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 <kvm/arm_psci.h> 26 27 #include <asm/esr.h> 28 #include <asm/exception.h> 29 #include <asm/kvm_asm.h> 30 #include <asm/kvm_coproc.h> 31 #include <asm/kvm_emulate.h> 32 #include <asm/kvm_mmu.h> 33 #include <asm/debug-monitors.h> 34 #include <asm/traps.h> 35 36 #define CREATE_TRACE_POINTS 37 #include "trace.h" 38 39 typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *); 40 41 static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr) 42 { 43 if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(NULL, esr)) 44 kvm_inject_vabt(vcpu); 45 } 46 47 static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) 48 { 49 int ret; 50 51 trace_kvm_hvc_arm64(*vcpu_pc(vcpu), vcpu_get_reg(vcpu, 0), 52 kvm_vcpu_hvc_get_imm(vcpu)); 53 vcpu->stat.hvc_exit_stat++; 54 55 ret = kvm_hvc_call_handler(vcpu); 56 if (ret < 0) { 57 vcpu_set_reg(vcpu, 0, ~0UL); 58 return 1; 59 } 60 61 return ret; 62 } 63 64 static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) 65 { 66 /* 67 * "If an SMC instruction executed at Non-secure EL1 is 68 * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a 69 * Trap exception, not a Secure Monitor Call exception [...]" 70 * 71 * We need to advance the PC after the trap, as it would 72 * otherwise return to the same address... 73 */ 74 vcpu_set_reg(vcpu, 0, ~0UL); 75 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 76 return 1; 77 } 78 79 /* 80 * Guest access to FP/ASIMD registers are routed to this handler only 81 * when the system doesn't support FP/ASIMD. 82 */ 83 static int handle_no_fpsimd(struct kvm_vcpu *vcpu, struct kvm_run *run) 84 { 85 kvm_inject_undefined(vcpu); 86 return 1; 87 } 88 89 /** 90 * kvm_handle_wfx - handle a wait-for-interrupts or wait-for-event 91 * instruction executed by a guest 92 * 93 * @vcpu: the vcpu pointer 94 * 95 * WFE: Yield the CPU and come back to this vcpu when the scheduler 96 * decides to. 97 * WFI: Simply call kvm_vcpu_block(), which will halt execution of 98 * world-switches and schedule other host processes until there is an 99 * incoming IRQ or FIQ to the VM. 100 */ 101 static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) 102 { 103 if (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_WFx_ISS_WFE) { 104 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), true); 105 vcpu->stat.wfe_exit_stat++; 106 kvm_vcpu_on_spin(vcpu, vcpu_mode_priv(vcpu)); 107 } else { 108 trace_kvm_wfx_arm64(*vcpu_pc(vcpu), false); 109 vcpu->stat.wfi_exit_stat++; 110 kvm_vcpu_block(vcpu); 111 kvm_clear_request(KVM_REQ_UNHALT, vcpu); 112 } 113 114 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 115 116 return 1; 117 } 118 119 /** 120 * kvm_handle_guest_debug - handle a debug exception instruction 121 * 122 * @vcpu: the vcpu pointer 123 * @run: access to the kvm_run structure for results 124 * 125 * We route all debug exceptions through the same handler. If both the 126 * guest and host are using the same debug facilities it will be up to 127 * userspace to re-inject the correct exception for guest delivery. 128 * 129 * @return: 0 (while setting run->exit_reason), -1 for error 130 */ 131 static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) 132 { 133 u32 hsr = kvm_vcpu_get_hsr(vcpu); 134 int ret = 0; 135 136 run->exit_reason = KVM_EXIT_DEBUG; 137 run->debug.arch.hsr = hsr; 138 139 switch (ESR_ELx_EC(hsr)) { 140 case ESR_ELx_EC_WATCHPT_LOW: 141 run->debug.arch.far = vcpu->arch.fault.far_el2; 142 /* fall through */ 143 case ESR_ELx_EC_SOFTSTP_LOW: 144 case ESR_ELx_EC_BREAKPT_LOW: 145 case ESR_ELx_EC_BKPT32: 146 case ESR_ELx_EC_BRK64: 147 break; 148 default: 149 kvm_err("%s: un-handled case hsr: %#08x\n", 150 __func__, (unsigned int) hsr); 151 ret = -1; 152 break; 153 } 154 155 return ret; 156 } 157 158 static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) 159 { 160 u32 hsr = kvm_vcpu_get_hsr(vcpu); 161 162 kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n", 163 hsr, esr_get_class_string(hsr)); 164 165 kvm_inject_undefined(vcpu); 166 return 1; 167 } 168 169 static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) 170 { 171 /* Until SVE is supported for guests: */ 172 kvm_inject_undefined(vcpu); 173 return 1; 174 } 175 176 static exit_handle_fn arm_exit_handlers[] = { 177 [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, 178 [ESR_ELx_EC_WFx] = kvm_handle_wfx, 179 [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, 180 [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, 181 [ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32, 182 [ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store, 183 [ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64, 184 [ESR_ELx_EC_HVC32] = handle_hvc, 185 [ESR_ELx_EC_SMC32] = handle_smc, 186 [ESR_ELx_EC_HVC64] = handle_hvc, 187 [ESR_ELx_EC_SMC64] = handle_smc, 188 [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, 189 [ESR_ELx_EC_SVE] = handle_sve, 190 [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, 191 [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, 192 [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, 193 [ESR_ELx_EC_WATCHPT_LOW]= kvm_handle_guest_debug, 194 [ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug, 195 [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, 196 [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, 197 [ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd, 198 }; 199 200 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) 201 { 202 u32 hsr = kvm_vcpu_get_hsr(vcpu); 203 u8 hsr_ec = ESR_ELx_EC(hsr); 204 205 return arm_exit_handlers[hsr_ec]; 206 } 207 208 /* 209 * We may be single-stepping an emulated instruction. If the emulation 210 * has been completed in the kernel, we can return to userspace with a 211 * KVM_EXIT_DEBUG, otherwise userspace needs to complete its 212 * emulation first. 213 */ 214 static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) 215 { 216 int handled; 217 218 /* 219 * See ARM ARM B1.14.1: "Hyp traps on instructions 220 * that fail their condition code check" 221 */ 222 if (!kvm_condition_valid(vcpu)) { 223 kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); 224 handled = 1; 225 } else { 226 exit_handle_fn exit_handler; 227 228 exit_handler = kvm_get_exit_handler(vcpu); 229 handled = exit_handler(vcpu, run); 230 } 231 232 /* 233 * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run 234 * structure if we need to return to userspace. 235 */ 236 if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run)) 237 handled = 0; 238 239 return handled; 240 } 241 242 /* 243 * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on 244 * proper exit to userspace. 245 */ 246 int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, 247 int exception_index) 248 { 249 if (ARM_SERROR_PENDING(exception_index)) { 250 u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); 251 252 /* 253 * HVC/SMC already have an adjusted PC, which we need 254 * to correct in order to return to after having 255 * injected the SError. 256 */ 257 if (hsr_ec == ESR_ELx_EC_HVC32 || hsr_ec == ESR_ELx_EC_HVC64 || 258 hsr_ec == ESR_ELx_EC_SMC32 || hsr_ec == ESR_ELx_EC_SMC64) { 259 u32 adj = kvm_vcpu_trap_il_is32bit(vcpu) ? 4 : 2; 260 *vcpu_pc(vcpu) -= adj; 261 } 262 263 return 1; 264 } 265 266 exception_index = ARM_EXCEPTION_CODE(exception_index); 267 268 switch (exception_index) { 269 case ARM_EXCEPTION_IRQ: 270 return 1; 271 case ARM_EXCEPTION_EL1_SERROR: 272 /* We may still need to return for single-step */ 273 if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS) 274 && kvm_arm_handle_step_debug(vcpu, run)) 275 return 0; 276 else 277 return 1; 278 case ARM_EXCEPTION_TRAP: 279 return handle_trap_exceptions(vcpu, run); 280 case ARM_EXCEPTION_HYP_GONE: 281 /* 282 * EL2 has been reset to the hyp-stub. This happens when a guest 283 * is pre-empted by kvm_reboot()'s shutdown call. 284 */ 285 run->exit_reason = KVM_EXIT_FAIL_ENTRY; 286 return 0; 287 default: 288 kvm_pr_unimpl("Unsupported exception type: %d", 289 exception_index); 290 run->exit_reason = KVM_EXIT_INTERNAL_ERROR; 291 return 0; 292 } 293 } 294 295 /* For exit types that need handling before we can be preempted */ 296 void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run, 297 int exception_index) 298 { 299 if (ARM_SERROR_PENDING(exception_index)) { 300 if (this_cpu_has_cap(ARM64_HAS_RAS_EXTN)) { 301 u64 disr = kvm_vcpu_get_disr(vcpu); 302 303 kvm_handle_guest_serror(vcpu, disr_to_esr(disr)); 304 } else { 305 kvm_inject_vabt(vcpu); 306 } 307 308 return; 309 } 310 311 exception_index = ARM_EXCEPTION_CODE(exception_index); 312 313 if (exception_index == ARM_EXCEPTION_EL1_SERROR) 314 kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu)); 315 } 316