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linux_dsm_epyc7002/arch/s390/kvm/sigp.c
David Hildenbrand 7dfc63cf97 KVM: s390: allow only one SIGP STOP (AND STORE STATUS) at a time 
A SIGP STOP (AND STORE STATUS) order is complete as soon as the VCPU has been
stopped. This patch makes sure that only one SIGP STOP (AND STORE STATUS) may
be pending at a time (as defined by the architecture). If the action_bits are
still set, a SIGP STOP has been issued but not completed yet. The VCPU is busy
for further SIGP STOP orders.

Also set the CPUSTAT_STOP_INT after the action_bits variable has been modified
(the same order that is used when injecting a KVM_S390_SIGP_STOP from
userspace).

Both changes are needed in preparation for a user space driven VCPU state change
(to avoid race conditions).

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-07-10 14:09:34 +02:00

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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_local_interrupt *li;
struct kvm_vcpu *dst_vcpu = NULL;
int cpuflags;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return SIGP_CC_NOT_OPERATIONAL;
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
li = &dst_vcpu->arch.local_int;
cpuflags = atomic_read(li->cpuflags);
if (!(cpuflags & (CPUSTAT_ECALL_PEND | CPUSTAT_STOPPED)))
rc = SIGP_CC_ORDER_CODE_ACCEPTED;
else {
*reg &= 0xffffffff00000000UL;
if (cpuflags & CPUSTAT_ECALL_PEND)
*reg |= SIGP_STATUS_EXT_CALL_PENDING;
if (cpuflags & CPUSTAT_STOPPED)
*reg |= SIGP_STATUS_STOPPED;
rc = SIGP_CC_STATUS_STORED;
}
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_interrupt s390int = {
.type = KVM_S390_INT_EMERGENCY,
.parm = vcpu->vcpu_id,
};
struct kvm_vcpu *dst_vcpu = NULL;
int rc = 0;
if (cpu_addr < KVM_MAX_VCPUS)
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
rc = kvm_s390_inject_vcpu(dst_vcpu, &s390int);
if (!rc)
VCPU_EVENT(vcpu, 4, "sent sigp emerg to cpu %x", cpu_addr);
return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
}
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_interrupt s390int = {
.type = KVM_S390_INT_EXTERNAL_CALL,
.parm = vcpu->vcpu_id,
};
struct kvm_vcpu *dst_vcpu = NULL;
int rc;
if (cpu_addr < KVM_MAX_VCPUS)
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
rc = kvm_s390_inject_vcpu(dst_vcpu, &s390int);
if (!rc)
VCPU_EVENT(vcpu, 4, "sent sigp ext call to cpu %x", cpu_addr);
return rc ? rc : SIGP_CC_ORDER_CODE_ACCEPTED;
}
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 (li->action_bits & ACTION_STOP_ON_STOP) {
/* another SIGP STOP is pending */
rc = SIGP_CC_BUSY;
goto out;
}
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);
li->action_bits |= action;
atomic_set_mask(CPUSTAT_STOP_INT, li->cpuflags);
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_local_interrupt *li;
struct kvm_vcpu *dst_vcpu = NULL;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return SIGP_CC_NOT_OPERATIONAL;
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
li = &dst_vcpu->arch.local_int;
rc = __inject_sigp_stop(li, action);
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. */
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;
unsigned int i;
struct kvm_vcpu *v;
switch (parameter & 0xff) {
case 0:
rc = SIGP_CC_NOT_OPERATIONAL;
break;
case 1:
case 2:
kvm_for_each_vcpu(i, v, vcpu->kvm) {
v->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
kvm_clear_async_pf_completion_queue(v);
}
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_local_interrupt *li;
struct kvm_vcpu *dst_vcpu = NULL;
struct kvm_s390_interrupt_info *inti;
int rc;
if (cpu_addr < KVM_MAX_VCPUS)
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
li = &dst_vcpu->arch.local_int;
/*
* Make sure the new value is valid memory. We only need to check the
* first page, since address is 8k aligned and memory pieces are always
* at least 1MB aligned and have at least a size of 1MB.
*/
address &= 0x7fffe000u;
if (kvm_is_error_gpa(vcpu->kvm, address)) {
*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_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);
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)
{
struct kvm_s390_local_interrupt *li;
struct kvm_vcpu *dst_vcpu = NULL;
int rc;
if (cpu_addr >= KVM_MAX_VCPUS)
return SIGP_CC_NOT_OPERATIONAL;
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
li = &dst_vcpu->arch.local_int;
if (atomic_read(li->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;
}
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_local_interrupt *li;
int rc = SIGP_CC_ORDER_CODE_ACCEPTED;
struct kvm_vcpu *dst_vcpu = NULL;
if (cpu_addr >= KVM_MAX_VCPUS)
return SIGP_CC_NOT_OPERATIONAL;
dst_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
if (!dst_vcpu)
return SIGP_CC_NOT_OPERATIONAL;
li = &dst_vcpu->arch.local_int;
spin_lock_bh(&li->lock);
if (li->action_bits & ACTION_STOP_ON_STOP)
rc = SIGP_CC_BUSY;
spin_unlock_bh(&li->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_START:
rc = sigp_check_callable(vcpu, cpu_addr);
if (rc == SIGP_CC_ORDER_CODE_ACCEPTED)
rc = -EOPNOTSUPP; /* Handle START in user space */
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;
}
/*
* Handle SIGP partial execution interception.
*
* This interception will occur at the source cpu when a source cpu sends an
* external call to a target cpu and the target cpu has the WAIT bit set in
* its cpuflags. Interception will occurr after the interrupt indicator bits at
* the target cpu have been set. All error cases will lead to instruction
* interception, therefore nothing is to be checked or prepared.
*/
int kvm_s390_handle_sigp_pei(struct kvm_vcpu *vcpu)
{
int r3 = vcpu->arch.sie_block->ipa & 0x000f;
u16 cpu_addr = vcpu->run->s.regs.gprs[r3];
struct kvm_vcpu *dest_vcpu;
u8 order_code = kvm_s390_get_base_disp_rs(vcpu);
trace_kvm_s390_handle_sigp_pei(vcpu, order_code, cpu_addr);
if (order_code == SIGP_EXTERNAL_CALL) {
dest_vcpu = kvm_get_vcpu(vcpu->kvm, cpu_addr);
BUG_ON(dest_vcpu == NULL);
spin_lock_bh(&dest_vcpu->arch.local_int.lock);
if (waitqueue_active(&dest_vcpu->wq))
wake_up_interruptible(&dest_vcpu->wq);
dest_vcpu->preempted = true;
spin_unlock_bh(&dest_vcpu->arch.local_int.lock);
kvm_s390_set_psw_cc(vcpu, SIGP_CC_ORDER_CODE_ACCEPTED);
return 0;
}
return -EOPNOTSUPP;
}
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