access,
  79         [ESR_EL2_EC_HVC32]      = handle_hvc,
  80         [ESR_EL2_EC_SMC32]      = handle_smc,
  81         [ESR_EL2_EC_HVC64]      = handle_hvc,
  82         [ESR_EL2_EC_SMC64]      = handle_smc,
  83         [ESR_EL2_EC_SYS64]      = kvm_handle_sys_reg,
  84         [ESR_EL2_EC_IABT]       = kvm_handle_guest_abort,
  85         [ESR_EL2_EC_DABT]       = kvm_handle_guest_abort,
  86 };
  87
  88 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
  89 {
  90         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
  91
  92         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
  93             !arm_exit_handlers[hsr_ec]) {
  94                 kvm_err("Unknown exception class: hsr: %#08x\n",
  95                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
  96                 BUG();
  97         }
  98
  99         return arm_exit_handlers[hsr_ec];
 100 }
 101
 102 /*
 103  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 104  * proper exit to userspace.
 105  */
 106 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 107                        int exception_index)
 108 {
 109         exit_handle_fn exit_handler;
 110
 111         switch (exception_index) {
 112         case ARM_EXCEPTION_IRQ:
 113                 return 1;
 114         case ARM_EXCEPTION_TRAP:
 115                 /*
 116                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 117                  * that fail their condition code check"
 118                  */
 119                 if (!kvm_condition_valid(vcpu)) {
 120                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 121                         return 1;
 122                 }
 123
 124                 exit_handler = kvm_get_exit_handler(vcpu);
 125
 126                 return exit_handler(vcpu, run);
 127         default:
 128                 kvm_pr_unimpl("Unsupported exception type: %d",
 129                               exception_index);
 130                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 131                 return 0;
 132         }
 133 }