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 #include <asm/debug-monitors.h> 32 33 #define CREATE_TRACE_POINTS 34 #include "trace.h" 35 36 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *); 37 38 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) 39 { 40 int ret; 41 42 trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0), 43 kvm_vcpu_hvc_get_imm(vcpu)); 44 vcpu->stat.hvc_exit_stat++; 45 46 ret = kvm_psci_call(vcpu); 47 if (ret < 0) { 48 kvm_inject_undefined(vcpu); 49 return 1; 50 } 51 52 return ret; 53 } 54 55 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) 56 { 57 kvm_inject_undefined(vcpu); 58 return 1; 59 } 60 61 /* 62 * Guest access to FP/ASIMD registers are routed to this handler only 63 * when the system doesn't support FP/ASIMD. 64 */ 65 static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run) 66 { 67 kvm_inject_undefined(vcpu); 68 return 1; 69 } 70 71 /** 72 * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event 73 * instruction executed by a guest 74 * 75 * @vcpu: the vcpu pointer 76 * 77 * WFE: Yield the CPU and come back to this vcpu when the scheduler 78 * decides to. 79 * WFI: Simply call kvm_vcpu_block(), which will halt execution of 80 * world-switches and schedule other host processes until there is an 81 * incoming IRQ or FIQ to the VM. 82 */ 83 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) 84 { 85 if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) { 86 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true); 87 vcpu->stat.wfe_exit_stat++; 88 kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu)); 89 } else { 90 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false); 91 vcpu->stat.wfi_exit_stat++; 92 kvm_vcpu_block(vcpu); 93 kvm_clear_request(KVM_REQ_UNHALT, vcpu); 94 } 95 96 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 97 98 return 1; 99 } 100 101 /** 102 * kvm_handle_guest_debug - handle a debug exception instruction 103 * 104 * @vcpu: the vcpu pointer 105 * @run: access to the kvm_run structure for results 106 * 107 * We route all debug exceptions through the same handler. If both the 108 * guest and host are using the same debug facilities it will be up to 109 * userspace to re-inject the correct exception for guest delivery. 110 * 111 * @return: 0 (while setting run->exit_reason), -1 for error 112 */ 113 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) 114 { 115 u32 hsr = kvm_vcpu_get_hsr(vcpu); 116 int ret = 0; 117 118 run->exit_reason = KVM_EXIT_DEBUG; 119 run->debug.arch.hsr = hsr; 120 121 switch (ESR_ELx_EC(hsr)) { 122 case ESR_ELx_EC_WATCHPT_LOW: 123 run->debug.arch.far = vcpu->arch.fault.far_el2; 124 /* fall through */ 125 case ESR_ELx_EC_SOFTSTP_LOW: 126 case ESR_ELx_EC_BREAKPT_LOW: 127 case ESR_ELx_EC_BKPT32: 128 case ESR_ELx_EC_BRK64: 129 break; 130 default: 131 kvm_err("%s: un-handled case hsr: %#08x\n", 132 __func__, (unsigned int) hsr); 133 ret = -1; 134 break; 135 } 136 137 return ret; 138 } 139 140 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) 141 { 142 u32 hsr = kvm_vcpu_get_hsr(vcpu); 143 144 kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n", 145 hsr, esr_get_class_string(hsr)); 146 147 kvm_inject_undefined(vcpu); 148 return 1; 149 } 150 151 static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) 152 { 153 /* Until SVE is supported for guests: */ 154 kvm_inject_undefined(vcpu); 155 return 1; 156 } 157 158 static exit_handle_fn arm_exit_handlers[] = { 159 [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, 160 [ESR_ELx_EC_WFx] = kvm_handle_wfx, 161 [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, 162 [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, 163 [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32, 164 [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store, 165 [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64, 166 [ESR_ELx_EC_HVC32] = handle_hvc, 167 [ESR_ELx_EC_SMC32] = handle_smc, 168 [ESR_ELx_EC_HVC64] = handle_hvc, 169 [ESR_ELx_EC_SMC64] = handle_smc, 170 [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, 171 [ESR_ELx_EC_SVE] = handle_sve, 172 [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, 173 [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, 174 [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, 175 [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug, 176 [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, 177 [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, 178 [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, 179 [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd, 180 }; 181 182 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) 183 { 184 u32 hsr = kvm_vcpu_get_hsr(vcpu); 185 u8 hsr_ec = ESR_ELx_EC(hsr); 186 187 return arm_exit_handlers[hsr_ec]; 188 } 189 190 /* 191 * We may be single-stepping an emulated instruction. If the emulation 192 * has been completed in the kernel, we can return to userspace with a 193 * KVM_EXIT_DEBUG, otherwise userspace needs to complete its 194 * emulation first. 195 */ 196 static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) 197 { 198 int handled; 199 200 /* 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 handled = 1; 207 } else { 208 exit_handle_fn exit_handler; 209 210 exit_handler = kvm_get_exit_handler(vcpu); 211 handled = exit_handler(vcpu, run); 212 } 213 214 /* 215 * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run 216 * structure if we need to return to userspace. 217 */ 218 if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run)) 219 handled = 0; 220 221 return handled; 222 } 223 224 /* 225 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on 226 * proper exit to userspace. 227 */ 228 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, 229 int exception_index) 230 { 231 if (ARM_SERROR_PENDING(exception_index)) { 232 u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); 233 234 /* 235 * HVC/SMC already have an adjusted PC, which we need 236 * to correct in order to return to after having 237 * injected the SError. 238 */ 239 if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 || 240 hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) { 241 u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2; 242 *vcpu_pc(vcpu) -= adj; 243 } 244 245 kvm_inject_vabt(vcpu); 246 return 1; 247 } 248 249 exception_index = ARM_EXCEPTION_CODE(exception_index); 250 251 switch (exception_index) { 252 case ARM_EXCEPTION_IRQ: 253 return 1; 254 case ARM_EXCEPTION_EL1_SERROR: 255 kvm_inject_vabt(vcpu); 256 /* We may still need to return for single-step */ 257 if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS) 258 && kvm_arm_handle_step_debug(vcpu, run)) 259 return 0; 260 else 261 return 1; 262 case ARM_EXCEPTION_TRAP: 263 return handle_trap_exceptions(vcpu, run); 264 case ARM_EXCEPTION_HYP_GONE: 265 /* 266 * EL2 has been reset to the hyp-stub. This happens when a guest 267 * is pre-empted by kvm_reboot()'s shutdown call. 268 */ 269 run->exit_reason = KVM_EXIT_FAIL_ENTRY; 270 return 0; 271 default: 272 kvm_pr_unimpl("Unsupported exception type: %d", 273 exception_index); 274 run->exit_reason = KVM_EXIT_INTERNAL_ERROR; 275 return 0; 276 } 277 } 278