virt/kvm/arm/aarch32.c

   1 /*
   2  * (not much of an) Emulation layer for 32bit 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/kvm_hyp.h>
  27
  28 /*
  29  * Table taken from ARMv8 ARM DDI0487B-B, table G1-10.
  30  */
  31 static const u8 return_offsets[8][2] = {
  32         [0] = { 0, 0 },         /* Reset, unused */
  33         [1] = { 4, 2 },         /* Undefined */
  34         [2] = { 0, 0 },         /* SVC, unused */
  35         [3] = { 4, 4 },         /* Prefetch abort */
  36         [4] = { 8, 8 },         /* Data abort */
  37         [5] = { 0, 0 },         /* HVC, unused */
  38         [6] = { 4, 4 },         /* IRQ, unused */
  39         [7] = { 4, 4 },         /* FIQ, unused */
  40 };
  41
  42 static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
  43 {
  44         unsigned long cpsr;
  45         unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
  46         bool is_thumb = (new_spsr_value & PSR_AA32_T_BIT);
  47         u32 return_offset = return_offsets[vect_offset >> 2][is_thumb];
  48         u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
  49
  50         cpsr = mode | PSR_AA32_I_BIT;
  51
  52         if (sctlr & (1 << 30))
  53                 cpsr |= PSR_AA32_T_BIT;
  54         if (sctlr & (1 << 25))
  55                 cpsr |= PSR_AA32_E_BIT;
  56
  57         *vcpu_cpsr(vcpu) = cpsr;
  58
  59         /* Note: These now point to the banked copies */
  60         vcpu_write_spsr(vcpu, new_spsr_value);
  61         *vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
  62
  63         /* Branch to exception vector */
  64         if (sctlr & (1 << 13))
  65                 vect_offset += 0xffff0000;
  66         else /* always have security exceptions */
  67                 vect_offset += vcpu_cp15(vcpu, c12_VBAR);
  68
  69         *vcpu_pc(vcpu) = vect_offset;
  70 }
  71
  72 void kvm_inject_undef32(struct kvm_vcpu *vcpu)
  73 {
  74         prepare_fault32(vcpu, PSR_AA32_MODE_UND, 4);
  75 }
  76
  77 /*
  78  * Modelled after TakeDataAbortException() and TakePrefetchAbortException
  79  * pseudocode.
  80  */
  81 static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
  82                          unsigned long addr)
  83 {
  84         u32 vect_offset;
  85         u32 *far, *fsr;
  86         bool is_lpae;
  87
  88         if (is_pabt) {
  89                 vect_offset = 12;
  90                 far = &vcpu_cp15(vcpu, c6_IFAR);
  91                 fsr = &vcpu_cp15(vcpu, c5_IFSR);
  92         } else { /* !iabt */
  93                 vect_offset = 16;
  94                 far = &vcpu_cp15(vcpu, c6_DFAR);
  95                 fsr = &vcpu_cp15(vcpu, c5_DFSR);
  96         }
  97
  98         prepare_fault32(vcpu, PSR_AA32_MODE_ABT | PSR_AA32_A_BIT, vect_offset);
  99
 100         *far = addr;
 101
 102         /* Give the guest an IMPLEMENTATION DEFINED exception */
 103         is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
 104         if (is_lpae)
 105                 *fsr = 1 << 9 | 0x34;
 106         else
 107                 *fsr = 0x14;
 108 }
 109
 110 void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr)
 111 {
 112         inject_abt32(vcpu, false, addr);
 113 }
 114
 115 void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr)
 116 {
 117         inject_abt32(vcpu, true, addr);
 118 }