linux/arch/s390/kvm/interrupt.c
Marcelo Tosatti 3d80840d96 KVM: hlt emulation should take in-kernel APIC/PIT timers into account
Timers that fire between guest hlt and vcpu_block's add_wait_queue() are
ignored, possibly resulting in hangs.

Also make sure that atomic_inc and waitqueue_active tests happen in the
specified order, otherwise the following race is open:

CPU0                                        CPU1
                                            if (waitqueue_active(wq))
add_wait_queue()
if (!atomic_read(pit_timer->pending))
    schedule()
                                            atomic_inc(pit_timer->pending)

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-04-27 12:04:11 +03:00

592 lines
15 KiB
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 "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 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 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 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) {
VCPU_EVENT(vcpu, 1, "%s", "program exception while delivering"
" interrupt");
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
if (inti->type == KVM_S390_PROGRAM_INT) {
printk(KERN_WARNING "kvm: recursive program check\n");
BUG();
}
}
}
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) {
VCPU_EVENT(vcpu, 1, "%s", "program exception while delivering" \
" ckc interrupt");
kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
return 0;
}
return 1;
}
int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu)
{
struct local_interrupt *li = &vcpu->arch.local_int;
struct float_interrupt *fi = vcpu->arch.local_int.float_int;
struct 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;
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);
__set_cpu_idle(vcpu);
vcpu->arch.local_int.timer_due = 0;
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 local_interrupt *li = &vcpu->arch.local_int;
struct float_interrupt *fi = vcpu->arch.local_int.float_int;
struct 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 local_interrupt *li = &vcpu->arch.local_int;
struct 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 local_interrupt *li;
struct float_interrupt *fi;
struct 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 local_interrupt *li;
struct 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;
}