arch/arm64/kvm/inject_fault.c

   1 /*
   2  * Fault injection for both 32 and 64bit guests.
   3  *
   4  * Copyright (C) 2012,2013 - ARM Ltd
   5  * Author: Marc Zyngier <marc.zyngier@arm.com>
   6  *
   7  * Based on arch/arm/kvm/emulate.c
   8  * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   9  * Author: Christoffer Dall <c.dall@virtualopensystems.com>
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #include <linux/kvm_host.h>
  25 #include <asm/kvm_emulate.h>
  26 #include <asm/esr.h>
  27
  28 #define PSTATE_FAULT_BITS_64    (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \
  29                                  PSR_I_BIT | PSR_D_BIT)
  30 #define EL1_EXCEPT_SYNC_OFFSET  0x200
  31
  32 static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
  33 {
  34         unsigned long cpsr;
  35         unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
  36         bool is_thumb = (new_spsr_value & COMPAT_PSR_T_BIT);
  37         u32 return_offset = (is_thumb) ? 4 : 0;
  38         u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
  39
  40         cpsr = mode | COMPAT_PSR_I_BIT;
  41
  42         if (sctlr & (1 << 30))
  43                 cpsr |= COMPAT_PSR_T_BIT;
  44         if (sctlr & (1 << 25))
  45                 cpsr |= COMPAT_PSR_E_BIT;
  46
  47         *vcpu_cpsr(vcpu) = cpsr;
  48
  49         /* Note: These now point to the banked copies */
  50         *vcpu_spsr(vcpu) = new_spsr_value;
  51         *vcpu_reg(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
  52
  53         /* Branch to exception vector */
  54         if (sctlr & (1 << 13))
  55                 vect_offset += 0xffff0000;
  56         else /* always have security exceptions */
  57                 vect_offset += vcpu_cp15(vcpu, c12_VBAR);
  58
  59         *vcpu_pc(vcpu) = vect_offset;
  60 }
  61
  62 static void inject_undef32(struct kvm_vcpu *vcpu)
  63 {
  64         prepare_fault32(vcpu, COMPAT_PSR_MODE_UND, 4);
  65 }
  66
  67 /*
  68  * Modelled after TakeDataAbortException() and TakePrefetchAbortException
  69  * pseudocode.
  70  */
  71 static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
  72                          unsigned long addr)
  73 {
  74         u32 vect_offset;
  75         u32 *far, *fsr;
  76         bool is_lpae;
  77
  78         if (is_pabt) {
  79                 vect_offset = 12;
  80                 far = &vcpu_cp15(vcpu, c6_IFAR);
  81                 fsr = &vcpu_cp15(vcpu, c5_IFSR);
  82         } else { /* !iabt */
  83                 vect_offset = 16;
  84                 far = &vcpu_cp15(vcpu, c6_DFAR);
  85                 fsr = &vcpu_cp15(vcpu, c5_DFSR);
  86         }
  87
  88         prepare_fault32(vcpu, COMPAT_PSR_MODE_ABT | COMPAT_PSR_A_BIT, vect_offset);
  89
  90         *far = addr;
  91
  92         /* Give the guest an IMPLEMENTATION DEFINED exception */
  93         is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
  94         if (is_lpae)
  95                 *fsr = 1 << 9 | 0x34;
  96         else
  97                 *fsr = 0x14;
  98 }
  99
 100 static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
 101 {
 102         unsigned long cpsr = *vcpu_cpsr(vcpu);
 103         bool is_aarch32;
 104         u32 esr = 0;
 105
 106         is_aarch32 = vcpu_mode_is_32bit(vcpu);
 107
 108         *vcpu_spsr(vcpu) = cpsr;
 109         *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
 110
 111         *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
 112         *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET;
 113
 114         vcpu_sys_reg(vcpu, FAR_EL1) = addr;
 115
 116         /*
 117          * Build an {i,d}abort, depending on the level and the
 118          * instruction set. Report an external synchronous abort.
 119          */
 120         if (kvm_vcpu_trap_il_is32bit(vcpu))
 121                 esr |= ESR_ELx_IL;
 122
 123         /*
 124          * Here, the guest runs in AArch64 mode when in EL1. If we get
 125          * an AArch32 fault, it means we managed to trap an EL0 fault.
 126          */
 127         if (is_aarch32 || (cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t)
 128                 esr |= (ESR_ELx_EC_IABT_LOW << ESR_ELx_EC_SHIFT);
 129         else
 130                 esr |= (ESR_ELx_EC_IABT_CUR << ESR_ELx_EC_SHIFT);
 131
 132         if (!is_iabt)
 133                 esr |= ESR_ELx_EC_DABT_LOW;
 134
 135         vcpu_sys_reg(vcpu, ESR_EL1) = esr | ESR_ELx_FSC_EXTABT;
 136 }
 137
 138 static void inject_undef64(struct kvm_vcpu *vcpu)
 139 {
 140         unsigned long cpsr = *vcpu_cpsr(vcpu);
 141         u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
 142
 143         *vcpu_spsr(vcpu) = cpsr;
 144         *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
 145
 146         *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
 147         *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET;
 148
 149         /*
 150          * Build an unknown exception, depending on the instruction
 151          * set.
 152          */
 153         if (kvm_vcpu_trap_il_is32bit(vcpu))
 154                 esr |= ESR_ELx_IL;
 155
 156         vcpu_sys_reg(vcpu, ESR_EL1) = esr;
 157 }
 158
 159 /**
 160  * kvm_inject_dabt - inject a data abort into the guest
 161  * @vcpu: The VCPU to receive the undefined exception
 162  * @addr: The address to report in the DFAR
 163  *
 164  * It is assumed that this code is called from the VCPU thread and that the
 165  * VCPU therefore is not currently executing guest code.
 166  */
 167 void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
 168 {
 169         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 170                 inject_abt32(vcpu, false, addr);
 171         else
 172                 inject_abt64(vcpu, false, addr);
 173 }
 174
 175 /**
 176  * kvm_inject_pabt - inject a prefetch abort into the guest
 177  * @vcpu: The VCPU to receive the undefined exception
 178  * @addr: The address to report in the DFAR
 179  *
 180  * It is assumed that this code is called from the VCPU thread and that the
 181  * VCPU therefore is not currently executing guest code.
 182  */
 183 void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
 184 {
 185         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 186                 inject_abt32(vcpu, true, addr);
 187         else
 188                 inject_abt64(vcpu, true, addr);
 189 }
 190
 191 /**
 192  * kvm_inject_undefined - inject an undefined instruction into the guest
 193  *
 194  * It is assumed that this code is called from the VCPU thread and that the
 195  * VCPU therefore is not currently executing guest code.
 196  */
 197 void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 198 {
 199         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 200                 inject_undef32(vcpu);
 201         else
 202                 inject_undef64(vcpu);
 203 }