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         if (kvm_psci_call(vcpu))
  34                 return 1;
  35
  36         kvm_inject_undefined(vcpu);
  37         return 1;
  38 }
  39
  40 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  41 {
  42         if (kvm_psci_call(vcpu))
  43                 return 1;
  44
  45         kvm_inject_undefined(vcpu);
  46         return 1;
  47 }
  48
  49 /**
  50  * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event
  51  *                  instruction executed by a guest
  52  *
  53  * @vcpu:       the vcpu pointer
  54  *
  55  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  56  * decides to.
  57  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  58  * world-switches and schedule other host processes until there is an
  59  * incoming IRQ or FIQ to the VM.
  60  */
  61 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  62 {
  63         if (kvm_vcpu_get_hsr(vcpu) & ESR_EL2_EC_WFI_ISS_WFE)
  64                 kvm_vcpu_on_spin(vcpu);
  65         else
  66                 kvm_vcpu_block(vcpu);
  67
  68         return 1;
  69 }
  70
  71 static exit_handle_fn arm_exit_handlers[] = {
  72         [ESR_EL2_EC_WFI]        = kvm_handle_wfx,
  73         [ESR_EL2_EC_CP15_32]    = kvm_handle_cp15_32,
  74         [ESR_EL2_EC_CP15_64]    = kvm_handle_cp15_64,
  75         [ESR_EL2_EC_CP14_MR]    = kvm_handle_cp14_access,
  76         [ESR_EL2_EC_CP14_LS]    = kvm_handle_cp14_load_store,
  77         [ESR_EL2_EC_CP14_64]    = kvm_handle_cp14_access,
  78         [ESR_EL2_EC_HVC32]      = handle_hvc,
  79         [ESR_EL2_EC_SMC32]      = handle_smc,
  80         [ESR_EL2_EC_HVC64]      = handle_hvc,
  81         [ESR_EL2_EC_SMC64]      = handle_smc,
  82         [ESR_EL2_EC_SYS64]      = kvm_handle_sys_reg,
  83         [ESR_EL2_EC_IABT]       = kvm_handle_guest_abort,
  84         [ESR_EL2_EC_DABT]       = kvm_handle_guest_abort,
  85 };
  86
  87 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
  88 {
  89         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
  90
  91         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
  92             !arm_exit_handlers[hsr_ec]) {
  93                 kvm_err("Unkown exception class: hsr: %#08x\n",
  94                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
  95                 BUG();
  96         }
  97
  98         return arm_exit_handlers[hsr_ec];
  99 }
 100
 101 /*
 102  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 103  * proper exit to userspace.
 104  */
 105 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 106                        int exception_index)
 107 {
 108         exit_handle_fn exit_handler;
 109
 110         switch (exception_index) {
 111         case ARM_EXCEPTION_IRQ:
 112                 return 1;
 113         case ARM_EXCEPTION_TRAP:
 114                 /*
 115                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 116                  * that fail their condition code check"
 117                  */
 118                 if (!kvm_condition_valid(vcpu)) {
 119                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 120                         return 1;
 121                 }
 122
 123                 exit_handler = kvm_get_exit_handler(vcpu);
 124
 125                 return exit_handler(vcpu, run);
 126         default:
 127                 kvm_pr_unimpl("Unsupported exception type: %d",
 128                               exception_index);
 129                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 130                 return 0;
 131         }
 132 }