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
  31 #define CURRENT_EL_SP_EL0_VECTOR        0x0
  32 #define CURRENT_EL_SP_ELx_VECTOR        0x200
  33 #define LOWER_EL_AArch64_VECTOR         0x400
  34 #define LOWER_EL_AArch32_VECTOR         0x600
  35
  36 static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
  37 {
  38         unsigned long cpsr;
  39         unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
  40         bool is_thumb = (new_spsr_value & COMPAT_PSR_T_BIT);
  41         u32 return_offset = (is_thumb) ? 4 : 0;
  42         u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
  43
  44         cpsr = mode | COMPAT_PSR_I_BIT;
  45
  46         if (sctlr & (1 << 30))
  47                 cpsr |= COMPAT_PSR_T_BIT;
  48         if (sctlr & (1 << 25))
  49                 cpsr |= COMPAT_PSR_E_BIT;
  50
  51         *vcpu_cpsr(vcpu) = cpsr;
  52
  53         /* Note: These now point to the banked copies */
  54         *vcpu_spsr(vcpu) = new_spsr_value;
  55         *vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
  56
  57         /* Branch to exception vector */
  58         if (sctlr & (1 << 13))
  59                 vect_offset += 0xffff0000;
  60         else /* always have security exceptions */
  61                 vect_offset += vcpu_cp15(vcpu, c12_VBAR);
  62
  63         *vcpu_pc(vcpu) = vect_offset;
  64 }
  65
  66 static void inject_undef32(struct kvm_vcpu *vcpu)
  67 {
  68         prepare_fault32(vcpu, COMPAT_PSR_MODE_UND, 4);
  69 }
  70
  71 /*
  72  * Modelled after TakeDataAbortException() and TakePrefetchAbortException
  73  * pseudocode.
  74  */
  75 static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
  76                          unsigned long addr)
  77 {
  78         u32 vect_offset;
  79         u32 *far, *fsr;
  80         bool is_lpae;
  81
  82         if (is_pabt) {
  83                 vect_offset = 12;
  84                 far = &vcpu_cp15(vcpu, c6_IFAR);
  85                 fsr = &vcpu_cp15(vcpu, c5_IFSR);
  86         } else { /* !iabt */
  87                 vect_offset = 16;
  88                 far = &vcpu_cp15(vcpu, c6_DFAR);
  89                 fsr = &vcpu_cp15(vcpu, c5_DFSR);
  90         }
  91
  92         prepare_fault32(vcpu, COMPAT_PSR_MODE_ABT | COMPAT_PSR_A_BIT, vect_offset);
  93
  94         *far = addr;
  95
  96         /* Give the guest an IMPLEMENTATION DEFINED exception */
  97         is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
  98         if (is_lpae)
  99                 *fsr = 1 << 9 | 0x34;
 100         else
 101                 *fsr = 0x14;
 102 }
 103
 104 enum exception_type {
 105         except_type_sync        = 0,
 106         except_type_irq         = 0x80,
 107         except_type_fiq         = 0x100,
 108         except_type_serror      = 0x180,
 109 };
 110
 111 static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
 112 {
 113         u64 exc_offset;
 114
 115         switch (*vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT)) {
 116         case PSR_MODE_EL1t:
 117                 exc_offset = CURRENT_EL_SP_EL0_VECTOR;
 118                 break;
 119         case PSR_MODE_EL1h:
 120                 exc_offset = CURRENT_EL_SP_ELx_VECTOR;
 121                 break;
 122         case PSR_MODE_EL0t:
 123                 exc_offset = LOWER_EL_AArch64_VECTOR;
 124                 break;
 125         default:
 126                 exc_offset = LOWER_EL_AArch32_VECTOR;
 127         }
 128
 129         return vcpu_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
 130 }
 131
 132 static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
 133 {
 134         unsigned long cpsr = *vcpu_cpsr(vcpu);
 135         bool is_aarch32 = vcpu_mode_is_32bit(vcpu);
 136         u32 esr = 0;
 137
 138         *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
 139         *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
 140
 141         *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
 142         *vcpu_spsr(vcpu) = cpsr;
 143
 144         vcpu_sys_reg(vcpu, FAR_EL1) = addr;
 145
 146         /*
 147          * Build an {i,d}abort, depending on the level and the
 148          * instruction set. Report an external synchronous abort.
 149          */
 150         if (kvm_vcpu_trap_il_is32bit(vcpu))
 151                 esr |= ESR_ELx_IL;
 152
 153         /*
 154          * Here, the guest runs in AArch64 mode when in EL1. If we get
 155          * an AArch32 fault, it means we managed to trap an EL0 fault.
 156          */
 157         if (is_aarch32 || (cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t)
 158                 esr |= (ESR_ELx_EC_IABT_LOW << ESR_ELx_EC_SHIFT);
 159         else
 160                 esr |= (ESR_ELx_EC_IABT_CUR << ESR_ELx_EC_SHIFT);
 161
 162         if (!is_iabt)
 163                 esr |= ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT;
 164
 165         vcpu_sys_reg(vcpu, ESR_EL1) = esr | ESR_ELx_FSC_EXTABT;
 166 }
 167
 168 static void inject_undef64(struct kvm_vcpu *vcpu)
 169 {
 170         unsigned long cpsr = *vcpu_cpsr(vcpu);
 171         u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT);
 172
 173         *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu);
 174         *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
 175
 176         *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
 177         *vcpu_spsr(vcpu) = cpsr;
 178
 179         /*
 180          * Build an unknown exception, depending on the instruction
 181          * set.
 182          */
 183         if (kvm_vcpu_trap_il_is32bit(vcpu))
 184                 esr |= ESR_ELx_IL;
 185
 186         vcpu_sys_reg(vcpu, ESR_EL1) = esr;
 187 }
 188
 189 /**
 190  * kvm_inject_dabt - inject a data abort into the guest
 191  * @vcpu: The VCPU to receive the undefined exception
 192  * @addr: The address to report in the DFAR
 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_dabt(struct kvm_vcpu *vcpu, unsigned long addr)
 198 {
 199         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 200                 inject_abt32(vcpu, false, addr);
 201         else
 202                 inject_abt64(vcpu, false, addr);
 203 }
 204
 205 /**
 206  * kvm_inject_pabt - inject a prefetch abort into the guest
 207  * @vcpu: The VCPU to receive the undefined exception
 208  * @addr: The address to report in the DFAR
 209  *
 210  * It is assumed that this code is called from the VCPU thread and that the
 211  * VCPU therefore is not currently executing guest code.
 212  */
 213 void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr)
 214 {
 215         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 216                 inject_abt32(vcpu, true, addr);
 217         else
 218                 inject_abt64(vcpu, true, addr);
 219 }
 220
 221 /**
 222  * kvm_inject_undefined - inject an undefined instruction into the guest
 223  *
 224  * It is assumed that this code is called from the VCPU thread and that the
 225  * VCPU therefore is not currently executing guest code.
 226  */
 227 void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 228 {
 229         if (!(vcpu->arch.hcr_el2 & HCR_RW))
 230                 inject_undef32(vcpu);
 231         else
 232                 inject_undef64(vcpu);
 233 }