arch/mips/kvm/interrupt.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * KVM/MIPS: Interrupt delivery
   7  *
   8  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
   9  * Authors: Sanjay Lal <sanjayl@kymasys.com>
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/err.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/fs.h>
  16 #include <linux/bootmem.h>
  17 #include <asm/page.h>
  18 #include <asm/cacheflush.h>
  19
  20 #include <linux/kvm_host.h>
  21
  22 #include "interrupt.h"
  23
  24 void kvm_mips_queue_irq(struct kvm_vcpu *vcpu, unsigned int priority)
  25 {
  26         set_bit(priority, &vcpu->arch.pending_exceptions);
  27 }
  28
  29 void kvm_mips_dequeue_irq(struct kvm_vcpu *vcpu, unsigned int priority)
  30 {
  31         clear_bit(priority, &vcpu->arch.pending_exceptions);
  32 }
  33
  34 void kvm_mips_queue_timer_int_cb(struct kvm_vcpu *vcpu)
  35 {
  36         /*
  37          * Cause bits to reflect the pending timer interrupt,
  38          * the EXC code will be set when we are actually
  39          * delivering the interrupt:
  40          */
  41         kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
  42
  43         /* Queue up an INT exception for the core */
  44         kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_TIMER);
  45
  46 }
  47
  48 void kvm_mips_dequeue_timer_int_cb(struct kvm_vcpu *vcpu)
  49 {
  50         kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
  51         kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_TIMER);
  52 }
  53
  54 void kvm_mips_queue_io_int_cb(struct kvm_vcpu *vcpu,
  55                               struct kvm_mips_interrupt *irq)
  56 {
  57         int intr = (int)irq->irq;
  58
  59         /*
  60          * Cause bits to reflect the pending IO interrupt,
  61          * the EXC code will be set when we are actually
  62          * delivering the interrupt:
  63          */
  64         switch (intr) {
  65         case 2:
  66                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
  67                 /* Queue up an INT exception for the core */
  68                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IO);
  69                 break;
  70
  71         case 3:
  72                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
  73                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_1);
  74                 break;
  75
  76         case 4:
  77                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
  78                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_2);
  79                 break;
  80
  81         default:
  82                 break;
  83         }
  84
  85 }
  86
  87 void kvm_mips_dequeue_io_int_cb(struct kvm_vcpu *vcpu,
  88                                 struct kvm_mips_interrupt *irq)
  89 {
  90         int intr = (int)irq->irq;
  91
  92         switch (intr) {
  93         case -2:
  94                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
  95                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IO);
  96                 break;
  97
  98         case -3:
  99                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
 100                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_1);
 101                 break;
 102
 103         case -4:
 104                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
 105                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_2);
 106                 break;
 107
 108         default:
 109                 break;
 110         }
 111
 112 }
 113
 114 /* Deliver the interrupt of the corresponding priority, if possible. */
 115 int kvm_mips_irq_deliver_cb(struct kvm_vcpu *vcpu, unsigned int priority,
 116                             u32 cause)
 117 {
 118         int allowed = 0;
 119         u32 exccode;
 120
 121         struct kvm_vcpu_arch *arch = &vcpu->arch;
 122         struct mips_coproc *cop0 = vcpu->arch.cop0;
 123
 124         switch (priority) {
 125         case MIPS_EXC_INT_TIMER:
 126                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 127                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 128                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ5)) {
 129                         allowed = 1;
 130                         exccode = EXCCODE_INT;
 131                 }
 132                 break;
 133
 134         case MIPS_EXC_INT_IO:
 135                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 136                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 137                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ0)) {
 138                         allowed = 1;
 139                         exccode = EXCCODE_INT;
 140                 }
 141                 break;
 142
 143         case MIPS_EXC_INT_IPI_1:
 144                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 145                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 146                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ1)) {
 147                         allowed = 1;
 148                         exccode = EXCCODE_INT;
 149                 }
 150                 break;
 151
 152         case MIPS_EXC_INT_IPI_2:
 153                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 154                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 155                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ2)) {
 156                         allowed = 1;
 157                         exccode = EXCCODE_INT;
 158                 }
 159                 break;
 160
 161         default:
 162                 break;
 163         }
 164
 165         /* Are we allowed to deliver the interrupt ??? */
 166         if (allowed) {
 167                 if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
 168                         /* save old pc */
 169                         kvm_write_c0_guest_epc(cop0, arch->pc);
 170                         kvm_set_c0_guest_status(cop0, ST0_EXL);
 171
 172                         if (cause & CAUSEF_BD)
 173                                 kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
 174                         else
 175                                 kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
 176
 177                         kvm_debug("Delivering INT @ pc %#lx\n", arch->pc);
 178
 179                 } else
 180                         kvm_err("Trying to deliver interrupt when EXL is already set\n");
 181
 182                 kvm_change_c0_guest_cause(cop0, CAUSEF_EXCCODE,
 183                                           (exccode << CAUSEB_EXCCODE));
 184
 185                 /* XXXSL Set PC to the interrupt exception entry point */
 186                 if (kvm_read_c0_guest_cause(cop0) & CAUSEF_IV)
 187                         arch->pc = KVM_GUEST_KSEG0 + 0x200;
 188                 else
 189                         arch->pc = KVM_GUEST_KSEG0 + 0x180;
 190
 191                 clear_bit(priority, &vcpu->arch.pending_exceptions);
 192         }
 193
 194         return allowed;
 195 }
 196
 197 int kvm_mips_irq_clear_cb(struct kvm_vcpu *vcpu, unsigned int priority,
 198                           u32 cause)
 199 {
 200         return 1;
 201 }
 202
 203 void kvm_mips_deliver_interrupts(struct kvm_vcpu *vcpu, u32 cause)
 204 {
 205         unsigned long *pending = &vcpu->arch.pending_exceptions;
 206         unsigned long *pending_clr = &vcpu->arch.pending_exceptions_clr;
 207         unsigned int priority;
 208
 209         if (!(*pending) && !(*pending_clr))
 210                 return;
 211
 212         priority = __ffs(*pending_clr);
 213         while (priority <= MIPS_EXC_MAX) {
 214                 if (kvm_mips_callbacks->irq_clear(vcpu, priority, cause)) {
 215                         if (!KVM_MIPS_IRQ_CLEAR_ALL_AT_ONCE)
 216                                 break;
 217                 }
 218
 219                 priority = find_next_bit(pending_clr,
 220                                          BITS_PER_BYTE * sizeof(*pending_clr),
 221                                          priority + 1);
 222         }
 223
 224         priority = __ffs(*pending);
 225         while (priority <= MIPS_EXC_MAX) {
 226                 if (kvm_mips_callbacks->irq_deliver(vcpu, priority, cause)) {
 227                         if (!KVM_MIPS_IRQ_DELIVER_ALL_AT_ONCE)
 228                                 break;
 229                 }
 230
 231                 priority = find_next_bit(pending,
 232                                          BITS_PER_BYTE * sizeof(*pending),
 233                                          priority + 1);
 234         }
 235
 236 }
 237
 238 int kvm_mips_pending_timer(struct kvm_vcpu *vcpu)
 239 {
 240         return test_bit(MIPS_EXC_INT_TIMER, &vcpu->arch.pending_exceptions);
 241 }