1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (C) 2015 - ARM Ltd 4 * Author: Marc Zyngier <marc.zyngier@arm.com> 5 */ 6 7#include <linux/linkage.h> 8 9#include <asm/alternative.h> 10#include <asm/assembler.h> 11#include <asm/fpsimdmacros.h> 12#include <asm/kvm.h> 13#include <asm/kvm_arm.h> 14#include <asm/kvm_asm.h> 15#include <asm/kvm_mmu.h> 16#include <asm/kvm_ptrauth.h> 17 18 .text 19 20/* 21 * u64 __guest_enter(struct kvm_vcpu *vcpu); 22 */ 23SYM_FUNC_START(__guest_enter) 24 // x0: vcpu 25 // x1-x17: clobbered by macros 26 // x29: guest context 27 28 adr_this_cpu x1, kvm_hyp_ctxt, x2 29 30 // Store the hyp regs 31 save_callee_saved_regs x1 32 33 // Save hyp's sp_el0 34 save_sp_el0 x1, x2 35 36 // Now the hyp state is stored if we have a pending RAS SError it must 37 // affect the host or hyp. If any asynchronous exception is pending we 38 // defer the guest entry. The DSB isn't necessary before v8.2 as any 39 // SError would be fatal. 40alternative_if ARM64_HAS_RAS_EXTN 41 dsb nshst 42 isb 43alternative_else_nop_endif 44 mrs x1, isr_el1 45 cbz x1, 1f 46 mov x0, #ARM_EXCEPTION_IRQ 47 ret 48 491: 50 set_loaded_vcpu x0, x1, x2 51 52 add x29, x0, #VCPU_CONTEXT 53 54 // Macro ptrauth_switch_to_guest format: 55 // ptrauth_switch_to_guest(guest cxt, tmp1, tmp2, tmp3) 56 // The below macro to restore guest keys is not implemented in C code 57 // as it may cause Pointer Authentication key signing mismatch errors 58 // when this feature is enabled for kernel code. 59 ptrauth_switch_to_guest x29, x0, x1, x2 60 61 // Restore the guest's sp_el0 62 restore_sp_el0 x29, x0 63 64 // Restore guest regs x0-x17 65 ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)] 66 ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)] 67 ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)] 68 ldp x6, x7, [x29, #CPU_XREG_OFFSET(6)] 69 ldp x8, x9, [x29, #CPU_XREG_OFFSET(8)] 70 ldp x10, x11, [x29, #CPU_XREG_OFFSET(10)] 71 ldp x12, x13, [x29, #CPU_XREG_OFFSET(12)] 72 ldp x14, x15, [x29, #CPU_XREG_OFFSET(14)] 73 ldp x16, x17, [x29, #CPU_XREG_OFFSET(16)] 74 75 // Restore guest regs x18-x29, lr 76 restore_callee_saved_regs x29 77 78 // Do not touch any register after this! 79 eret 80 sb 81 82SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) 83 // x2-x29,lr: vcpu regs 84 // vcpu x0-x1 on the stack 85 86 // If the hyp context is loaded, go straight to hyp_panic 87 get_loaded_vcpu x0, x1 88 cbnz x0, 1f 89 b hyp_panic 90 911: 92 // The hyp context is saved so make sure it is restored to allow 93 // hyp_panic to run at hyp and, subsequently, panic to run in the host. 94 // This makes use of __guest_exit to avoid duplication but sets the 95 // return address to tail call into hyp_panic. As a side effect, the 96 // current state is saved to the guest context but it will only be 97 // accurate if the guest had been completely restored. 98 adr_this_cpu x0, kvm_hyp_ctxt, x1 99 adr_l x1, hyp_panic 100 str x1, [x0, #CPU_XREG_OFFSET(30)] 101 102 get_vcpu_ptr x1, x0 103 104SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) 105 // x0: return code 106 // x1: vcpu 107 // x2-x29,lr: vcpu regs 108 // vcpu x0-x1 on the stack 109 110 add x1, x1, #VCPU_CONTEXT 111 112 ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN) 113 114 // Store the guest regs x2 and x3 115 stp x2, x3, [x1, #CPU_XREG_OFFSET(2)] 116 117 // Retrieve the guest regs x0-x1 from the stack 118 ldp x2, x3, [sp], #16 // x0, x1 119 120 // Store the guest regs x0-x1 and x4-x17 121 stp x2, x3, [x1, #CPU_XREG_OFFSET(0)] 122 stp x4, x5, [x1, #CPU_XREG_OFFSET(4)] 123 stp x6, x7, [x1, #CPU_XREG_OFFSET(6)] 124 stp x8, x9, [x1, #CPU_XREG_OFFSET(8)] 125 stp x10, x11, [x1, #CPU_XREG_OFFSET(10)] 126 stp x12, x13, [x1, #CPU_XREG_OFFSET(12)] 127 stp x14, x15, [x1, #CPU_XREG_OFFSET(14)] 128 stp x16, x17, [x1, #CPU_XREG_OFFSET(16)] 129 130 // Store the guest regs x18-x29, lr 131 save_callee_saved_regs x1 132 133 // Store the guest's sp_el0 134 save_sp_el0 x1, x2 135 136 adr_this_cpu x2, kvm_hyp_ctxt, x3 137 138 // Macro ptrauth_switch_to_hyp format: 139 // ptrauth_switch_to_hyp(guest cxt, host cxt, tmp1, tmp2, tmp3) 140 // The below macro to save/restore keys is not implemented in C code 141 // as it may cause Pointer Authentication key signing mismatch errors 142 // when this feature is enabled for kernel code. 143 ptrauth_switch_to_hyp x1, x2, x3, x4, x5 144 145 // Restore hyp's sp_el0 146 restore_sp_el0 x2, x3 147 148 // Now restore the hyp regs 149 restore_callee_saved_regs x2 150 151 set_loaded_vcpu xzr, x2, x3 152 153alternative_if ARM64_HAS_RAS_EXTN 154 // If we have the RAS extensions we can consume a pending error 155 // without an unmask-SError and isb. The ESB-instruction consumed any 156 // pending guest error when we took the exception from the guest. 157 mrs_s x2, SYS_DISR_EL1 158 str x2, [x1, #(VCPU_FAULT_DISR - VCPU_CONTEXT)] 159 cbz x2, 1f 160 msr_s SYS_DISR_EL1, xzr 161 orr x0, x0, #(1<<ARM_EXIT_WITH_SERROR_BIT) 1621: ret 163alternative_else 164 dsb sy // Synchronize against in-flight ld/st 165 isb // Prevent an early read of side-effect free ISR 166 mrs x2, isr_el1 167 tbnz x2, #8, 2f // ISR_EL1.A 168 ret 169 nop 1702: 171alternative_endif 172 // We know we have a pending asynchronous abort, now is the 173 // time to flush it out. From your VAXorcist book, page 666: 174 // "Threaten me not, oh Evil one! For I speak with 175 // the power of DEC, and I command thee to show thyself!" 176 mrs x2, elr_el2 177 mrs x3, esr_el2 178 mrs x4, spsr_el2 179 mov x5, x0 180 181 msr daifclr, #4 // Unmask aborts 182 183 // This is our single instruction exception window. A pending 184 // SError is guaranteed to occur at the earliest when we unmask 185 // it, and at the latest just after the ISB. 186abort_guest_exit_start: 187 188 isb 189 190abort_guest_exit_end: 191 192 msr daifset, #4 // Mask aborts 193 ret 194 195 _kvm_extable abort_guest_exit_start, 9997f 196 _kvm_extable abort_guest_exit_end, 9997f 1979997: 198 msr daifset, #4 // Mask aborts 199 mov x0, #(1 << ARM_EXIT_WITH_SERROR_BIT) 200 201 // restore the EL1 exception context so that we can report some 202 // information. Merge the exception code with the SError pending bit. 203 msr elr_el2, x2 204 msr esr_el2, x3 205 msr spsr_el2, x4 206 orr x0, x0, x5 2071: ret 208SYM_FUNC_END(__guest_enter) 209