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interrupt.c

/*
 * interrupt.c - handling kvm guest interrupts
 *
 * Copyright IBM Corp. 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 */

#include <asm/lowcore.h>
#include <asm/uaccess.h>
#include <linux/kvm_host.h>
#include <linux/signal.h>
#include "kvm-s390.h"
#include "gaccess.h"

static int psw_extint_disabled(struct kvm_vcpu *vcpu)
{
      return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT);
}

static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
{
      if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
          (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO) ||
          (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT))
            return 0;
      return 1;
}

static int __interrupt_is_deliverable(struct kvm_vcpu *vcpu,
                              struct kvm_s390_interrupt_info *inti)
{
      switch (inti->type) {
      case KVM_S390_INT_EMERGENCY:
            if (psw_extint_disabled(vcpu))
                  return 0;
            if (vcpu->arch.sie_block->gcr[0] & 0x4000ul)
                  return 1;
            return 0;
      case KVM_S390_INT_SERVICE:
            if (psw_extint_disabled(vcpu))
                  return 0;
            if (vcpu->arch.sie_block->gcr[0] & 0x200ul)
                  return 1;
            return 0;
      case KVM_S390_INT_VIRTIO:
            if (psw_extint_disabled(vcpu))
                  return 0;
            if (vcpu->arch.sie_block->gcr[0] & 0x200ul)
                  return 1;
            return 0;
      case KVM_S390_PROGRAM_INT:
      case KVM_S390_SIGP_STOP:
      case KVM_S390_SIGP_SET_PREFIX:
      case KVM_S390_RESTART:
            return 1;
      default:
            BUG();
      }
      return 0;
}

static void __set_cpu_idle(struct kvm_vcpu *vcpu)
{
      BUG_ON(vcpu->vcpu_id > KVM_MAX_VCPUS - 1);
      atomic_set_mask(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
      set_bit(vcpu->vcpu_id, vcpu->arch.local_int.float_int->idle_mask);
}

static void __unset_cpu_idle(struct kvm_vcpu *vcpu)
{
      BUG_ON(vcpu->vcpu_id > KVM_MAX_VCPUS - 1);
      atomic_clear_mask(CPUSTAT_WAIT, &vcpu->arch.sie_block->cpuflags);
      clear_bit(vcpu->vcpu_id, vcpu->arch.local_int.float_int->idle_mask);
}

static void __reset_intercept_indicators(struct kvm_vcpu *vcpu)
{
      atomic_clear_mask(CPUSTAT_ECALL_PEND |
            CPUSTAT_IO_INT | CPUSTAT_EXT_INT | CPUSTAT_STOP_INT,
            &vcpu->arch.sie_block->cpuflags);
      vcpu->arch.sie_block->lctl = 0x0000;
}

static void __set_cpuflag(struct kvm_vcpu *vcpu, u32 flag)
{
      atomic_set_mask(flag, &vcpu->arch.sie_block->cpuflags);
}

static void __set_intercept_indicator(struct kvm_vcpu *vcpu,
                              struct kvm_s390_interrupt_info *inti)
{
      switch (inti->type) {
      case KVM_S390_INT_EMERGENCY:
      case KVM_S390_INT_SERVICE:
      case KVM_S390_INT_VIRTIO:
            if (psw_extint_disabled(vcpu))
                  __set_cpuflag(vcpu, CPUSTAT_EXT_INT);
            else
                  vcpu->arch.sie_block->lctl |= LCTL_CR0;
            break;
      case KVM_S390_SIGP_STOP:
            __set_cpuflag(vcpu, CPUSTAT_STOP_INT);
            break;
      default:
            BUG();
      }
}

static void __do_deliver_interrupt(struct kvm_vcpu *vcpu,
                           struct kvm_s390_interrupt_info *inti)
{
      const unsigned short table[] = { 2, 4, 4, 6 };
      int rc, exception = 0;

      switch (inti->type) {
      case KVM_S390_INT_EMERGENCY:
            VCPU_EVENT(vcpu, 4, "%s", "interrupt: sigp emerg");
            vcpu->stat.deliver_emergency_signal++;
            rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1201);
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
                   &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
                  __LC_EXT_NEW_PSW, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;
            break;

      case KVM_S390_INT_SERVICE:
            VCPU_EVENT(vcpu, 4, "interrupt: sclp parm:%x",
                     inti->ext.ext_params);
            vcpu->stat.deliver_service_signal++;
            rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2401);
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
                   &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
                  __LC_EXT_NEW_PSW, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
            if (rc == -EFAULT)
                  exception = 1;
            break;

      case KVM_S390_INT_VIRTIO:
            VCPU_EVENT(vcpu, 4, "interrupt: virtio parm:%x,parm64:%lx",
                     inti->ext.ext_params, inti->ext.ext_params2);
            vcpu->stat.deliver_virtio_interrupt++;
            rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x2603);
            if (rc == -EFAULT)
                  exception = 1;

            rc = put_guest_u16(vcpu, __LC_CPU_ADDRESS, 0x0d00);
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
                   &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
                  __LC_EXT_NEW_PSW, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = put_guest_u32(vcpu, __LC_EXT_PARAMS, inti->ext.ext_params);
            if (rc == -EFAULT)
                  exception = 1;

            rc = put_guest_u64(vcpu, __LC_PFAULT_INTPARM,
                  inti->ext.ext_params2);
            if (rc == -EFAULT)
                  exception = 1;
            break;

      case KVM_S390_SIGP_STOP:
            VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu stop");
            vcpu->stat.deliver_stop_signal++;
            __set_intercept_indicator(vcpu, inti);
            break;

      case KVM_S390_SIGP_SET_PREFIX:
            VCPU_EVENT(vcpu, 4, "interrupt: set prefix to %x",
                     inti->prefix.address);
            vcpu->stat.deliver_prefix_signal++;
            vcpu->arch.sie_block->prefix = inti->prefix.address;
            vcpu->arch.sie_block->ihcpu = 0xffff;
            break;

      case KVM_S390_RESTART:
            VCPU_EVENT(vcpu, 4, "%s", "interrupt: cpu restart");
            vcpu->stat.deliver_restart_signal++;
            rc = copy_to_guest(vcpu, offsetof(struct _lowcore,
              restart_old_psw), &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
                  offsetof(struct _lowcore, restart_psw), sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;
            break;

      case KVM_S390_PROGRAM_INT:
            VCPU_EVENT(vcpu, 4, "interrupt: pgm check code:%x, ilc:%x",
                     inti->pgm.code,
                     table[vcpu->arch.sie_block->ipa >> 14]);
            vcpu->stat.deliver_program_int++;
            rc = put_guest_u16(vcpu, __LC_PGM_INT_CODE, inti->pgm.code);
            if (rc == -EFAULT)
                  exception = 1;

            rc = put_guest_u16(vcpu, __LC_PGM_ILC,
                  table[vcpu->arch.sie_block->ipa >> 14]);
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_to_guest(vcpu, __LC_PGM_OLD_PSW,
                   &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;

            rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
                  __LC_PGM_NEW_PSW, sizeof(psw_t));
            if (rc == -EFAULT)
                  exception = 1;
            break;

      default:
            BUG();
      }
      if (exception) {
            printk("kvm: The guest lowcore is not mapped during interrupt "
                  "delivery, killing userspace\n");
            do_exit(SIGKILL);
      }
}

static int __try_deliver_ckc_interrupt(struct kvm_vcpu *vcpu)
{
      int rc, exception = 0;

      if (psw_extint_disabled(vcpu))
            return 0;
      if (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))
            return 0;
      rc = put_guest_u16(vcpu, __LC_EXT_INT_CODE, 0x1004);
      if (rc == -EFAULT)
            exception = 1;
      rc = copy_to_guest(vcpu, __LC_EXT_OLD_PSW,
             &vcpu->arch.sie_block->gpsw, sizeof(psw_t));
      if (rc == -EFAULT)
            exception = 1;
      rc = copy_from_guest(vcpu, &vcpu->arch.sie_block->gpsw,
            __LC_EXT_NEW_PSW, sizeof(psw_t));
      if (rc == -EFAULT)
            exception = 1;
      if (exception) {
            printk("kvm: The guest lowcore is not mapped during interrupt "
                  "delivery, killing userspace\n");
            do_exit(SIGKILL);
      }
      return 1;
}

int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu)
{
      struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
      struct kvm_s390_float_interrupt *fi = vcpu->arch.local_int.float_int;
      struct kvm_s390_interrupt_info  *inti;
      int rc = 0;

      if (atomic_read(&li->active)) {
            spin_lock_bh(&li->lock);
            list_for_each_entry(inti, &li->list, list)
                  if (__interrupt_is_deliverable(vcpu, inti)) {
                        rc = 1;
                        break;
                  }
            spin_unlock_bh(&li->lock);
      }

      if ((!rc) && atomic_read(&fi->active)) {
            spin_lock_bh(&fi->lock);
            list_for_each_entry(inti, &fi->list, list)
                  if (__interrupt_is_deliverable(vcpu, inti)) {
                        rc = 1;
                        break;
                  }
            spin_unlock_bh(&fi->lock);
      }

      if ((!rc) && (vcpu->arch.sie_block->ckc <
            get_clock() + vcpu->arch.sie_block->epoch)) {
            if ((!psw_extint_disabled(vcpu)) &&
                  (vcpu->arch.sie_block->gcr[0] & 0x800ul))
                  rc = 1;
      }

      return rc;
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
      return 0;
}

int kvm_s390_handle_wait(struct kvm_vcpu *vcpu)
{
      u64 now, sltime;
      DECLARE_WAITQUEUE(wait, current);

      vcpu->stat.exit_wait_state++;
      if (kvm_cpu_has_interrupt(vcpu))
            return 0;

      __set_cpu_idle(vcpu);
      spin_lock_bh(&vcpu->arch.local_int.lock);
      vcpu->arch.local_int.timer_due = 0;
      spin_unlock_bh(&vcpu->arch.local_int.lock);

      if (psw_interrupts_disabled(vcpu)) {
            VCPU_EVENT(vcpu, 3, "%s", "disabled wait");
            __unset_cpu_idle(vcpu);
            return -ENOTSUPP; /* disabled wait */
      }

      if (psw_extint_disabled(vcpu) ||
          (!(vcpu->arch.sie_block->gcr[0] & 0x800ul))) {
            VCPU_EVENT(vcpu, 3, "%s", "enabled wait w/o timer");
            goto no_timer;
      }

      now = get_clock() + vcpu->arch.sie_block->epoch;
      if (vcpu->arch.sie_block->ckc < now) {
            __unset_cpu_idle(vcpu);
            return 0;
      }

      sltime = (vcpu->arch.sie_block->ckc - now) / (0xf4240000ul / HZ) + 1;

      vcpu->arch.ckc_timer.expires = jiffies + sltime;

      add_timer(&vcpu->arch.ckc_timer);
      VCPU_EVENT(vcpu, 5, "enabled wait timer:%lx jiffies", sltime);
no_timer:
      spin_lock_bh(&vcpu->arch.local_int.float_int->lock);
      spin_lock_bh(&vcpu->arch.local_int.lock);
      add_wait_queue(&vcpu->arch.local_int.wq, &wait);
      while (list_empty(&vcpu->arch.local_int.list) &&
            list_empty(&vcpu->arch.local_int.float_int->list) &&
            (!vcpu->arch.local_int.timer_due) &&
            !signal_pending(current)) {
            set_current_state(TASK_INTERRUPTIBLE);
            spin_unlock_bh(&vcpu->arch.local_int.lock);
            spin_unlock_bh(&vcpu->arch.local_int.float_int->lock);
            vcpu_put(vcpu);
            schedule();
            vcpu_load(vcpu);
            spin_lock_bh(&vcpu->arch.local_int.float_int->lock);
            spin_lock_bh(&vcpu->arch.local_int.lock);
      }
      __unset_cpu_idle(vcpu);
      __set_current_state(TASK_RUNNING);
      remove_wait_queue(&vcpu->wq, &wait);
      spin_unlock_bh(&vcpu->arch.local_int.lock);
      spin_unlock_bh(&vcpu->arch.local_int.float_int->lock);
      del_timer(&vcpu->arch.ckc_timer);
      return 0;
}

void kvm_s390_idle_wakeup(unsigned long data)
{
      struct kvm_vcpu *vcpu = (struct kvm_vcpu *)data;

      spin_lock_bh(&vcpu->arch.local_int.lock);
      vcpu->arch.local_int.timer_due = 1;
      if (waitqueue_active(&vcpu->arch.local_int.wq))
            wake_up_interruptible(&vcpu->arch.local_int.wq);
      spin_unlock_bh(&vcpu->arch.local_int.lock);
}


void kvm_s390_deliver_pending_interrupts(struct kvm_vcpu *vcpu)
{
      struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
      struct kvm_s390_float_interrupt *fi = vcpu->arch.local_int.float_int;
      struct kvm_s390_interrupt_info  *n, *inti = NULL;
      int deliver;

      __reset_intercept_indicators(vcpu);
      if (atomic_read(&li->active)) {
            do {
                  deliver = 0;
                  spin_lock_bh(&li->lock);
                  list_for_each_entry_safe(inti, n, &li->list, list) {
                        if (__interrupt_is_deliverable(vcpu, inti)) {
                              list_del(&inti->list);
                              deliver = 1;
                              break;
                        }
                        __set_intercept_indicator(vcpu, inti);
                  }
                  if (list_empty(&li->list))
                        atomic_set(&li->active, 0);
                  spin_unlock_bh(&li->lock);
                  if (deliver) {
                        __do_deliver_interrupt(vcpu, inti);
                        kfree(inti);
                  }
            } while (deliver);
      }

      if ((vcpu->arch.sie_block->ckc <
            get_clock() + vcpu->arch.sie_block->epoch))
            __try_deliver_ckc_interrupt(vcpu);

      if (atomic_read(&fi->active)) {
            do {
                  deliver = 0;
                  spin_lock_bh(&fi->lock);
                  list_for_each_entry_safe(inti, n, &fi->list, list) {
                        if (__interrupt_is_deliverable(vcpu, inti)) {
                              list_del(&inti->list);
                              deliver = 1;
                              break;
                        }
                        __set_intercept_indicator(vcpu, inti);
                  }
                  if (list_empty(&fi->list))
                        atomic_set(&fi->active, 0);
                  spin_unlock_bh(&fi->lock);
                  if (deliver) {
                        __do_deliver_interrupt(vcpu, inti);
                        kfree(inti);
                  }
            } while (deliver);
      }
}

int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code)
{
      struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
      struct kvm_s390_interrupt_info *inti;

      inti = kzalloc(sizeof(*inti), GFP_KERNEL);
      if (!inti)
            return -ENOMEM;

      inti->type = KVM_S390_PROGRAM_INT;;
      inti->pgm.code = code;

      VCPU_EVENT(vcpu, 3, "inject: program check %d (from kernel)", code);
      spin_lock_bh(&li->lock);
      list_add(&inti->list, &li->list);
      atomic_set(&li->active, 1);
      BUG_ON(waitqueue_active(&li->wq));
      spin_unlock_bh(&li->lock);
      return 0;
}

int kvm_s390_inject_vm(struct kvm *kvm,
                   struct kvm_s390_interrupt *s390int)
{
      struct kvm_s390_local_interrupt *li;
      struct kvm_s390_float_interrupt *fi;
      struct kvm_s390_interrupt_info *inti;
      int sigcpu;

      inti = kzalloc(sizeof(*inti), GFP_KERNEL);
      if (!inti)
            return -ENOMEM;

      switch (s390int->type) {
      case KVM_S390_INT_VIRTIO:
            VM_EVENT(kvm, 5, "inject: virtio parm:%x,parm64:%lx",
                   s390int->parm, s390int->parm64);
            inti->type = s390int->type;
            inti->ext.ext_params = s390int->parm;
            inti->ext.ext_params2 = s390int->parm64;
            break;
      case KVM_S390_INT_SERVICE:
            VM_EVENT(kvm, 5, "inject: sclp parm:%x", s390int->parm);
            inti->type = s390int->type;
            inti->ext.ext_params = s390int->parm;
            break;
      case KVM_S390_PROGRAM_INT:
      case KVM_S390_SIGP_STOP:
      case KVM_S390_INT_EMERGENCY:
      default:
            kfree(inti);
            return -EINVAL;
      }

      mutex_lock(&kvm->lock);
      fi = &kvm->arch.float_int;
      spin_lock_bh(&fi->lock);
      list_add_tail(&inti->list, &fi->list);
      atomic_set(&fi->active, 1);
      sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS);
      if (sigcpu == KVM_MAX_VCPUS) {
            do {
                  sigcpu = fi->next_rr_cpu++;
                  if (sigcpu == KVM_MAX_VCPUS)
                        sigcpu = fi->next_rr_cpu = 0;
            } while (fi->local_int[sigcpu] == NULL);
      }
      li = fi->local_int[sigcpu];
      spin_lock_bh(&li->lock);
      atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
      if (waitqueue_active(&li->wq))
            wake_up_interruptible(&li->wq);
      spin_unlock_bh(&li->lock);
      spin_unlock_bh(&fi->lock);
      mutex_unlock(&kvm->lock);
      return 0;
}

int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
                   struct kvm_s390_interrupt *s390int)
{
      struct kvm_s390_local_interrupt *li;
      struct kvm_s390_interrupt_info *inti;

      inti = kzalloc(sizeof(*inti), GFP_KERNEL);
      if (!inti)
            return -ENOMEM;

      switch (s390int->type) {
      case KVM_S390_PROGRAM_INT:
            if (s390int->parm & 0xffff0000) {
                  kfree(inti);
                  return -EINVAL;
            }
            inti->type = s390int->type;
            inti->pgm.code = s390int->parm;
            VCPU_EVENT(vcpu, 3, "inject: program check %d (from user)",
                     s390int->parm);
            break;
      case KVM_S390_SIGP_STOP:
      case KVM_S390_RESTART:
      case KVM_S390_SIGP_SET_PREFIX:
      case KVM_S390_INT_EMERGENCY:
            VCPU_EVENT(vcpu, 3, "inject: type %x", s390int->type);
            inti->type = s390int->type;
            break;
      case KVM_S390_INT_VIRTIO:
      case KVM_S390_INT_SERVICE:
      default:
            kfree(inti);
            return -EINVAL;
      }

      mutex_lock(&vcpu->kvm->lock);
      li = &vcpu->arch.local_int;
      spin_lock_bh(&li->lock);
      if (inti->type == KVM_S390_PROGRAM_INT)
            list_add(&inti->list, &li->list);
      else
            list_add_tail(&inti->list, &li->list);
      atomic_set(&li->active, 1);
      if (inti->type == KVM_S390_SIGP_STOP)
            li->action_bits |= ACTION_STOP_ON_STOP;
      atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
      if (waitqueue_active(&li->wq))
            wake_up_interruptible(&vcpu->arch.local_int.wq);
      spin_unlock_bh(&li->lock);
      mutex_unlock(&vcpu->kvm->lock);
      return 0;
}

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