1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Fault injection for both 32 and 64bit guests. 4 * 5 * Copyright (C) 2012,2013 - ARM Ltd 6 * Author: Marc Zyngier <marc.zyngier@arm.com> 7 * 8 * Based on arch/arm/kvm/emulate.c 9 * Copyright (C) 2012 - Virtual Open Systems and Columbia University 10 * Author: Christoffer Dall <c.dall@virtualopensystems.com> 11 */ 12 13 #include <hyp/adjust_pc.h> 14 #include <linux/kvm_host.h> 15 #include <asm/kvm_emulate.h> 16 #include <asm/kvm_mmu.h> 17 #include <asm/kvm_nested.h> 18 19 #if !defined (__KVM_NVHE_HYPERVISOR__) && !defined (__KVM_VHE_HYPERVISOR__) 20 #error Hypervisor code only! 21 #endif 22 __vcpu_read_sys_reg(const struct kvm_vcpu * vcpu,int reg)23 static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) 24 { 25 u64 val; 26 27 if (unlikely(vcpu_has_nv(vcpu))) 28 return vcpu_read_sys_reg(vcpu, reg); 29 else if (__vcpu_read_sys_reg_from_cpu(reg, &val)) 30 return val; 31 32 return __vcpu_sys_reg(vcpu, reg); 33 } 34 __vcpu_write_sys_reg(struct kvm_vcpu * vcpu,u64 val,int reg)35 static inline void __vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) 36 { 37 if (unlikely(vcpu_has_nv(vcpu))) 38 vcpu_write_sys_reg(vcpu, val, reg); 39 else if (!__vcpu_write_sys_reg_to_cpu(val, reg)) 40 __vcpu_sys_reg(vcpu, reg) = val; 41 } 42 __vcpu_write_spsr(struct kvm_vcpu * vcpu,unsigned long target_mode,u64 val)43 static void __vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long target_mode, 44 u64 val) 45 { 46 if (unlikely(vcpu_has_nv(vcpu))) { 47 if (target_mode == PSR_MODE_EL1h) 48 vcpu_write_sys_reg(vcpu, val, SPSR_EL1); 49 else 50 vcpu_write_sys_reg(vcpu, val, SPSR_EL2); 51 } else if (has_vhe()) { 52 write_sysreg_el1(val, SYS_SPSR); 53 } else { 54 __vcpu_sys_reg(vcpu, SPSR_EL1) = val; 55 } 56 } 57 __vcpu_write_spsr_abt(struct kvm_vcpu * vcpu,u64 val)58 static void __vcpu_write_spsr_abt(struct kvm_vcpu *vcpu, u64 val) 59 { 60 if (has_vhe()) 61 write_sysreg(val, spsr_abt); 62 else 63 vcpu->arch.ctxt.spsr_abt = val; 64 } 65 __vcpu_write_spsr_und(struct kvm_vcpu * vcpu,u64 val)66 static void __vcpu_write_spsr_und(struct kvm_vcpu *vcpu, u64 val) 67 { 68 if (has_vhe()) 69 write_sysreg(val, spsr_und); 70 else 71 vcpu->arch.ctxt.spsr_und = val; 72 } 73 74 /* 75 * This performs the exception entry at a given EL (@target_mode), stashing PC 76 * and PSTATE into ELR and SPSR respectively, and compute the new PC/PSTATE. 77 * The EL passed to this function *must* be a non-secure, privileged mode with 78 * bit 0 being set (PSTATE.SP == 1). 79 * 80 * When an exception is taken, most PSTATE fields are left unchanged in the 81 * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all 82 * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx 83 * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0. 84 * 85 * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429. 86 * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426. 87 * 88 * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from 89 * MSB to LSB. 90 */ enter_exception64(struct kvm_vcpu * vcpu,unsigned long target_mode,enum exception_type type)91 static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, 92 enum exception_type type) 93 { 94 unsigned long sctlr, vbar, old, new, mode; 95 u64 exc_offset; 96 97 mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT); 98 99 if (mode == target_mode) 100 exc_offset = CURRENT_EL_SP_ELx_VECTOR; 101 else if ((mode | PSR_MODE_THREAD_BIT) == target_mode) 102 exc_offset = CURRENT_EL_SP_EL0_VECTOR; 103 else if (!(mode & PSR_MODE32_BIT)) 104 exc_offset = LOWER_EL_AArch64_VECTOR; 105 else 106 exc_offset = LOWER_EL_AArch32_VECTOR; 107 108 switch (target_mode) { 109 case PSR_MODE_EL1h: 110 vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL1); 111 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); 112 __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1); 113 break; 114 case PSR_MODE_EL2h: 115 vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL2); 116 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL2); 117 __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL2); 118 break; 119 default: 120 /* Don't do that */ 121 BUG(); 122 } 123 124 *vcpu_pc(vcpu) = vbar + exc_offset + type; 125 126 old = *vcpu_cpsr(vcpu); 127 new = 0; 128 129 new |= (old & PSR_N_BIT); 130 new |= (old & PSR_Z_BIT); 131 new |= (old & PSR_C_BIT); 132 new |= (old & PSR_V_BIT); 133 134 if (kvm_has_mte(kern_hyp_va(vcpu->kvm))) 135 new |= PSR_TCO_BIT; 136 137 new |= (old & PSR_DIT_BIT); 138 139 // PSTATE.UAO is set to zero upon any exception to AArch64 140 // See ARM DDI 0487E.a, page D5-2579. 141 142 // PSTATE.PAN is unchanged unless SCTLR_ELx.SPAN == 0b0 143 // SCTLR_ELx.SPAN is RES1 when ARMv8.1-PAN is not implemented 144 // See ARM DDI 0487E.a, page D5-2578. 145 new |= (old & PSR_PAN_BIT); 146 if (!(sctlr & SCTLR_EL1_SPAN)) 147 new |= PSR_PAN_BIT; 148 149 // PSTATE.SS is set to zero upon any exception to AArch64 150 // See ARM DDI 0487E.a, page D2-2452. 151 152 // PSTATE.IL is set to zero upon any exception to AArch64 153 // See ARM DDI 0487E.a, page D1-2306. 154 155 // PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64 156 // See ARM DDI 0487E.a, page D13-3258 157 if (sctlr & SCTLR_ELx_DSSBS) 158 new |= PSR_SSBS_BIT; 159 160 // PSTATE.BTYPE is set to zero upon any exception to AArch64 161 // See ARM DDI 0487E.a, pages D1-2293 to D1-2294. 162 163 new |= PSR_D_BIT; 164 new |= PSR_A_BIT; 165 new |= PSR_I_BIT; 166 new |= PSR_F_BIT; 167 168 new |= target_mode; 169 170 *vcpu_cpsr(vcpu) = new; 171 __vcpu_write_spsr(vcpu, target_mode, old); 172 } 173 174 /* 175 * When an exception is taken, most CPSR fields are left unchanged in the 176 * handler. However, some are explicitly overridden (e.g. M[4:0]). 177 * 178 * The SPSR/SPSR_ELx layouts differ, and the below is intended to work with 179 * either format. Note: SPSR.J bit doesn't exist in SPSR_ELx, but this bit was 180 * obsoleted by the ARMv7 virtualization extensions and is RES0. 181 * 182 * For the SPSR layout seen from AArch32, see: 183 * - ARM DDI 0406C.d, page B1-1148 184 * - ARM DDI 0487E.a, page G8-6264 185 * 186 * For the SPSR_ELx layout for AArch32 seen from AArch64, see: 187 * - ARM DDI 0487E.a, page C5-426 188 * 189 * Here we manipulate the fields in order of the AArch32 SPSR_ELx layout, from 190 * MSB to LSB. 191 */ get_except32_cpsr(struct kvm_vcpu * vcpu,u32 mode)192 static unsigned long get_except32_cpsr(struct kvm_vcpu *vcpu, u32 mode) 193 { 194 u32 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); 195 unsigned long old, new; 196 197 old = *vcpu_cpsr(vcpu); 198 new = 0; 199 200 new |= (old & PSR_AA32_N_BIT); 201 new |= (old & PSR_AA32_Z_BIT); 202 new |= (old & PSR_AA32_C_BIT); 203 new |= (old & PSR_AA32_V_BIT); 204 new |= (old & PSR_AA32_Q_BIT); 205 206 // CPSR.IT[7:0] are set to zero upon any exception 207 // See ARM DDI 0487E.a, section G1.12.3 208 // See ARM DDI 0406C.d, section B1.8.3 209 210 new |= (old & PSR_AA32_DIT_BIT); 211 212 // CPSR.SSBS is set to SCTLR.DSSBS upon any exception 213 // See ARM DDI 0487E.a, page G8-6244 214 if (sctlr & BIT(31)) 215 new |= PSR_AA32_SSBS_BIT; 216 217 // CPSR.PAN is unchanged unless SCTLR.SPAN == 0b0 218 // SCTLR.SPAN is RES1 when ARMv8.1-PAN is not implemented 219 // See ARM DDI 0487E.a, page G8-6246 220 new |= (old & PSR_AA32_PAN_BIT); 221 if (!(sctlr & BIT(23))) 222 new |= PSR_AA32_PAN_BIT; 223 224 // SS does not exist in AArch32, so ignore 225 226 // CPSR.IL is set to zero upon any exception 227 // See ARM DDI 0487E.a, page G1-5527 228 229 new |= (old & PSR_AA32_GE_MASK); 230 231 // CPSR.IT[7:0] are set to zero upon any exception 232 // See prior comment above 233 234 // CPSR.E is set to SCTLR.EE upon any exception 235 // See ARM DDI 0487E.a, page G8-6245 236 // See ARM DDI 0406C.d, page B4-1701 237 if (sctlr & BIT(25)) 238 new |= PSR_AA32_E_BIT; 239 240 // CPSR.A is unchanged upon an exception to Undefined, Supervisor 241 // CPSR.A is set upon an exception to other modes 242 // See ARM DDI 0487E.a, pages G1-5515 to G1-5516 243 // See ARM DDI 0406C.d, page B1-1182 244 new |= (old & PSR_AA32_A_BIT); 245 if (mode != PSR_AA32_MODE_UND && mode != PSR_AA32_MODE_SVC) 246 new |= PSR_AA32_A_BIT; 247 248 // CPSR.I is set upon any exception 249 // See ARM DDI 0487E.a, pages G1-5515 to G1-5516 250 // See ARM DDI 0406C.d, page B1-1182 251 new |= PSR_AA32_I_BIT; 252 253 // CPSR.F is set upon an exception to FIQ 254 // CPSR.F is unchanged upon an exception to other modes 255 // See ARM DDI 0487E.a, pages G1-5515 to G1-5516 256 // See ARM DDI 0406C.d, page B1-1182 257 new |= (old & PSR_AA32_F_BIT); 258 if (mode == PSR_AA32_MODE_FIQ) 259 new |= PSR_AA32_F_BIT; 260 261 // CPSR.T is set to SCTLR.TE upon any exception 262 // See ARM DDI 0487E.a, page G8-5514 263 // See ARM DDI 0406C.d, page B1-1181 264 if (sctlr & BIT(30)) 265 new |= PSR_AA32_T_BIT; 266 267 new |= mode; 268 269 return new; 270 } 271 272 /* 273 * Table taken from ARMv8 ARM DDI0487B-B, table G1-10. 274 */ 275 static const u8 return_offsets[8][2] = { 276 [0] = { 0, 0 }, /* Reset, unused */ 277 [1] = { 4, 2 }, /* Undefined */ 278 [2] = { 0, 0 }, /* SVC, unused */ 279 [3] = { 4, 4 }, /* Prefetch abort */ 280 [4] = { 8, 8 }, /* Data abort */ 281 [5] = { 0, 0 }, /* HVC, unused */ 282 [6] = { 4, 4 }, /* IRQ, unused */ 283 [7] = { 4, 4 }, /* FIQ, unused */ 284 }; 285 enter_exception32(struct kvm_vcpu * vcpu,u32 mode,u32 vect_offset)286 static void enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset) 287 { 288 unsigned long spsr = *vcpu_cpsr(vcpu); 289 bool is_thumb = (spsr & PSR_AA32_T_BIT); 290 u32 sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); 291 u32 return_address; 292 293 *vcpu_cpsr(vcpu) = get_except32_cpsr(vcpu, mode); 294 return_address = *vcpu_pc(vcpu); 295 return_address += return_offsets[vect_offset >> 2][is_thumb]; 296 297 /* KVM only enters the ABT and UND modes, so only deal with those */ 298 switch(mode) { 299 case PSR_AA32_MODE_ABT: 300 __vcpu_write_spsr_abt(vcpu, host_spsr_to_spsr32(spsr)); 301 vcpu_gp_regs(vcpu)->compat_lr_abt = return_address; 302 break; 303 304 case PSR_AA32_MODE_UND: 305 __vcpu_write_spsr_und(vcpu, host_spsr_to_spsr32(spsr)); 306 vcpu_gp_regs(vcpu)->compat_lr_und = return_address; 307 break; 308 } 309 310 /* Branch to exception vector */ 311 if (sctlr & (1 << 13)) 312 vect_offset += 0xffff0000; 313 else /* always have security exceptions */ 314 vect_offset += __vcpu_read_sys_reg(vcpu, VBAR_EL1); 315 316 *vcpu_pc(vcpu) = vect_offset; 317 } 318 kvm_inject_exception(struct kvm_vcpu * vcpu)319 static void kvm_inject_exception(struct kvm_vcpu *vcpu) 320 { 321 if (vcpu_el1_is_32bit(vcpu)) { 322 switch (vcpu_get_flag(vcpu, EXCEPT_MASK)) { 323 case unpack_vcpu_flag(EXCEPT_AA32_UND): 324 enter_exception32(vcpu, PSR_AA32_MODE_UND, 4); 325 break; 326 case unpack_vcpu_flag(EXCEPT_AA32_IABT): 327 enter_exception32(vcpu, PSR_AA32_MODE_ABT, 12); 328 break; 329 case unpack_vcpu_flag(EXCEPT_AA32_DABT): 330 enter_exception32(vcpu, PSR_AA32_MODE_ABT, 16); 331 break; 332 default: 333 /* Err... */ 334 break; 335 } 336 } else { 337 switch (vcpu_get_flag(vcpu, EXCEPT_MASK)) { 338 case unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC): 339 enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync); 340 break; 341 342 case unpack_vcpu_flag(EXCEPT_AA64_EL2_SYNC): 343 enter_exception64(vcpu, PSR_MODE_EL2h, except_type_sync); 344 break; 345 346 case unpack_vcpu_flag(EXCEPT_AA64_EL2_IRQ): 347 enter_exception64(vcpu, PSR_MODE_EL2h, except_type_irq); 348 break; 349 350 default: 351 /* 352 * Only EL1_SYNC and EL2_{SYNC,IRQ} makes 353 * sense so far. Everything else gets silently 354 * ignored. 355 */ 356 break; 357 } 358 } 359 } 360 361 /* 362 * Adjust the guest PC (and potentially exception state) depending on 363 * flags provided by the emulation code. 364 */ __kvm_adjust_pc(struct kvm_vcpu * vcpu)365 void __kvm_adjust_pc(struct kvm_vcpu *vcpu) 366 { 367 if (vcpu_get_flag(vcpu, PENDING_EXCEPTION)) { 368 kvm_inject_exception(vcpu); 369 vcpu_clear_flag(vcpu, PENDING_EXCEPTION); 370 vcpu_clear_flag(vcpu, EXCEPT_MASK); 371 } else if (vcpu_get_flag(vcpu, INCREMENT_PC)) { 372 kvm_skip_instr(vcpu); 373 vcpu_clear_flag(vcpu, INCREMENT_PC); 374 } 375 } 376