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
  28 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  29
  30 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  31 {
  32         /*
  33          * Guest called HVC instruction:
  34          * Let it know we don't want that by injecting an undefined exception.
  35          */
  36         kvm_debug("hvc: %x (at %08lx)", kvm_vcpu_get_hsr(vcpu) & ((1 << 16) - 1),
  37                   *vcpu_pc(vcpu));
  38         kvm_debug("         HSR: %8x", kvm_vcpu_get_hsr(vcpu));
  39         kvm_inject_undefined(vcpu);
  40         return 1;
  41 }
  42
  43 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  44 {
  45         /* We don't support SMC; don't do that. */
  46         kvm_debug("smc: at %08lx", *vcpu_pc(vcpu));
  47         kvm_inject_undefined(vcpu);
  48         return 1;
  49 }
  50
  51 /**
  52  * kvm_handle_wfi - handle a wait-for-interrupts instruction executed by a guest
  53  * @vcpu:       the vcpu pointer
  54  *
  55  * Simply call kvm_vcpu_block(), which will halt execution of
  56  * world-switches and schedule other host processes until there is an
  57  * incoming IRQ or FIQ to the VM.
  58  */
  59 static int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)
  60 {
  61         kvm_vcpu_block(vcpu);
  62         return 1;
  63 }
  64
  65 static exit_handle_fn arm_exit_handlers[] = {
  66         [ESR_EL2_EC_WFI]        = kvm_handle_wfi,
  67         [ESR_EL2_EC_HVC64]      = handle_hvc,
  68         [ESR_EL2_EC_SMC64]      = handle_smc,
  69         [ESR_EL2_EC_SYS64]      = kvm_handle_sys_reg,
  70         [ESR_EL2_EC_IABT]       = kvm_handle_guest_abort,
  71         [ESR_EL2_EC_DABT]       = kvm_handle_guest_abort,
  72 };
  73
  74 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
  75 {
  76         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
  77
  78         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
  79             !arm_exit_handlers[hsr_ec]) {
  80                 kvm_err("Unkown exception class: hsr: %#08x\n",
  81                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
  82                 BUG();
  83         }
  84
  85         return arm_exit_handlers[hsr_ec];
  86 }
  87
  88 /*
  89  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
  90  * proper exit to userspace.
  91  */
  92 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
  93                        int exception_index)
  94 {
  95         exit_handle_fn exit_handler;
  96
  97         switch (exception_index) {
  98         case ARM_EXCEPTION_IRQ:
  99                 return 1;
 100         case ARM_EXCEPTION_TRAP:
 101                 /*
 102                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 103                  * that fail their condition code check"
 104                  */
 105                 if (!kvm_condition_valid(vcpu)) {
 106                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 107                         return 1;
 108                 }
 109
 110                 exit_handler = kvm_get_exit_handler(vcpu);
 111
 112                 return exit_handler(vcpu, run);
 113         default:
 114                 kvm_pr_unimpl("Unsupported exception type: %d",
 115                               exception_index);
 116                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 117                 return 0;
 118         }
 119 }