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_asm.h> 27 #include <asm/kvm_coproc.h> 28 #include <asm/kvm_emulate.h> 29 #include <asm/kvm_mmu.h> 30 #include <asm/kvm_psci.h> 31 32 #define CREATE_TRACE_POINTS 33 #include "trace.h" 34 35 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *); 36 37 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) 38 { 39 int ret; 40 41 trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0), 42 kvm_vcpu_hvc_get_imm(vcpu)); 43 vcpu->stat.hvc_exit_stat++; 44 45 ret = kvm_psci_call(vcpu); 46 if (ret < 0) { 47 kvm_inject_undefined(vcpu); 48 return 1; 49 } 50 51 return ret; 52 } 53 54 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) 55 { 56 kvm_inject_undefined(vcpu); 57 return 1; 58 } 59 60 /** 61 * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event 62 * instruction executed by a guest 63 * 64 * @vcpu: the vcpu pointer 65 * 66 * WFE: Yield the CPU and come back to this vcpu when the scheduler 67 * decides to. 68 * WFI: Simply call kvm_vcpu_block(), which will halt execution of 69 * world-switches and schedule other host processes until there is an 70 * incoming IRQ or FIQ to the VM. 71 */ 72 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) 73 { 74 if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) { 75 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true); 76 vcpu->stat.wfe_exit_stat++; 77 kvm_vcpu_on_spin(vcpu); 78 } else { 79 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false); 80 vcpu->stat.wfi_exit_stat++; 81 kvm_vcpu_block(vcpu); 82 } 83 84 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 85 86 return 1; 87 } 88 89 /** 90 * kvm_handle_guest_debug - handle a debug exception instruction 91 * 92 * @vcpu: the vcpu pointer 93 * @run: access to the kvm_run structure for results 94 * 95 * We route all debug exceptions through the same handler. If both the 96 * guest and host are using the same debug facilities it will be up to 97 * userspace to re-inject the correct exception for guest delivery. 98 * 99 * @return: 0 (while setting run->exit_reason), -1 for error 100 */ 101 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) 102 { 103 u32 hsr = kvm_vcpu_get_hsr(vcpu); 104 int ret = 0; 105 106 run->exit_reason = KVM_EXIT_DEBUG; 107 run->debug.arch.hsr = hsr; 108 109 switch (ESR_ELx_EC(hsr)) { 110 case ESR_ELx_EC_WATCHPT_LOW: 111 run->debug.arch.far = vcpu->arch.fault.far_el2; 112 /* fall through */ 113 case ESR_ELx_EC_SOFTSTP_LOW: 114 case ESR_ELx_EC_BREAKPT_LOW: 115 case ESR_ELx_EC_BKPT32: 116 case ESR_ELx_EC_BRK64: 117 break; 118 default: 119 kvm_err("%s: un-handled case hsr: %#08x\n", 120 __func__, (unsigned int) hsr); 121 ret = -1; 122 break; 123 } 124 125 return ret; 126 } 127 128 static exit_handle_fn arm_exit_handlers[] = { 129 [ESR_ELx_EC_WFx] = kvm_handle_wfx, 130 [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, 131 [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, 132 [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32, 133 [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store, 134 [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64, 135 [ESR_ELx_EC_HVC32] = handle_hvc, 136 [ESR_ELx_EC_SMC32] = handle_smc, 137 [ESR_ELx_EC_HVC64] = handle_hvc, 138 [ESR_ELx_EC_SMC64] = handle_smc, 139 [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, 140 [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, 141 [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, 142 [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, 143 [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug, 144 [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, 145 [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, 146 [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, 147 }; 148 149 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) 150 { 151 u32 hsr = kvm_vcpu_get_hsr(vcpu); 152 u8 hsr_ec = ESR_ELx_EC(hsr); 153 154 if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) || 155 !arm_exit_handlers[hsr_ec]) { 156 kvm_err("Unknown exception class: hsr: %#08x -- %s\n", 157 hsr, esr_get_class_string(hsr)); 158 BUG(); 159 } 160 161 return arm_exit_handlers[hsr_ec]; 162 } 163 164 /* 165 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on 166 * proper exit to userspace. 167 */ 168 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, 169 int exception_index) 170 { 171 exit_handle_fn exit_handler; 172 173 if (ARM_SERROR_PENDING(exception_index)) { 174 u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); 175 176 /* 177 * HVC/SMC already have an adjusted PC, which we need 178 * to correct in order to return to after having 179 * injected the SError. 180 */ 181 if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 || 182 hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) { 183 u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2; 184 *vcpu_pc(vcpu) -= adj; 185 } 186 187 kvm_inject_vabt(vcpu); 188 return 1; 189 } 190 191 exception_index = ARM_EXCEPTION_CODE(exception_index); 192 193 switch (exception_index) { 194 case ARM_EXCEPTION_IRQ: 195 return 1; 196 case ARM_EXCEPTION_EL1_SERROR: 197 kvm_inject_vabt(vcpu); 198 return 1; 199 case ARM_EXCEPTION_TRAP: 200 /* 201 * See ARM ARM B1.14.1: "Hyp traps on instructions 202 * that fail their condition code check" 203 */ 204 if (!kvm_condition_valid(vcpu)) { 205 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 206 return 1; 207 } 208 209 exit_handler = kvm_get_exit_handler(vcpu); 210 211 return exit_handler(vcpu, run); 212 case ARM_EXCEPTION_HYP_GONE: 213 /* 214 * EL2 has been reset to the hyp-stub. This happens when a guest 215 * is pre-empted by kvm_reboot()'s shutdown call. 216 */ 217 run->exit_reason = KVM_EXIT_FAIL_ENTRY; 218 return 0; 219 default: 220 kvm_pr_unimpl("Unsupported exception type: %d", 221 exception_index); 222 run->exit_reason = KVM_EXIT_INTERNAL_ERROR; 223 return 0; 224 } 225 } 226