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linux/arch/s390/kvm/sigp.c
Thomas Huth cc92d6dea1 KVM: s390: Reworked SIGP RESTART order 
When SIGP RESTART detected an illegal CPU address, there is no need to
drop to userspace, we can return CC3 to the guest directly instead.
Also renamed __sigp_restart() to sigp_check_callable() (since this
is a better description of what the function is really doing) and
moved a string specific to RESTART to the calling place instead, so
that this function gets usable by other SIGP orders, too.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2013-12-11 19:04:58 +01:00

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/*
* handling interprocessor communication
*
* Copyright IBM Corp. 2008, 2013
*
* 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 <asm/sigp.h>
#include "gaccess.h"
#include "kvm-s390.h"
#include "trace.h"
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 SIGP_CC_NOT_OPERATIONAL;
spin_lock(&fi->lock);
if (fi->local_int[cpu_addr] == NULL)
rc = SIGP_CC_NOT_OPERATIONAL;
else if (!(atomic_read(fi->local_int[cpu_addr]->cpuflags)
& (CPUSTAT_ECALL_PEND | CPUSTAT_STOPPED)))
rc = SIGP_CC_ORDER_CODE_ACCEPTED;
else {
*reg &= 0xffffffff00000000UL;
if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
& CPUSTAT_ECALL_PEND)
*reg |= SIGP_STATUS_EXT_CALL_PENDING;
if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
& CPUSTAT_STOPPED)
*reg |= SIGP_STATUS_STOPPED;
rc = SIGP_CC_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 SIGP_CC_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 = SIGP_CC_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 = SIGP_CC_ORDER_CODE_ACCEPTED;
VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
unlock:
spin_unlock(&fi->lock);
return rc;
}
static int __sigp_conditional_emergency(struct kvm_vcpu *vcpu, u16 cpu_addr,
u16 asn, u64 *reg)
{
struct kvm_vcpu *dst_vcpu = NULL;
const u64 psw_int_mask = PSW_MASK_IO | PSW_MASK_EXT;
u16 p_asn, s_asn;
psw_t *psw;
u32 flags;
if (cpu_addr < KVM_MAX_VCPUS)
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
flags = atomic_read(&dst_vcpu->arch.sie_block->cpuflags);
psw = &dst_vcpu->arch.sie_block->gpsw;
p_asn = dst_vcpu->arch.sie_block->gcr[4] & 0xffff; /* Primary ASN */
s_asn = dst_vcpu->arch.sie_block->gcr[3] & 0xffff; /* Secondary ASN */
/* Deliver the emergency signal? */
if (!(flags & CPUSTAT_STOPPED)
|| (psw->mask & psw_int_mask) != psw_int_mask
|| ((flags & CPUSTAT_WAIT) && psw->addr != 0)
|| (!(flags & CPUSTAT_WAIT) && (asn == p_asn || asn == s_asn))) {
return __sigp_emergency(vcpu, cpu_addr);
} else {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
return SIGP_CC_STATUS_STORED;
}
}
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 SIGP_CC_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 = SIGP_CC_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 = SIGP_CC_ORDER_CODE_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;
int rc = SIGP_CC_ORDER_CODE_ACCEPTED;
inti = kzalloc(sizeof(*inti), GFP_ATOMIC);
if (!inti)
return -ENOMEM;
inti->type = KVM_S390_SIGP_STOP;
spin_lock_bh(&li->lock);
if ((atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
kfree(inti);
if ((action & ACTION_STORE_ON_STOP) != 0)
rc = -ESHUTDOWN;
goto out;
}
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);
out:
spin_unlock_bh(&li->lock);
return rc;
}
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 SIGP_CC_NOT_OPERATIONAL;
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = SIGP_CC_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);
if ((action & ACTION_STORE_ON_STOP) != 0 && rc == -ESHUTDOWN) {
/* If the CPU has already been stopped, we still have
* to save the status when doing stop-and-store. This
* has to be done after unlocking all spinlocks. */
struct kvm_vcpu *dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
rc = kvm_s390_store_status_unloaded(dst_vcpu,
KVM_S390_STORE_STATUS_NOADDR);
}
return rc;
}
static int __sigp_set_arch(struct kvm_vcpu *vcpu, u32 parameter)
{
int rc;
switch (parameter & 0xff) {
case 0:
rc = SIGP_CC_NOT_OPERATIONAL;
break;
case 1:
case 2:
rc = SIGP_CC_ORDER_CODE_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 &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INVALID_PARAMETER;
return SIGP_CC_STATUS_STORED;
}
inti = kzalloc(sizeof(*inti), GFP_KERNEL);
if (!inti)
return SIGP_CC_BUSY;
spin_lock(&fi->lock);
if (cpu_addr < KVM_MAX_VCPUS)
li = fi->local_int[cpu_addr];
if (li == NULL) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
rc = SIGP_CC_STATUS_STORED;
kfree(inti);
goto out_fi;
}
spin_lock_bh(&li->lock);
/* cpu must be in stopped state */
if (!(atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
rc = SIGP_CC_STATUS_STORED;
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 = SIGP_CC_ORDER_CODE_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_store_status_at_addr(struct kvm_vcpu *vcpu, u16 cpu_id,
u32 addr, u64 *reg)
{
struct kvm_vcpu *dst_vcpu = NULL;
int flags;
int rc;
if (cpu_id < KVM_MAX_VCPUS)
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_id);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
spin_lock_bh(&dst_vcpu->arch.local_int.lock);
flags = atomic_read(dst_vcpu->arch.local_int.cpuflags);
spin_unlock_bh(&dst_vcpu->arch.local_int.lock);
if (!(flags & CPUSTAT_STOPPED)) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INCORRECT_STATE;
return SIGP_CC_STATUS_STORED;
}
addr &= 0x7ffffe00;
rc = kvm_s390_store_status_unloaded(dst_vcpu, addr);
if (rc == -EFAULT) {
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_INVALID_PARAMETER;
rc = SIGP_CC_STATUS_STORED;
}
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 SIGP_CC_NOT_OPERATIONAL;
spin_lock(&fi->lock);
if (fi->local_int[cpu_addr] == NULL)
rc = SIGP_CC_NOT_OPERATIONAL;
else {
if (atomic_read(fi->local_int[cpu_addr]->cpuflags)
& CPUSTAT_RUNNING) {
/* running */
rc = SIGP_CC_ORDER_CODE_ACCEPTED;
} else {
/* not running */
*reg &= 0xffffffff00000000UL;
*reg |= SIGP_STATUS_NOT_RUNNING;
rc = SIGP_CC_STATUS_STORED;
}
}
spin_unlock(&fi->lock);
VCPU_EVENT(vcpu, 4, "sensed running status of cpu %x rc %x", cpu_addr,
rc);
return rc;
}
/* Test whether the destination CPU is available and not busy */
static int sigp_check_callable(struct kvm_vcpu *vcpu, u16 cpu_addr)
{
struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
struct kvm_s390_local_interrupt *li;
int rc = SIGP_CC_ORDER_CODE_ACCEPTED;
if (cpu_addr >= KVM_MAX_VCPUS)
return SIGP_CC_NOT_OPERATIONAL;
spin_lock(&fi->lock);
li = fi->local_int[cpu_addr];
if (li == NULL) {
rc = SIGP_CC_NOT_OPERATIONAL;
goto out;
}
spin_lock_bh(&li->lock);
if (li->action_bits & ACTION_STOP_ON_STOP)
rc = SIGP_CC_BUSY;
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;
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_OP);
order_code = kvm_s390_get_base_disp_rs(vcpu);
if (r1 % 2)
parameter = vcpu->run->s.regs.gprs[r1];
else
parameter = vcpu->run->s.regs.gprs[r1 + 1];
trace_kvm_s390_handle_sigp(vcpu, order_code, cpu_addr, parameter);
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_SIGNAL:
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_AND_STORE_STATUS:
vcpu->stat.instruction_sigp_stop++;
rc = __sigp_stop(vcpu, cpu_addr, ACTION_STORE_ON_STOP |
ACTION_STOP_ON_STOP);
break;
case SIGP_STORE_STATUS_AT_ADDRESS:
rc = __sigp_store_status_at_addr(vcpu, cpu_addr, parameter,
&vcpu->run->s.regs.gprs[r1]);
break;
case SIGP_SET_ARCHITECTURE:
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_COND_EMERGENCY_SIGNAL:
rc = __sigp_conditional_emergency(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_check_callable(vcpu, cpu_addr);
if (rc == SIGP_CC_ORDER_CODE_ACCEPTED) {
VCPU_EVENT(vcpu, 4,
"sigp restart %x to handle userspace",
cpu_addr);
/* user space must know about restart */
rc = -EOPNOTSUPP;
}
break;
default:
return -EOPNOTSUPP;
}
if (rc < 0)
return rc;
kvm_s390_set_psw_cc(vcpu, rc);
return 0;
}
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