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linux/arch/s390/kvm/sigp.c
Jens Freimann 151104a7b3 KVM: s390: make sigp restart return busy when stop pending 
On reboot the guest sends in smp_send_stop() a sigp stop to all CPUs
except for current CPU.  Then the guest switches to the IPL cpu by
sending a restart to the IPL CPU, followed by a sigp stop to the
current cpu. Since restart is handled by userspace it's possible that
the restart is delivered before the old stop.  This means that the IPL
CPU isn't restarted and we have no running CPUs. So let's make sure
that there is no stop action pending when we do the restart.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-08 14:10:15 +02:00

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/*
* sigp.c - handlinge interprocessor communication
*
* Copyright IBM Corp. 2008,2009
*
* 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>
* Christian Borntraeger <borntraeger@de.ibm.com>
* Christian Ehrhardt <ehrhardt@de.ibm.com>
*/
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <linux/slab.h>
#include "gaccess.h"
#include "kvm-s390.h"
/* sigp order codes */
#define SIGP_SENSE 0x01
#define SIGP_EXTERNAL_CALL 0x02
#define SIGP_EMERGENCY 0x03
#define SIGP_START 0x04
#define SIGP_STOP 0x05
#define SIGP_RESTART 0x06
#define SIGP_STOP_STORE_STATUS 0x09
#define SIGP_INITIAL_CPU_RESET 0x0b
#define SIGP_CPU_RESET 0x0c
#define SIGP_SET_PREFIX 0x0d
#define SIGP_STORE_STATUS_ADDR 0x0e
#define SIGP_SET_ARCH 0x12
#define SIGP_SENSE_RUNNING 0x15
/* cpu status bits */
#define SIGP_STAT_EQUIPMENT_CHECK 0x80000000UL
#define SIGP_STAT_NOT_RUNNING 0x00000400UL
#define SIGP_STAT_INCORRECT_STATE 0x00000200UL
#define SIGP_STAT_INVALID_PARAMETER 0x00000100UL
#define SIGP_STAT_EXT_CALL_PENDING 0x00000080UL
#define SIGP_STAT_STOPPED 0x00000040UL
#define SIGP_STAT_OPERATOR_INTERV 0x00000020UL
#define SIGP_STAT_CHECK_STOP 0x00000010UL
#define SIGP_STAT_INOPERATIVE 0x00000004UL
#define SIGP_STAT_INVALID_ORDER 0x00000002UL
#define SIGP_STAT_RECEIVER_CHECK 0x00000001UL
static int __sigp_sense(struct kvm_vcpu *vcpu, u16 cpu_addr,
u64 *reg)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
spin_lock(&fi->lock);
if (fi->local_int[cpu_addr] == NULL)
rc = 3; /* not operational */
else if (!(atomic_read(fi->local_int[cpu_addr]->cpuflags)
& CPUSTAT_STOPPED)) {
*reg &= 0xffffffff00000000UL;
rc = 1; /* status stored */
} else {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STAT_STOPPED;
rc = 1; /* status stored */
}
spin_unlock(&fi->lock);
VCPU_EVENT(vcpu, 4, "sensed status of cpu %x rc %x", cpu_addr, rc);
return rc;
}
static int __sigp_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li;
struct kvm_s390_interrupt_info *inti;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
inti = kzalloc(sizeof(*inti), GFP_KERNEL);
if (!inti)
return -ENOMEM;
inti->type = KVM_S390_INT_EMERGENCY;
inti->emerg.code = vcpu->vcpu_id;
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = 3; /* not operational */
kfree(inti);
goto unlock;
}
spin_lock_bh(&li->lock);
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
if (waitqueue_active(&li->wq))
wake_up_interruptible(&li->wq);
spin_unlock_bh(&li->lock);
rc = 0; /* order accepted */
VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
unlock:
spin_unlock(&fi->lock);
return rc;
}
static int __sigp_external_call(struct kvm_vcpu *vcpu, u16 cpu_addr)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li;
struct kvm_s390_interrupt_info *inti;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
inti = kzalloc(sizeof(*inti), GFP_KERNEL);
if (!inti)
return -ENOMEM;
inti->type = KVM_S390_INT_EXTERNAL_CALL;
inti->extcall.code = vcpu->vcpu_id;
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = 3; /* not operational */
kfree(inti);
goto unlock;
}
spin_lock_bh(&li->lock);
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
atomic_set_mask(CPUSTAT_EXT_INT, li->cpuflags);
if (waitqueue_active(&li->wq))
wake_up_interruptible(&li->wq);
spin_unlock_bh(&li->lock);
rc = 0; /* order accepted */
VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x", cpu_addr);
unlock:
spin_unlock(&fi->lock);
return rc;
}
static int __inject_sigp_stop(struct kvm_s390_local_interrupt *li, int action)
{
struct kvm_s390_interrupt_info *inti;
inti = kzalloc(sizeof(*inti), GFP_ATOMIC);
if (!inti)
return -ENOMEM;
inti->type = KVM_S390_SIGP_STOP;
spin_lock_bh(&li->lock);
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
li->action_bits |= action;
if (waitqueue_active(&li->wq))
wake_up_interruptible(&li->wq);
spin_unlock_bh(&li->lock);
return 0; /* order accepted */
}
static int __sigp_stop(struct kvm_vcpu *vcpu, u16 cpu_addr, int action)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = 3; /* not operational */
goto unlock;
}
rc = __inject_sigp_stop(li, action);
unlock:
spin_unlock(&fi->lock);
VCPU_EVENT(vcpu, 4, "sent sigp stop to cpu %x", cpu_addr);
return rc;
}
int kvm_s390_inject_sigp_stop(struct kvm_vcpu *vcpu, int action)
{
struct kvm_s390_local_interrupt *li = &vcpu->arch.local_int;
return __inject_sigp_stop(li, action);
}
static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
{
int rc;
switch (parameter & 0xff) {
case 0:
rc = 3; /* not operational */
break;
case 1:
case 2:
rc = 0; /* order accepted */
break;
default:
rc = -EOPNOTSUPP;
}
return rc;
}
static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address,
u64 *reg)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li = NULL;
struct kvm_s390_interrupt_info *inti;
int rc;
u8 tmp;
/* make sure that the new value is valid memory */
address = address & 0x7fffe000u;
if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1)) {
*reg |= SIGP_STAT_INVALID_PARAMETER;
return 1; /* invalid parameter */
}
inti = kzalloc(sizeof(*inti), GFP_KERNEL);
if (!inti)
return 2; /* busy */
spin_lock(&fi->lock);
if (cpu_addr < KVM_MAX_VCPUS)
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = 1; /* incorrect state */
*reg &= SIGP_STAT_INCORRECT_STATE;
kfree(inti);
goto out_fi;
}
spin_lock_bh(&li->lock);
/* cpu must be in stopped state */
if (!(atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
rc = 1; /* incorrect state */
*reg &= SIGP_STAT_INCORRECT_STATE;
kfree(inti);
goto out_li;
}
inti->type = KVM_S390_SIGP_SET_PREFIX;
inti->prefix.address = address;
list_add_tail(&inti->list, &li->list);
atomic_set(&li->active, 1);
if (waitqueue_active(&li->wq))
wake_up_interruptible(&li->wq);
rc = 0; /* order accepted */
VCPU_EVENT(vcpu, 4, "set prefix of cpu %02x to %x", cpu_addr, address);
out_li:
spin_unlock_bh(&li->lock);
out_fi:
spin_unlock(&fi->lock);
return rc;
}
static int __sigp_sense_running(struct kvm_vcpu *vcpu, u16 cpu_addr,
u64 *reg)
{
int rc;
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
spin_lock(&fi->lock);
if (fi->local_int[cpu_addr] == NULL)
rc = 3; /* not operational */
else {
if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
& CPUSTAT_RUNNING) {
/* running */
rc = 1;
} else {
/* not running */
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STAT_NOT_RUNNING;
rc = 0;
}
}
spin_unlock(&fi->lock);
VCPU_EVENT(vcpu, 4, "sensed running status of cpu %x rc %x", cpu_addr,
rc);
return rc;
}
static int __sigp_restart(struct kvm_vcpu *vcpu, u16 cpu_addr)
{
int rc = 0;
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li;
if (cpu_addr >= KVM_MAX_VCPUS)
return 3; /* not operational */
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = 3; /* not operational */
goto out;
}
spin_lock_bh(&li->lock);
if (li->action_bits & ACTION_STOP_ON_STOP)
rc = 2; /* busy */
else
VCPU_EVENT(vcpu, 4, "sigp restart %x to handle userspace",
cpu_addr);
spin_unlock_bh(&li->lock);
out:
spin_unlock(&fi->lock);
return rc;
}
int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu)
{
int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4;
int r3 = vcpu->arch.sie_block->ipa & 0x000f;
int base2 = vcpu->arch.sie_block->ipb >> 28;
int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
u32 parameter;
u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
u8 order_code;
int rc;
/* sigp in userspace can exit */
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu,
PGM_PRIVILEGED_OPERATION);
order_code = disp2;
if (base2)
order_code += vcpu->run->s.regs.gprs[base2];
if (r1 % 2)
parameter = vcpu->run->s.regs.gprs[r1];
else
parameter = vcpu->run->s.regs.gprs[r1 + 1];
switch (order_code) {
case SIGP_SENSE:
vcpu->stat.instruction_sigp_sense++;
rc = __sigp_sense(vcpu, cpu_addr,
&vcpu->run->s.regs.gprs[r1]);
break;
case SIGP_EXTERNAL_CALL:
vcpu->stat.instruction_sigp_external_call++;
rc = __sigp_external_call(vcpu, cpu_addr);
break;
case SIGP_EMERGENCY:
vcpu->stat.instruction_sigp_emergency++;
rc = __sigp_emergency(vcpu, cpu_addr);
break;
case SIGP_STOP:
vcpu->stat.instruction_sigp_stop++;
rc = __sigp_stop(vcpu, cpu_addr, ACTION_STOP_ON_STOP);
break;
case SIGP_STOP_STORE_STATUS:
vcpu->stat.instruction_sigp_stop++;
rc = __sigp_stop(vcpu, cpu_addr, ACTION_STORE_ON_STOP);
break;
case SIGP_SET_ARCH:
vcpu->stat.instruction_sigp_arch++;
rc = __sigp_set_arch(vcpu, parameter);
break;
case SIGP_SET_PREFIX:
vcpu->stat.instruction_sigp_prefix++;
rc = __sigp_set_prefix(vcpu, cpu_addr, parameter,
&vcpu->run->s.regs.gprs[r1]);
break;
case SIGP_SENSE_RUNNING:
vcpu->stat.instruction_sigp_sense_running++;
rc = __sigp_sense_running(vcpu, cpu_addr,
&vcpu->run->s.regs.gprs[r1]);
break;
case SIGP_RESTART:
vcpu->stat.instruction_sigp_restart++;
rc = __sigp_restart(vcpu, cpu_addr);
if (rc == 2) /* busy */
break;
/* user space must know about restart */
default:
return -EOPNOTSUPP;
}
if (rc < 0)
return rc;
vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
vcpu->arch.sie_block->gpsw.mask |= (rc & 3ul) << 44;
return 0;
}
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