qemu/hw/intc/s390_flic.c
Dominik Dingel 819bd3091e s390x/async_pf: Check for apf extension and enable pfault
S390 can also use async page faults, to enhance guest scheduling.
In case of live migration we want to disable the feature and let
all pending request finish.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
2014-02-27 09:51:25 +01:00

323 lines
8.2 KiB
C

/*
* QEMU S390x KVM floating interrupt controller (flic)
*
* Copyright 2014 IBM Corp.
* Author(s): Jens Freimann <jfrei@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or (at
* your option) any later version. See the COPYING file in the top-level
* directory.
*/
#include <sys/ioctl.h>
#include "qemu/error-report.h"
#include "hw/sysbus.h"
#include "sysemu/kvm.h"
#include "migration/qemu-file.h"
#include "hw/s390x/s390_flic.h"
#include "trace.h"
#define FLIC_SAVE_INITIAL_SIZE getpagesize()
#define FLIC_FAILED (-1UL)
#define FLIC_SAVEVM_VERSION 1
void s390_flic_init(void)
{
DeviceState *dev;
int r;
if (kvm_enabled()) {
dev = qdev_create(NULL, "s390-flic");
object_property_add_child(qdev_get_machine(), "s390-flic",
OBJECT(dev), NULL);
r = qdev_init(dev);
if (r) {
error_report("flic: couldn't create qdev");
}
}
}
/**
* flic_get_all_irqs - store all pending irqs in buffer
* @buf: pointer to buffer which is passed to kernel
* @len: length of buffer
* @flic: pointer to flic device state
*
* Returns: -ENOMEM if buffer is too small,
* -EINVAL if attr.group is invalid,
* -EFAULT if copying to userspace failed,
* on success return number of stored interrupts
*/
static int flic_get_all_irqs(KVMS390FLICState *flic,
void *buf, int len)
{
struct kvm_device_attr attr = {
.group = KVM_DEV_FLIC_GET_ALL_IRQS,
.addr = (uint64_t) buf,
.attr = len,
};
int rc;
rc = ioctl(flic->fd, KVM_GET_DEVICE_ATTR, &attr);
return rc == -1 ? -errno : rc;
}
static void flic_enable_pfault(KVMS390FLICState *flic)
{
struct kvm_device_attr attr = {
.group = KVM_DEV_FLIC_APF_ENABLE,
};
int rc;
rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
if (rc) {
fprintf(stderr, "flic: couldn't enable pfault\n");
}
}
static void flic_disable_wait_pfault(KVMS390FLICState *flic)
{
struct kvm_device_attr attr = {
.group = KVM_DEV_FLIC_APF_DISABLE_WAIT,
};
int rc;
rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
if (rc) {
fprintf(stderr, "flic: couldn't disable pfault\n");
}
}
/** flic_enqueue_irqs - returns 0 on success
* @buf: pointer to buffer which is passed to kernel
* @len: length of buffer
* @flic: pointer to flic device state
*
* Returns: -EINVAL if attr.group is unknown
*/
static int flic_enqueue_irqs(void *buf, uint64_t len,
KVMS390FLICState *flic)
{
int rc;
struct kvm_device_attr attr = {
.group = KVM_DEV_FLIC_ENQUEUE,
.addr = (uint64_t) buf,
.attr = len,
};
rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
return rc ? -errno : 0;
}
/**
* __get_all_irqs - store all pending irqs in buffer
* @flic: pointer to flic device state
* @buf: pointer to pointer to a buffer
* @len: length of buffer
*
* Returns: return value of flic_get_all_irqs
* Note: Retry and increase buffer size until flic_get_all_irqs
* either returns a value >= 0 or a negative error code.
* -ENOMEM is an exception, which means the buffer is too small
* and we should try again. Other negative error codes can be
* -EFAULT and -EINVAL which we ignore at this point
*/
static int __get_all_irqs(KVMS390FLICState *flic,
void **buf, int len)
{
int r;
do {
/* returns -ENOMEM if buffer is too small and number
* of queued interrupts on success */
r = flic_get_all_irqs(flic, *buf, len);
if (r >= 0) {
break;
}
len *= 2;
*buf = g_try_realloc(*buf, len);
if (!buf) {
return -ENOMEM;
}
} while (r == -ENOMEM && len <= KVM_S390_FLIC_MAX_BUFFER);
return r;
}
/**
* kvm_flic_save - Save pending floating interrupts
* @f: QEMUFile containing migration state
* @opaque: pointer to flic device state
*
* Note: Pass buf and len to kernel. Start with one page and
* increase until buffer is sufficient or maxium size is
* reached
*/
static void kvm_flic_save(QEMUFile *f, void *opaque)
{
KVMS390FLICState *flic = opaque;
int len = FLIC_SAVE_INITIAL_SIZE;
void *buf;
int count;
flic_disable_wait_pfault((struct KVMS390FLICState *) opaque);
buf = g_try_malloc0(len);
if (!buf) {
/* Storing FLIC_FAILED into the count field here will cause the
* target system to fail when attempting to load irqs from the
* migration state */
error_report("flic: couldn't allocate memory");
qemu_put_be64(f, FLIC_FAILED);
return;
}
count = __get_all_irqs(flic, &buf, len);
if (count < 0) {
error_report("flic: couldn't retrieve irqs from kernel, rc %d",
count);
/* Storing FLIC_FAILED into the count field here will cause the
* target system to fail when attempting to load irqs from the
* migration state */
qemu_put_be64(f, FLIC_FAILED);
} else {
qemu_put_be64(f, count);
qemu_put_buffer(f, (uint8_t *) buf,
count * sizeof(struct kvm_s390_irq));
}
g_free(buf);
}
/**
* kvm_flic_load - Load pending floating interrupts
* @f: QEMUFile containing migration state
* @opaque: pointer to flic device state
* @version_id: version id for migration
*
* Returns: value of flic_enqueue_irqs, -EINVAL on error
* Note: Do nothing when no interrupts where stored
* in QEMUFile
*/
static int kvm_flic_load(QEMUFile *f, void *opaque, int version_id)
{
uint64_t len = 0;
uint64_t count = 0;
void *buf = NULL;
int r = 0;
if (version_id != FLIC_SAVEVM_VERSION) {
r = -EINVAL;
goto out;
}
flic_enable_pfault((struct KVMS390FLICState *) opaque);
count = qemu_get_be64(f);
len = count * sizeof(struct kvm_s390_irq);
if (count == FLIC_FAILED) {
r = -EINVAL;
goto out;
}
if (count == 0) {
r = 0;
goto out;
}
buf = g_try_malloc0(len);
if (!buf) {
r = -ENOMEM;
goto out;
}
if (qemu_get_buffer(f, (uint8_t *) buf, len) != len) {
r = -EINVAL;
goto out_free;
}
r = flic_enqueue_irqs(buf, len, (struct KVMS390FLICState *) opaque);
out_free:
g_free(buf);
out:
return r;
}
static void kvm_s390_flic_realize(DeviceState *dev, Error **errp)
{
KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
struct kvm_create_device cd = {0};
int ret;
flic_state->fd = -1;
if (!kvm_check_extension(kvm_state, KVM_CAP_DEVICE_CTRL)) {
trace_flic_no_device_api(errno);
return;
}
cd.type = KVM_DEV_TYPE_FLIC;
ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_DEVICE, &cd);
if (ret < 0) {
trace_flic_create_device(errno);
return;
}
flic_state->fd = cd.fd;
/* Register savevm handler for floating interrupts */
register_savevm(NULL, "s390-flic", 0, 1, kvm_flic_save,
kvm_flic_load, (void *) flic_state);
}
static void kvm_s390_flic_unrealize(DeviceState *dev, Error **errp)
{
KVMS390FLICState *flic_state = KVM_S390_FLIC(dev);
unregister_savevm(DEVICE(flic_state), "s390-flic", flic_state);
}
static void kvm_s390_flic_reset(DeviceState *dev)
{
KVMS390FLICState *flic = KVM_S390_FLIC(dev);
struct kvm_device_attr attr = {
.group = KVM_DEV_FLIC_CLEAR_IRQS,
};
int rc = 0;
if (flic->fd == -1) {
return;
}
flic_disable_wait_pfault(flic);
rc = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
if (rc) {
trace_flic_reset_failed(errno);
}
flic_enable_pfault(flic);
}
static void kvm_s390_flic_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
dc->realize = kvm_s390_flic_realize;
dc->unrealize = kvm_s390_flic_unrealize;
dc->reset = kvm_s390_flic_reset;
}
static const TypeInfo kvm_s390_flic_info = {
.name = TYPE_KVM_S390_FLIC,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(KVMS390FLICState),
.class_init = kvm_s390_flic_class_init,
};
static void kvm_s390_flic_register_types(void)
{
type_register_static(&kvm_s390_flic_info);
}
type_init(kvm_s390_flic_register_types)