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/module.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/fs.h>
  17 #include <linux/bootmem.h>
  18 #include <asm/page.h>
  19 #include <asm/cacheflush.h>
  20
  21 #include <linux/kvm_host.h>
  22
  23 #include "interrupt.h"
  24
  25 void kvm_mips_queue_irq(struct kvm_vcpu *vcpu, unsigned int priority)
  26 {
  27         set_bit(priority, &vcpu->arch.pending_exceptions);
  28 }
  29
  30 void kvm_mips_dequeue_irq(struct kvm_vcpu *vcpu, unsigned int priority)
  31 {
  32         clear_bit(priority, &vcpu->arch.pending_exceptions);
  33 }
  34
  35 void kvm_mips_queue_timer_int_cb(struct kvm_vcpu *vcpu)
  36 {
  37         /*
  38          * Cause bits to reflect the pending timer interrupt,
  39          * the EXC code will be set when we are actually
  40          * delivering the interrupt:
  41          */
  42         kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
  43
  44         /* Queue up an INT exception for the core */
  45         kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_TIMER);
  46
  47 }
  48
  49 void kvm_mips_dequeue_timer_int_cb(struct kvm_vcpu *vcpu)
  50 {
  51         kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ5 | C_TI));
  52         kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_TIMER);
  53 }
  54
  55 void kvm_mips_queue_io_int_cb(struct kvm_vcpu *vcpu,
  56                               struct kvm_mips_interrupt *irq)
  57 {
  58         int intr = (int)irq->irq;
  59
  60         /*
  61          * Cause bits to reflect the pending IO interrupt,
  62          * the EXC code will be set when we are actually
  63          * delivering the interrupt:
  64          */
  65         switch (intr) {
  66         case 2:
  67                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
  68                 /* Queue up an INT exception for the core */
  69                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IO);
  70                 break;
  71
  72         case 3:
  73                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
  74                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_1);
  75                 break;
  76
  77         case 4:
  78                 kvm_set_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
  79                 kvm_mips_queue_irq(vcpu, MIPS_EXC_INT_IPI_2);
  80                 break;
  81
  82         default:
  83                 break;
  84         }
  85
  86 }
  87
  88 void kvm_mips_dequeue_io_int_cb(struct kvm_vcpu *vcpu,
  89                                 struct kvm_mips_interrupt *irq)
  90 {
  91         int intr = (int)irq->irq;
  92
  93         switch (intr) {
  94         case -2:
  95                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ0));
  96                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IO);
  97                 break;
  98
  99         case -3:
 100                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ1));
 101                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_1);
 102                 break;
 103
 104         case -4:
 105                 kvm_clear_c0_guest_cause(vcpu->arch.cop0, (C_IRQ2));
 106                 kvm_mips_dequeue_irq(vcpu, MIPS_EXC_INT_IPI_2);
 107                 break;
 108
 109         default:
 110                 break;
 111         }
 112
 113 }
 114
 115 /* Deliver the interrupt of the corresponding priority, if possible. */
 116 int kvm_mips_irq_deliver_cb(struct kvm_vcpu *vcpu, unsigned int priority,
 117                             u32 cause)
 118 {
 119         int allowed = 0;
 120         u32 exccode;
 121
 122         struct kvm_vcpu_arch *arch = &vcpu->arch;
 123         struct mips_coproc *cop0 = vcpu->arch.cop0;
 124
 125         switch (priority) {
 126         case MIPS_EXC_INT_TIMER:
 127                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 128                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 129                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ5)) {
 130                         allowed = 1;
 131                         exccode = EXCCODE_INT;
 132                 }
 133                 break;
 134
 135         case MIPS_EXC_INT_IO:
 136                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 137                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 138                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ0)) {
 139                         allowed = 1;
 140                         exccode = EXCCODE_INT;
 141                 }
 142                 break;
 143
 144         case MIPS_EXC_INT_IPI_1:
 145                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 146                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 147                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ1)) {
 148                         allowed = 1;
 149                         exccode = EXCCODE_INT;
 150                 }
 151                 break;
 152
 153         case MIPS_EXC_INT_IPI_2:
 154                 if ((kvm_read_c0_guest_status(cop0) & ST0_IE)
 155                     && (!(kvm_read_c0_guest_status(cop0) & (ST0_EXL | ST0_ERL)))
 156                     && (kvm_read_c0_guest_status(cop0) & IE_IRQ2)) {
 157                         allowed = 1;
 158                         exccode = EXCCODE_INT;
 159                 }
 160                 break;
 161
 162         default:
 163                 break;
 164         }
 165
 166         /* Are we allowed to deliver the interrupt ??? */
 167         if (allowed) {
 168                 if ((kvm_read_c0_guest_status(cop0) & ST0_EXL) == 0) {
 169                         /* save old pc */
 170                         kvm_write_c0_guest_epc(cop0, arch->pc);
 171                         kvm_set_c0_guest_status(cop0, ST0_EXL);
 172
 173                         if (cause & CAUSEF_BD)
 174                                 kvm_set_c0_guest_cause(cop0, CAUSEF_BD);
 175                         else
 176                                 kvm_clear_c0_guest_cause(cop0, CAUSEF_BD);
 177
 178                         kvm_debug("Delivering INT @ pc %#lx\n", arch->pc);
 179
 180                 } else
 181                         kvm_err("Trying to deliver interrupt when EXL is already set\n");
 182
 183                 kvm_change_c0_guest_cause(cop0, CAUSEF_EXCCODE,
 184                                           (exccode << CAUSEB_EXCCODE));
 185
 186                 /* XXXSL Set PC to the interrupt exception entry point */
 187                 if (kvm_read_c0_guest_cause(cop0) & CAUSEF_IV)
 188                         arch->pc = KVM_GUEST_KSEG0 + 0x200;
 189                 else
 190                         arch->pc = KVM_GUEST_KSEG0 + 0x180;
 191
 192                 clear_bit(priority, &vcpu->arch.pending_exceptions);
 193         }
 194
 195         return allowed;
 196 }
 197
 198 int kvm_mips_irq_clear_cb(struct kvm_vcpu *vcpu, unsigned int priority,
 199                           u32 cause)
 200 {
 201         return 1;
 202 }
 203
 204 void kvm_mips_deliver_interrupts(struct kvm_vcpu *vcpu, u32 cause)
 205 {
 206         unsigned long *pending = &vcpu->arch.pending_exceptions;
 207         unsigned long *pending_clr = &vcpu->arch.pending_exceptions_clr;
 208         unsigned int priority;
 209
 210         if (!(*pending) && !(*pending_clr))
 211                 return;
 212
 213         priority = __ffs(*pending_clr);
 214         while (priority <= MIPS_EXC_MAX) {
 215                 if (kvm_mips_callbacks->irq_clear(vcpu, priority, cause)) {
 216                         if (!KVM_MIPS_IRQ_CLEAR_ALL_AT_ONCE)
 217                                 break;
 218                 }
 219
 220                 priority = find_next_bit(pending_clr,
 221                                          BITS_PER_BYTE * sizeof(*pending_clr),
 222                                          priority + 1);
 223         }
 224
 225         priority = __ffs(*pending);
 226         while (priority <= MIPS_EXC_MAX) {
 227                 if (kvm_mips_callbacks->irq_deliver(vcpu, priority, cause)) {
 228                         if (!KVM_MIPS_IRQ_DELIVER_ALL_AT_ONCE)
 229                                 break;
 230                 }
 231
 232                 priority = find_next_bit(pending,
 233                                          BITS_PER_BYTE * sizeof(*pending),
 234                                          priority + 1);
 235         }
 236
 237 }
 238
 239 int kvm_mips_pending_timer(struct kvm_vcpu *vcpu)
 240 {
 241         return test_bit(MIPS_EXC_INT_TIMER, &vcpu->arch.pending_exceptions);
 242 }