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xemu/hw/input/virtio-input.c
Ladi Prosek 57094547df virtio-input: fix eventq batching 
virtio_input_send buffers input events until it sees a SYNC. Then it
either sends or drops the entire batch, depending on whether eventq
has enough space available. The case to avoid here is partial sends
where only part of the batch would get to the guest.

Using virtqueue_get_avail_bytes to check the state of eventq was not
correct. The queue may have a smaller number of larger buffers
available so bytes may be enough but the batch would still not be
possible to send, leading to the "Huh?  No vq elem available" error.

Instead of checking available bytes, this patch optimistically pops
buffers from the queue and puts them back in case it runs out of
space and the batch needs to be dropped.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Message-id: 1490365490-4854-3-git-send-email-lprosek@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2017-03-27 12:14:45 +02:00

344 lines
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/*
* 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 "qapi/error.h"
#include "qemu/iov.h"
#include "trace.h"
#include "hw/qdev.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-input.h"
#include "standard-headers/linux/input.h"
#define VIRTIO_INPUT_VM_VERSION 1
/* ----------------------------------------------------------------- */
void virtio_input_send(VirtIOInput *vinput, virtio_input_event *event)
{
VirtQueueElement *elem;
int i, len;
if (!vinput->active) {
return;
}
/* queue up events ... */
if (vinput->qindex == vinput->qsize) {
vinput->qsize++;
vinput->queue = g_realloc(vinput->queue, vinput->qsize *
sizeof(vinput->queue[0]));
}
vinput->queue[vinput->qindex++].event = *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 ... */
for (i = 0; i < vinput->qindex; i++) {
elem = virtqueue_pop(vinput->evt, sizeof(VirtQueueElement));
if (!elem) {
while (--i >= 0) {
virtqueue_unpop(vinput->evt, vinput->queue[i].elem, 0);
}
vinput->qindex = 0;
trace_virtio_input_queue_full();
return;
}
vinput->queue[i].elem = elem;
}
/* ... and finally pass them to the guest */
for (i = 0; i < vinput->qindex; i++) {
elem = vinput->queue[i].elem;
len = iov_from_buf(elem->in_sg, elem->in_num,
0, &vinput->queue[i].event, 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);
}
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 int virtio_input_post_load(void *opaque, int version_id)
{
VirtIOInput *vinput = opaque;
VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vinput);
VirtIODevice *vdev = VIRTIO_DEVICE(vinput);
vinput->active = vdev->status & VIRTIO_CONFIG_S_DRIVER_OK;
if (vic->change_active) {
vic->change_active(vinput);
}
return 0;
}
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_finalize(Object *obj)
{
VirtIOInput *vinput = VIRTIO_INPUT(obj);
VirtIOInputConfig *cfg, *next;
QTAILQ_FOREACH_SAFE(cfg, &vinput->cfg_list, node, next) {
QTAILQ_REMOVE(&vinput->cfg_list, cfg, node);
g_free(cfg);
}
g_free(vinput->queue);
}
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 const VMStateDescription vmstate_virtio_input = {
.name = "virtio-input",
.minimum_version_id = VIRTIO_INPUT_VM_VERSION,
.version_id = VIRTIO_INPUT_VM_VERSION,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
.post_load = virtio_input_post_load,
};
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;
dc->vmsd = &vmstate_virtio_input;
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,
.instance_finalize = virtio_input_finalize,
};
/* ----------------------------------------------------------------- */
static void virtio_register_types(void)
{
type_register_static(&virtio_input_info);
}
type_init(virtio_register_types)
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