event_notifier_init() can fail in real life, for example when there are not enough open file handles available (EMFILE) when using a lot of devices. So instead of leaving the average user with a cryptic error number only, print out a proper error message with strerror() instead, so that the user has a better way to figure out what is going on and that using "ulimit -n" might help here for example. Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
310 lines
8.9 KiB
C
310 lines
8.9 KiB
C
/*
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* VirtioBus
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*
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* Copyright (C) 2012 : GreenSocs Ltd
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* http://www.greensocs.com/ , email: info@greensocs.com
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*
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* Developed by :
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* Frederic Konrad <fred.konrad@greensocs.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "qemu/osdep.h"
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#include "hw/hw.h"
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#include "qemu/error-report.h"
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#include "hw/qdev.h"
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#include "hw/virtio/virtio-bus.h"
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#include "hw/virtio/virtio.h"
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/* #define DEBUG_VIRTIO_BUS */
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#ifdef DEBUG_VIRTIO_BUS
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#define DPRINTF(fmt, ...) \
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do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
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#else
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#define DPRINTF(fmt, ...) do { } while (0)
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#endif
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/* A VirtIODevice is being plugged */
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void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
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{
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DeviceState *qdev = DEVICE(vdev);
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BusState *qbus = BUS(qdev_get_parent_bus(qdev));
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VirtioBusState *bus = VIRTIO_BUS(qbus);
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VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
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VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
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DPRINTF("%s: plug device.\n", qbus->name);
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if (klass->device_plugged != NULL) {
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klass->device_plugged(qbus->parent, errp);
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}
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/* Get the features of the plugged device. */
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assert(vdc->get_features != NULL);
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vdev->host_features = vdc->get_features(vdev, vdev->host_features,
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errp);
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if (klass->post_plugged != NULL) {
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klass->post_plugged(qbus->parent, errp);
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}
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}
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/* Reset the virtio_bus */
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void virtio_bus_reset(VirtioBusState *bus)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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DPRINTF("%s: reset device.\n", BUS(bus)->name);
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if (vdev != NULL) {
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virtio_reset(vdev);
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}
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}
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/* A VirtIODevice is being unplugged */
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void virtio_bus_device_unplugged(VirtIODevice *vdev)
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{
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DeviceState *qdev = DEVICE(vdev);
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BusState *qbus = BUS(qdev_get_parent_bus(qdev));
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VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
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DPRINTF("%s: remove device.\n", qbus->name);
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if (vdev != NULL) {
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if (klass->device_unplugged != NULL) {
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klass->device_unplugged(qbus->parent);
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}
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}
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}
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/* Get the device id of the plugged device. */
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uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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assert(vdev != NULL);
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return vdev->device_id;
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}
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/* Get the config_len field of the plugged device. */
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size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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assert(vdev != NULL);
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return vdev->config_len;
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}
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/* Get bad features of the plugged device. */
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uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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VirtioDeviceClass *k;
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assert(vdev != NULL);
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k = VIRTIO_DEVICE_GET_CLASS(vdev);
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if (k->bad_features != NULL) {
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return k->bad_features(vdev);
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} else {
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return 0;
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}
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}
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/* Get config of the plugged device. */
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void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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VirtioDeviceClass *k;
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assert(vdev != NULL);
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k = VIRTIO_DEVICE_GET_CLASS(vdev);
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if (k->get_config != NULL) {
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k->get_config(vdev, config);
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}
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}
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/* Set config of the plugged device. */
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void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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VirtioDeviceClass *k;
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assert(vdev != NULL);
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k = VIRTIO_DEVICE_GET_CLASS(vdev);
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if (k->set_config != NULL) {
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k->set_config(vdev, config);
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}
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}
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/*
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* This function handles both assigning the ioeventfd handler and
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* registering it with the kernel.
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* assign: register/deregister ioeventfd with the kernel
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* set_handler: use the generic ioeventfd handler
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*/
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static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
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int n, bool assign, bool set_handler)
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{
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VirtIODevice *vdev = virtio_bus_get_device(bus);
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
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VirtQueue *vq = virtio_get_queue(vdev, n);
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EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
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int r = 0;
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if (assign) {
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r = event_notifier_init(notifier, 1);
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if (r < 0) {
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error_report("%s: unable to init event notifier: %s (%d)",
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__func__, strerror(-r), r);
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return r;
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}
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virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
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r = k->ioeventfd_assign(proxy, notifier, n, assign);
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if (r < 0) {
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error_report("%s: unable to assign ioeventfd: %d", __func__, r);
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virtio_queue_set_host_notifier_fd_handler(vq, false, false);
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event_notifier_cleanup(notifier);
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return r;
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}
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} else {
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k->ioeventfd_assign(proxy, notifier, n, assign);
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virtio_queue_set_host_notifier_fd_handler(vq, false, false);
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event_notifier_cleanup(notifier);
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}
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return r;
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}
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void virtio_bus_start_ioeventfd(VirtioBusState *bus)
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{
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
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DeviceState *proxy = DEVICE(BUS(bus)->parent);
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VirtIODevice *vdev;
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int n, r;
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if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) {
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return;
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}
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if (k->ioeventfd_disabled(proxy)) {
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return;
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}
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vdev = virtio_bus_get_device(bus);
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for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
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if (!virtio_queue_get_num(vdev, n)) {
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continue;
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}
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r = set_host_notifier_internal(proxy, bus, n, true, true);
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if (r < 0) {
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goto assign_error;
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}
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}
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k->ioeventfd_set_started(proxy, true, false);
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return;
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assign_error:
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while (--n >= 0) {
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if (!virtio_queue_get_num(vdev, n)) {
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continue;
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}
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r = set_host_notifier_internal(proxy, bus, n, false, false);
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assert(r >= 0);
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}
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k->ioeventfd_set_started(proxy, false, true);
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error_report("%s: failed. Fallback to userspace (slower).", __func__);
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}
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void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
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{
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
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DeviceState *proxy = DEVICE(BUS(bus)->parent);
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VirtIODevice *vdev;
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int n, r;
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if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) {
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return;
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}
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vdev = virtio_bus_get_device(bus);
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for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
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if (!virtio_queue_get_num(vdev, n)) {
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continue;
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}
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r = set_host_notifier_internal(proxy, bus, n, false, false);
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assert(r >= 0);
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}
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k->ioeventfd_set_started(proxy, false, false);
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}
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/*
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* This function switches from/to the generic ioeventfd handler.
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* assign==false means 'use generic ioeventfd handler'.
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*/
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int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
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{
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
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DeviceState *proxy = DEVICE(BUS(bus)->parent);
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if (!k->ioeventfd_started) {
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return -ENOSYS;
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}
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k->ioeventfd_set_disabled(proxy, assign);
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if (assign) {
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/*
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* Stop using the generic ioeventfd, we are doing eventfd handling
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* ourselves below
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*
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* FIXME: We should just switch the handler and not deassign the
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* ioeventfd.
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* Otherwise, there's a window where we don't have an
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* ioeventfd and we may end up with a notification where
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* we don't expect one.
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*/
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virtio_bus_stop_ioeventfd(bus);
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}
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return set_host_notifier_internal(proxy, bus, n, assign, false);
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}
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static char *virtio_bus_get_dev_path(DeviceState *dev)
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{
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BusState *bus = qdev_get_parent_bus(dev);
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DeviceState *proxy = DEVICE(bus->parent);
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return qdev_get_dev_path(proxy);
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}
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static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
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{
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return NULL;
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}
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static void virtio_bus_class_init(ObjectClass *klass, void *data)
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{
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BusClass *bus_class = BUS_CLASS(klass);
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bus_class->get_dev_path = virtio_bus_get_dev_path;
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bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
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}
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static const TypeInfo virtio_bus_info = {
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.name = TYPE_VIRTIO_BUS,
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.parent = TYPE_BUS,
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.instance_size = sizeof(VirtioBusState),
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.abstract = true,
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.class_size = sizeof(VirtioBusClass),
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.class_init = virtio_bus_class_init
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};
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static void virtio_register_types(void)
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{
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type_register_static(&virtio_bus_info);
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}
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type_init(virtio_register_types)
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