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 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  32
  33 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  34 {
  35         int ret;
  36
  37         ret = kvm_psci_call(vcpu);
  38         if (ret < 0) {
  39                 kvm_inject_undefined(vcpu);
  40                 return 1;
  41         }
  42
  43         return ret;
  44 }
  45
  46 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  47 {
  48         kvm_inject_undefined(vcpu);
  49         return 1;
  50 }
  51
  52 /**
  53  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
  54  *                  instruction executed by a guest
  55  *
  56  * @vcpu:       the vcpu pointer
  57  *
  58  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  59  * decides to.
  60  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  61  * world-switches and schedule other host processes until there is an
  62  * incoming IRQ or FIQ to the VM.
  63  */
  64 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  65 {
  66         if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE)
  67                 kvm_vcpu_on_spin(vcpu);
  68         else
  69                 kvm_vcpu_block(vcpu);
  70
  71         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  72
  73         return 1;
  74 }
  75
  76 static exit_handle_fn arm_exit_handlers[] = {
  77         [ESR_ELx_EC_WFx]        = kvm_handle_wfx,
  78         [ESR_ELx_EC_CP15_32]    = kvm_handle_cp15_32,
  79         [ESR_ELx_EC_CP15_64]    = kvm_handle_cp15_64,
  80         [ESR_ELx_EC_CP14_MR]    = kvm_handle_cp14_32,
  81         [ESR_ELx_EC_CP14_LS]    = kvm_handle_cp14_load_store,
  82         [ESR_ELx_EC_CP14_64]    = kvm_handle_cp14_64,
  83         [ESR_ELx_EC_HVC32]      = handle_hvc,
  84         [ESR_ELx_EC_SMC32]      = handle_smc,
  85         [ESR_ELx_EC_HVC64]      = handle_hvc,
  86         [ESR_ELx_EC_SMC64]      = handle_smc,
  87         [ESR_ELx_EC_SYS64]      = kvm_handle_sys_reg,
  88         [ESR_ELx_EC_IABT_LOW]   = kvm_handle_guest_abort,
  89         [ESR_ELx_EC_DABT_LOW]   = kvm_handle_guest_abort,
  90 };
  91
  92 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
  93 {
  94         u32 hsr = kvm_vcpu_get_hsr(vcpu);
  95         u8 hsr_ec = hsr >> ESR_ELx_EC_SHIFT;
  96
  97         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
  98             !arm_exit_handlers[hsr_ec]) {
  99                 kvm_err("Unknown exception class: hsr: %#08x -- %s\n",
 100                         hsr, esr_get_class_string(hsr));
 101                 BUG();
 102         }
 103
 104         return arm_exit_handlers[hsr_ec];
 105 }
 106
 107 /*
 108  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 109  * proper exit to userspace.
 110  */
 111 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 112                        int exception_index)
 113 {
 114         exit_handle_fn exit_handler;
 115
 116         switch (exception_index) {
 117         case ARM_EXCEPTION_IRQ:
 118                 return 1;
 119         case ARM_EXCEPTION_TRAP:
 120                 /*
 121                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 122                  * that fail their condition code check"
 123                  */
 124                 if (!kvm_condition_valid(vcpu)) {
 125                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 126                         return 1;
 127                 }
 128
 129                 exit_handler = kvm_get_exit_handler(vcpu);
 130
 131                 return exit_handler(vcpu, run);
 132         default:
 133                 kvm_pr_unimpl("Unsupported exception type: %d",
 134                               exception_index);
 135                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 136                 return 0;
 137         }
 138 }