1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (C) 2020 - Google Inc 4 * Author: Andrew Scull <ascull@google.com> 5 */ 6 7#include <linux/linkage.h> 8 9#include <asm/assembler.h> 10#include <asm/kvm_arm.h> 11#include <asm/kvm_asm.h> 12#include <asm/kvm_mmu.h> 13#include <asm/kvm_ptrauth.h> 14 15 .text 16 17SYM_FUNC_START(__host_exit) 18 get_host_ctxt x0, x1 19 20 /* Store the host regs x2 and x3 */ 21 stp x2, x3, [x0, #CPU_XREG_OFFSET(2)] 22 23 /* Retrieve the host regs x0-x1 from the stack */ 24 ldp x2, x3, [sp], #16 // x0, x1 25 26 /* Store the host regs x0-x1 and x4-x17 */ 27 stp x2, x3, [x0, #CPU_XREG_OFFSET(0)] 28 stp x4, x5, [x0, #CPU_XREG_OFFSET(4)] 29 stp x6, x7, [x0, #CPU_XREG_OFFSET(6)] 30 stp x8, x9, [x0, #CPU_XREG_OFFSET(8)] 31 stp x10, x11, [x0, #CPU_XREG_OFFSET(10)] 32 stp x12, x13, [x0, #CPU_XREG_OFFSET(12)] 33 stp x14, x15, [x0, #CPU_XREG_OFFSET(14)] 34 stp x16, x17, [x0, #CPU_XREG_OFFSET(16)] 35 36 /* Store the host regs x18-x29, lr */ 37 save_callee_saved_regs x0 38 39 /* Save the host context pointer in x29 across the function call */ 40 mov x29, x0 41 42#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL 43alternative_if_not ARM64_HAS_ADDRESS_AUTH 44b __skip_pauth_save 45alternative_else_nop_endif 46 47alternative_if ARM64_KVM_PROTECTED_MODE 48 /* Save kernel ptrauth keys. */ 49 add x18, x29, #CPU_APIAKEYLO_EL1 50 ptrauth_save_state x18, x19, x20 51 52 /* Use hyp keys. */ 53 adr_this_cpu x18, kvm_hyp_ctxt, x19 54 add x18, x18, #CPU_APIAKEYLO_EL1 55 ptrauth_restore_state x18, x19, x20 56 isb 57alternative_else_nop_endif 58__skip_pauth_save: 59#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ 60 61 bl handle_trap 62 63__host_enter_restore_full: 64 /* Restore kernel keys. */ 65#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL 66alternative_if_not ARM64_HAS_ADDRESS_AUTH 67b __skip_pauth_restore 68alternative_else_nop_endif 69 70alternative_if ARM64_KVM_PROTECTED_MODE 71 add x18, x29, #CPU_APIAKEYLO_EL1 72 ptrauth_restore_state x18, x19, x20 73alternative_else_nop_endif 74__skip_pauth_restore: 75#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */ 76 77 /* Restore host regs x0-x17 */ 78 ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)] 79 ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)] 80 ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)] 81 ldp x6, x7, [x29, #CPU_XREG_OFFSET(6)] 82 83 /* x0-7 are use for panic arguments */ 84__host_enter_for_panic: 85 ldp x8, x9, [x29, #CPU_XREG_OFFSET(8)] 86 ldp x10, x11, [x29, #CPU_XREG_OFFSET(10)] 87 ldp x12, x13, [x29, #CPU_XREG_OFFSET(12)] 88 ldp x14, x15, [x29, #CPU_XREG_OFFSET(14)] 89 ldp x16, x17, [x29, #CPU_XREG_OFFSET(16)] 90 91 /* Restore host regs x18-x29, lr */ 92 restore_callee_saved_regs x29 93 94 /* Do not touch any register after this! */ 95__host_enter_without_restoring: 96 eret 97 sb 98SYM_FUNC_END(__host_exit) 99 100/* 101 * void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt); 102 */ 103SYM_FUNC_START(__host_enter) 104 mov x29, x0 105 b __host_enter_restore_full 106SYM_FUNC_END(__host_enter) 107 108/* 109 * void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr, 110 * u64 elr, u64 par); 111 */ 112SYM_FUNC_START(__hyp_do_panic) 113 /* Prepare and exit to the host's panic function. */ 114 mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\ 115 PSR_MODE_EL1h) 116 msr spsr_el2, lr 117 adr_l lr, nvhe_hyp_panic_handler 118 hyp_kimg_va lr, x6 119 msr elr_el2, lr 120 121 mov x29, x0 122 123#ifdef PKVM_DISABLE_STAGE2_ON_PANIC 124 /* Ensure host stage-2 is disabled */ 125 mrs x0, hcr_el2 126 bic x0, x0, #HCR_VM 127 msr_hcr_el2 x0 128 tlbi vmalls12e1 129 dsb nsh 130#endif 131 132 /* Load the panic arguments into x0-7 */ 133 mrs x0, esr_el2 134 mov x4, x3 135 mov x3, x2 136 hyp_pa x3, x6 137 get_vcpu_ptr x5, x6 138 mrs x6, far_el2 139 mrs x7, hpfar_el2 140 141 /* Enter the host, conditionally restoring the host context. */ 142 cbz x29, __host_enter_without_restoring 143 b __host_enter_for_panic 144SYM_FUNC_END(__hyp_do_panic) 145 146SYM_FUNC_START(__host_hvc) 147 ldp x0, x1, [sp] // Don't fixup the stack yet 148 149 /* No stub for you, sonny Jim */ 150alternative_if ARM64_KVM_PROTECTED_MODE 151 b __host_exit 152alternative_else_nop_endif 153 154 /* Check for a stub HVC call */ 155 cmp x0, #HVC_STUB_HCALL_NR 156 b.hs __host_exit 157 158 add sp, sp, #16 159 /* 160 * Compute the idmap address of __kvm_handle_stub_hvc and 161 * jump there. 162 * 163 * Preserve x0-x4, which may contain stub parameters. 164 */ 165 adr_l x5, __kvm_handle_stub_hvc 166 hyp_pa x5, x6 167 br x5 168SYM_FUNC_END(__host_hvc) 169 170.macro host_el1_sync_vect 171 .align 7 172.L__vect_start\@: 173 stp x0, x1, [sp, #-16]! 174 mrs x0, esr_el2 175 ubfx x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH 176 cmp x0, #ESR_ELx_EC_HVC64 177 b.eq __host_hvc 178 b __host_exit 179.L__vect_end\@: 180.if ((.L__vect_end\@ - .L__vect_start\@) > 0x80) 181 .error "host_el1_sync_vect larger than vector entry" 182.endif 183.endm 184 185.macro invalid_host_el2_vect 186 .align 7 187 188 /* 189 * Test whether the SP has overflowed, without corrupting a GPR. 190 * nVHE hypervisor stacks are aligned so that the NVHE_STACK_SHIFT bit 191 * of SP should always be 1. 192 */ 193 add sp, sp, x0 // sp' = sp + x0 194 sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp 195 tbz x0, #NVHE_STACK_SHIFT, .L__hyp_sp_overflow\@ 196 sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0 197 sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp 198 199 /* 200 * The panic may not be clean if the exception is taken before the host 201 * context has been saved by __host_exit or after the hyp context has 202 * been partially clobbered by __host_enter. 203 */ 204 b hyp_panic 205 206.L__hyp_sp_overflow\@: 207 /* Switch to the overflow stack */ 208 adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0 209 210 b hyp_panic_bad_stack 211 ASM_BUG() 212.endm 213 214.macro invalid_host_el1_vect 215 .align 7 216 mov x0, xzr /* restore_host = false */ 217 mrs x1, spsr_el2 218 mrs x2, elr_el2 219 mrs x3, par_el1 220 b __hyp_do_panic 221.endm 222 223/* 224 * The host vector does not use an ESB instruction in order to avoid consuming 225 * SErrors that should only be consumed by the host. Guest entry is deferred by 226 * __guest_enter if there are any pending asynchronous exceptions so hyp will 227 * always return to the host without having consumerd host SErrors. 228 * 229 * CONFIG_KVM_INDIRECT_VECTORS is not applied to the host vectors because the 230 * host knows about the EL2 vectors already, and there is no point in hiding 231 * them. 232 */ 233 .align 11 234SYM_CODE_START(__kvm_hyp_host_vector) 235 invalid_host_el2_vect // Synchronous EL2t 236 invalid_host_el2_vect // IRQ EL2t 237 invalid_host_el2_vect // FIQ EL2t 238 invalid_host_el2_vect // Error EL2t 239 240 invalid_host_el2_vect // Synchronous EL2h 241 invalid_host_el2_vect // IRQ EL2h 242 invalid_host_el2_vect // FIQ EL2h 243 invalid_host_el2_vect // Error EL2h 244 245 host_el1_sync_vect // Synchronous 64-bit EL1/EL0 246 invalid_host_el1_vect // IRQ 64-bit EL1/EL0 247 invalid_host_el1_vect // FIQ 64-bit EL1/EL0 248 invalid_host_el1_vect // Error 64-bit EL1/EL0 249 250 host_el1_sync_vect // Synchronous 32-bit EL1/EL0 251 invalid_host_el1_vect // IRQ 32-bit EL1/EL0 252 invalid_host_el1_vect // FIQ 32-bit EL1/EL0 253 invalid_host_el1_vect // Error 32-bit EL1/EL0 254SYM_CODE_END(__kvm_hyp_host_vector) 255 256/* 257 * Forward SMC with arguments in struct kvm_cpu_context, and 258 * store the result into the same struct. Assumes SMCCC 1.2 or older. 259 * 260 * x0: struct kvm_cpu_context* 261 */ 262SYM_CODE_START(__kvm_hyp_host_forward_smc) 263 /* 264 * Use x18 to keep the pointer to the host context because 265 * x18 is callee-saved in SMCCC but not in AAPCS64. 266 */ 267 mov x18, x0 268 269 ldp x0, x1, [x18, #CPU_XREG_OFFSET(0)] 270 ldp x2, x3, [x18, #CPU_XREG_OFFSET(2)] 271 ldp x4, x5, [x18, #CPU_XREG_OFFSET(4)] 272 ldp x6, x7, [x18, #CPU_XREG_OFFSET(6)] 273 ldp x8, x9, [x18, #CPU_XREG_OFFSET(8)] 274 ldp x10, x11, [x18, #CPU_XREG_OFFSET(10)] 275 ldp x12, x13, [x18, #CPU_XREG_OFFSET(12)] 276 ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)] 277 ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)] 278 279 smc #0 280 281 stp x0, x1, [x18, #CPU_XREG_OFFSET(0)] 282 stp x2, x3, [x18, #CPU_XREG_OFFSET(2)] 283 stp x4, x5, [x18, #CPU_XREG_OFFSET(4)] 284 stp x6, x7, [x18, #CPU_XREG_OFFSET(6)] 285 stp x8, x9, [x18, #CPU_XREG_OFFSET(8)] 286 stp x10, x11, [x18, #CPU_XREG_OFFSET(10)] 287 stp x12, x13, [x18, #CPU_XREG_OFFSET(12)] 288 stp x14, x15, [x18, #CPU_XREG_OFFSET(14)] 289 stp x16, x17, [x18, #CPU_XREG_OFFSET(16)] 290 291 ret 292SYM_CODE_END(__kvm_hyp_host_forward_smc) 293