qemu/hw/input/virtio-input.c
Paolo Bonzini 51b19ebe43 virtio: move allocation to virtqueue_pop/vring_pop
The return code of virtqueue_pop/vring_pop is unused except to check for
errors or 0.  We can thus easily move allocation inside the functions
and just return a pointer to the VirtQueueElement.

The advantage is that we will be able to allocate only the space that
is needed for the actual size of the s/g list instead of the full
VIRTQUEUE_MAX_SIZE items.  Currently VirtQueueElement takes about 48K
of memory, and this kind of allocation puts a lot of stress on malloc.
By cutting the size by two or three orders of magnitude, malloc can
use much more efficient algorithms.

The patch is pretty large, but changes to each device are testable
more or less independently.  Splitting it would mostly add churn.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2016-02-06 20:39:07 +02:00

303 lines
8.6 KiB
C

/*
* 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 "qemu/osdep.h"
#include "qemu/iov.h"
#include "hw/qdev.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-input.h"
#include "standard-headers/linux/input.h"
/* ----------------------------------------------------------------- */
void virtio_input_send(VirtIOInput *vinput, virtio_input_event *event)
{
VirtQueueElement *elem;
unsigned have, need;
int i, len;
if (!vinput->active) {
return;
}
/* queue up events ... */
if (vinput->qindex == vinput->qsize) {
vinput->qsize++;
vinput->queue = realloc(vinput->queue, vinput->qsize *
sizeof(virtio_input_event));
}
vinput->queue[vinput->qindex++] = *event;
/* ... until we see a report sync ... */
if (event->type != cpu_to_le16(EV_SYN) ||
event->code != cpu_to_le16(SYN_REPORT)) {
return;
}
/* ... then check available space ... */
need = sizeof(virtio_input_event) * vinput->qindex;
virtqueue_get_avail_bytes(vinput->evt, &have, NULL, need, 0);
if (have < need) {
vinput->qindex = 0;
fprintf(stderr, "%s: ENOSPC in vq, dropping events\n", __func__);
return;
}
/* ... and finally pass them to the guest */
for (i = 0; i < vinput->qindex; i++) {
elem = virtqueue_pop(vinput->evt, sizeof(VirtQueueElement));
if (!elem) {
/* should not happen, we've checked for space beforehand */
fprintf(stderr, "%s: Huh? No vq elem available ...\n", __func__);
return;
}
len = iov_from_buf(elem->in_sg, elem->in_num,
0, vinput->queue+i, sizeof(virtio_input_event));
virtqueue_push(vinput->evt, elem, len);
g_free(elem);
}
virtio_notify(VIRTIO_DEVICE(vinput), vinput->evt);
vinput->qindex = 0;
}
static void virtio_input_handle_evt(VirtIODevice *vdev, VirtQueue *vq)
{
/* nothing */
}
static void virtio_input_handle_sts(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
VirtIOInput *vinput = VIRTIO_INPUT(vdev);
virtio_input_event event;
VirtQueueElement *elem;
int len;
for (;;) {
elem = virtqueue_pop(vinput->sts, sizeof(VirtQueueElement));
if (!elem) {
break;
}
memset(&event, 0, sizeof(event));
len = iov_to_buf(elem->out_sg, elem->out_num,
0, &event, sizeof(event));
if (vic->handle_status) {
vic->handle_status(vinput, &event);
}
virtqueue_push(vinput->sts, elem, len);
g_free(elem);
}
virtio_notify(vdev, vinput->sts);
}
static virtio_input_config *virtio_input_find_config(VirtIOInput *vinput,
uint8_t select,
uint8_t subsel)
{
VirtIOInputConfig *cfg;
QTAILQ_FOREACH(cfg, &vinput->cfg_list, node) {
if (select == cfg->config.select &&
subsel == cfg->config.subsel) {
return &cfg->config;
}
}
return NULL;
}
void virtio_input_add_config(VirtIOInput *vinput,
virtio_input_config *config)
{
VirtIOInputConfig *cfg;
if (virtio_input_find_config(vinput, config->select, config->subsel)) {
/* should not happen */
fprintf(stderr, "%s: duplicate config: %d/%d\n",
__func__, config->select, config->subsel);
abort();
}
cfg = g_new0(VirtIOInputConfig, 1);
cfg->config = *config;
QTAILQ_INSERT_TAIL(&vinput->cfg_list, cfg, node);
}
void virtio_input_init_config(VirtIOInput *vinput,
virtio_input_config *config)
{
int i = 0;
QTAILQ_INIT(&vinput->cfg_list);
while (config[i].select) {
virtio_input_add_config(vinput, config + i);
i++;
}
}
void virtio_input_idstr_config(VirtIOInput *vinput,
uint8_t select, const char *string)
{
virtio_input_config id;
if (!string) {
return;
}
memset(&id, 0, sizeof(id));
id.select = select;
id.size = snprintf(id.u.string, sizeof(id.u.string), "%s", string);
virtio_input_add_config(vinput, &id);
}
static void virtio_input_get_config(VirtIODevice *vdev, uint8_t *config_data)
{
VirtIOInput *vinput = VIRTIO_INPUT(vdev);
virtio_input_config *config;
config = virtio_input_find_config(vinput, vinput->cfg_select,
vinput->cfg_subsel);
if (config) {
memcpy(config_data, config, vinput->cfg_size);
} else {
memset(config_data, 0, vinput->cfg_size);
}
}
static void virtio_input_set_config(VirtIODevice *vdev,
const uint8_t *config_data)
{
VirtIOInput *vinput = VIRTIO_INPUT(vdev);
virtio_input_config *config = (virtio_input_config *)config_data;
vinput->cfg_select = config->select;
vinput->cfg_subsel = config->subsel;
virtio_notify_config(vdev);
}
static uint64_t virtio_input_get_features(VirtIODevice *vdev, uint64_t f,
Error **errp)
{
return f;
}
static void virtio_input_set_status(VirtIODevice *vdev, uint8_t val)
{
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
VirtIOInput *vinput = VIRTIO_INPUT(vdev);
if (val & VIRTIO_CONFIG_S_DRIVER_OK) {
if (!vinput->active) {
vinput->active = true;
if (vic->change_active) {
vic->change_active(vinput);
}
}
}
}
static void virtio_input_reset(VirtIODevice *vdev)
{
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
VirtIOInput *vinput = VIRTIO_INPUT(vdev);
if (vinput->active) {
vinput->active = false;
if (vic->change_active) {
vic->change_active(vinput);
}
}
}
static void virtio_input_device_realize(DeviceState *dev, Error **errp)
{
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(dev);
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOInput *vinput = VIRTIO_INPUT(dev);
VirtIOInputConfig *cfg;
Error *local_err = NULL;
if (vic->realize) {
vic->realize(dev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
}
virtio_input_idstr_config(vinput, VIRTIO_INPUT_CFG_ID_SERIAL,
vinput->serial);
QTAILQ_FOREACH(cfg, &vinput->cfg_list, node) {
if (vinput->cfg_size < cfg->config.size) {
vinput->cfg_size = cfg->config.size;
}
}
vinput->cfg_size += 8;
assert(vinput->cfg_size <= sizeof(virtio_input_config));
virtio_init(vdev, "virtio-input", VIRTIO_ID_INPUT,
vinput->cfg_size);
vinput->evt = virtio_add_queue(vdev, 64, virtio_input_handle_evt);
vinput->sts = virtio_add_queue(vdev, 64, virtio_input_handle_sts);
}
static void virtio_input_device_unrealize(DeviceState *dev, Error **errp)
{
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(dev);
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
Error *local_err = NULL;
if (vic->unrealize) {
vic->unrealize(dev, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
}
virtio_cleanup(vdev);
}
static Property virtio_input_properties[] = {
DEFINE_PROP_STRING("serial", VirtIOInput, serial),
DEFINE_PROP_END_OF_LIST(),
};
static void virtio_input_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
dc->props = virtio_input_properties;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
vdc->realize = virtio_input_device_realize;
vdc->unrealize = virtio_input_device_unrealize;
vdc->get_config = virtio_input_get_config;
vdc->set_config = virtio_input_set_config;
vdc->get_features = virtio_input_get_features;
vdc->set_status = virtio_input_set_status;
vdc->reset = virtio_input_reset;
}
static const TypeInfo virtio_input_info = {
.name = TYPE_VIRTIO_INPUT,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VirtIOInput),
.class_size = sizeof(VirtIOInputClass),
.class_init = virtio_input_class_init,
.abstract = true,
};
/* ----------------------------------------------------------------- */
static void virtio_register_types(void)
{
type_register_static(&virtio_input_info);
}
type_init(virtio_register_types)