arch/arm/kvm/handle_exit.c

   1 /*
   2  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   3  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17  */
  18
  19 #include <linux/kvm.h>
  20 #include <linux/kvm_host.h>
  21 #include <asm/kvm_emulate.h>
  22 #include <asm/kvm_coproc.h>
  23 #include <asm/kvm_mmu.h>
  24 #include <asm/kvm_psci.h>
  25 #include <trace/events/kvm.h>
  26
  27 #include "trace.h"
  28
  29 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
  30
  31 static int handle_svc_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  32 {
  33         /* SVC called from Hyp mode should never get here */
  34         kvm_debug("SVC called from Hyp mode shouldn't go here\n");
  35         BUG();
  36         return -EINVAL; /* Squash warning */
  37 }
  38
  39 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  40 {
  41         trace_kvm_hvc(*vcpu_pc(vcpu), *vcpu_reg(vcpu, 0),
  42                       kvm_vcpu_hvc_get_imm(vcpu));
  43
  44         if (kvm_psci_call(vcpu))
  45                 return 1;
  46
  47         kvm_inject_undefined(vcpu);
  48         return 1;
  49 }
  50
  51 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run)
  52 {
  53         kvm_inject_undefined(vcpu);
  54         return 1;
  55 }
  56
  57 static int handle_pabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  58 {
  59         /* The hypervisor should never cause aborts */
  60         kvm_err("Prefetch Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  61                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  62         return -EFAULT;
  63 }
  64
  65 static int handle_dabt_hyp(struct kvm_vcpu *vcpu, struct kvm_run *run)
  66 {
  67         /* This is either an error in the ws. code or an external abort */
  68         kvm_err("Data Abort taken from Hyp mode at %#08lx (HSR: %#08x)\n",
  69                 kvm_vcpu_get_hfar(vcpu), kvm_vcpu_get_hsr(vcpu));
  70         return -EFAULT;
  71 }
  72
  73 /**
  74  * kvm_handle_wfx - handle a WFI or WFE instructions trapped in guests
  75  * @vcpu:       the vcpu pointer
  76  * @run:        the kvm_run structure pointer
  77  *
  78  * WFE: Yield the CPU and come back to this vcpu when the scheduler
  79  * decides to.
  80  * WFI: Simply call kvm_vcpu_block(), which will halt execution of
  81  * world-switches and schedule other host processes until there is an
  82  * incoming IRQ or FIQ to the VM.
  83  */
  84 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run)
  85 {
  86         trace_kvm_wfi(*vcpu_pc(vcpu));
  87         if (kvm_vcpu_get_hsr(vcpu) & HSR_WFI_IS_WFE)
  88                 kvm_vcpu_on_spin(vcpu);
  89         else
  90                 kvm_vcpu_block(vcpu);
  91
  92         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
  93
  94         return 1;
  95 }
  96
  97 static exit_handle_fn arm_exit_handlers[] = {
  98         [HSR_EC_WFI]            = kvm_handle_wfx,
  99         [HSR_EC_CP15_32]        = kvm_handle_cp15_32,
 100         [HSR_EC_CP15_64]        = kvm_handle_cp15_64,
 101         [HSR_EC_CP14_MR]        = kvm_handle_cp14_access,
 102         [HSR_EC_CP14_LS]        = kvm_handle_cp14_load_store,
 103         [HSR_EC_CP14_64]        = kvm_handle_cp14_access,
 104         [HSR_EC_CP_0_13]        = kvm_handle_cp_0_13_access,
 105         [HSR_EC_CP10_ID]        = kvm_handle_cp10_id,
 106         [HSR_EC_SVC_HYP]        = handle_svc_hyp,
 107         [HSR_EC_HVC]            = handle_hvc,
 108         [HSR_EC_SMC]            = handle_smc,
 109         [HSR_EC_IABT]           = kvm_handle_guest_abort,
 110         [HSR_EC_IABT_HYP]       = handle_pabt_hyp,
 111         [HSR_EC_DABT]           = kvm_handle_guest_abort,
 112         [HSR_EC_DABT_HYP]       = handle_dabt_hyp,
 113 };
 114
 115 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
 116 {
 117         u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
 118
 119         if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) ||
 120             !arm_exit_handlers[hsr_ec]) {
 121                 kvm_err("Unknown exception class: hsr: %#08x\n",
 122                         (unsigned int)kvm_vcpu_get_hsr(vcpu));
 123                 BUG();
 124         }
 125
 126         return arm_exit_handlers[hsr_ec];
 127 }
 128
 129 /*
 130  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
 131  * proper exit to userspace.
 132  */
 133 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 134                        int exception_index)
 135 {
 136         exit_handle_fn exit_handler;
 137
 138         switch (exception_index) {
 139         case ARM_EXCEPTION_IRQ:
 140                 return 1;
 141         case ARM_EXCEPTION_UNDEFINED:
 142                 kvm_err("Undefined exception in Hyp mode at: %#08lx\n",
 143                         kvm_vcpu_get_hyp_pc(vcpu));
 144                 BUG();
 145                 panic("KVM: Hypervisor undefined exception!\n");
 146         case ARM_EXCEPTION_DATA_ABORT:
 147         case ARM_EXCEPTION_PREF_ABORT:
 148         case ARM_EXCEPTION_HVC:
 149                 /*
 150                  * See ARM ARM B1.14.1: "Hyp traps on instructions
 151                  * that fail their condition code check"
 152                  */
 153                 if (!kvm_condition_valid(vcpu)) {
 154                         kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 155                         return 1;
 156                 }
 157
 158                 exit_handler = kvm_get_exit_handler(vcpu);
 159
 160                 return exit_handler(vcpu, run);
 161         default:
 162                 kvm_pr_unimpl("Unsupported exception type: %d",
 163                               exception_index);
 164                 run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 165                 return 0;
 166         }
 167 }