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vhost-vsock: add vhost-vsock-common abstraction
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This patch prepares the introduction of vhost-user-vsock, moving
the common code usable for both vhost-vsock and vhost-user-vsock
devices, in the new vhost-vsock-common parent class.

While moving the code, fixed checkpatch warnings about block comments.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20200522122512.87413-2-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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@stefano-garzarella @mstsirkin
stefano-garzarella authored and mstsirkin committed Jun 12, 2020
1 parent 0082398 commit c6136ec
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Showing 5 changed files with 350 additions and 251 deletions.
2 changes: 1 addition & 1 deletion hw/virtio/Makefile.objs
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Expand Up @@ -17,7 +17,7 @@ obj-$(CONFIG_VIRTIO_PMEM) += virtio-pmem.o
common-obj-$(call land,$(CONFIG_VIRTIO_PMEM),$(CONFIG_VIRTIO_PCI)) += virtio-pmem-pci.o
obj-$(call land,$(CONFIG_VHOST_USER_FS),$(CONFIG_VIRTIO_PCI)) += vhost-user-fs-pci.o
obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock.o
obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-common.o vhost-vsock.o

ifeq ($(CONFIG_VIRTIO_PCI),y)
obj-$(CONFIG_VHOST_VSOCK) += vhost-vsock-pci.o
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258 changes: 258 additions & 0 deletions hw/virtio/vhost-vsock-common.c
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@@ -0,0 +1,258 @@
/*
* Parent class for vhost-vsock devices
*
* Copyright 2015-2020 Red Hat, Inc.
*
* 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 "standard-headers/linux/virtio_vsock.h"
#include "qapi/error.h"
#include "hw/virtio/virtio-access.h"
#include "qemu/error-report.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/vhost-vsock.h"
#include "qemu/iov.h"
#include "monitor/monitor.h"

int vhost_vsock_common_start(VirtIODevice *vdev)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret;
int i;

if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
return -ENOSYS;
}

ret = vhost_dev_enable_notifiers(&vvc->vhost_dev, vdev);
if (ret < 0) {
error_report("Error enabling host notifiers: %d", -ret);
return ret;
}

ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, true);
if (ret < 0) {
error_report("Error binding guest notifier: %d", -ret);
goto err_host_notifiers;
}

vvc->vhost_dev.acked_features = vdev->guest_features;
ret = vhost_dev_start(&vvc->vhost_dev, vdev);
if (ret < 0) {
error_report("Error starting vhost: %d", -ret);
goto err_guest_notifiers;
}

/*
* guest_notifier_mask/pending not used yet, so just unmask
* everything here. virtio-pci will do the right thing by
* enabling/disabling irqfd.
*/
for (i = 0; i < vvc->vhost_dev.nvqs; i++) {
vhost_virtqueue_mask(&vvc->vhost_dev, vdev, i, false);
}

return 0;

err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&vvc->vhost_dev, vdev);
return ret;
}

void vhost_vsock_common_stop(VirtIODevice *vdev)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret;

if (!k->set_guest_notifiers) {
return;
}

vhost_dev_stop(&vvc->vhost_dev, vdev);

ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
return;
}

vhost_dev_disable_notifiers(&vvc->vhost_dev, vdev);
}


static void vhost_vsock_common_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
/* Do nothing */
}

static void vhost_vsock_common_guest_notifier_mask(VirtIODevice *vdev, int idx,
bool mask)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);

vhost_virtqueue_mask(&vvc->vhost_dev, vdev, idx, mask);
}

static bool vhost_vsock_common_guest_notifier_pending(VirtIODevice *vdev,
int idx)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);

return vhost_virtqueue_pending(&vvc->vhost_dev, idx);
}

static void vhost_vsock_common_send_transport_reset(VHostVSockCommon *vvc)
{
VirtQueueElement *elem;
VirtQueue *vq = vvc->event_vq;
struct virtio_vsock_event event = {
.id = cpu_to_le32(VIRTIO_VSOCK_EVENT_TRANSPORT_RESET),
};

elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
if (!elem) {
error_report("vhost-vsock missed transport reset event");
return;
}

if (elem->out_num) {
error_report("invalid vhost-vsock event virtqueue element with "
"out buffers");
goto out;
}

if (iov_from_buf(elem->in_sg, elem->in_num, 0,
&event, sizeof(event)) != sizeof(event)) {
error_report("vhost-vsock event virtqueue element is too short");
goto out;
}

virtqueue_push(vq, elem, sizeof(event));
virtio_notify(VIRTIO_DEVICE(vvc), vq);

out:
g_free(elem);
}

static void vhost_vsock_common_post_load_timer_cleanup(VHostVSockCommon *vvc)
{
if (!vvc->post_load_timer) {
return;
}

timer_del(vvc->post_load_timer);
timer_free(vvc->post_load_timer);
vvc->post_load_timer = NULL;
}

static void vhost_vsock_common_post_load_timer_cb(void *opaque)
{
VHostVSockCommon *vvc = opaque;

vhost_vsock_common_post_load_timer_cleanup(vvc);
vhost_vsock_common_send_transport_reset(vvc);
}

int vhost_vsock_common_pre_save(void *opaque)
{
VHostVSockCommon *vvc = opaque;

/*
* At this point, backend must be stopped, otherwise
* it might keep writing to memory.
*/
assert(!vvc->vhost_dev.started);

return 0;
}

int vhost_vsock_common_post_load(void *opaque, int version_id)
{
VHostVSockCommon *vvc = opaque;
VirtIODevice *vdev = VIRTIO_DEVICE(vvc);

if (virtio_queue_get_addr(vdev, 2)) {
/*
* Defer transport reset event to a vm clock timer so that virtqueue
* changes happen after migration has completed.
*/
assert(!vvc->post_load_timer);
vvc->post_load_timer =
timer_new_ns(QEMU_CLOCK_VIRTUAL,
vhost_vsock_common_post_load_timer_cb,
vvc);
timer_mod(vvc->post_load_timer, 1);
}
return 0;
}

void vhost_vsock_common_realize(VirtIODevice *vdev, const char *name)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);

virtio_init(vdev, name, VIRTIO_ID_VSOCK,
sizeof(struct virtio_vsock_config));

/* Receive and transmit queues belong to vhost */
vvc->recv_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
vhost_vsock_common_handle_output);
vvc->trans_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
vhost_vsock_common_handle_output);

/* The event queue belongs to QEMU */
vvc->event_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
vhost_vsock_common_handle_output);

vvc->vhost_dev.nvqs = ARRAY_SIZE(vvc->vhost_vqs);
vvc->vhost_dev.vqs = vvc->vhost_vqs;

vvc->post_load_timer = NULL;
}

void vhost_vsock_common_unrealize(VirtIODevice *vdev)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);

vhost_vsock_common_post_load_timer_cleanup(vvc);

virtio_delete_queue(vvc->recv_vq);
virtio_delete_queue(vvc->trans_vq);
virtio_delete_queue(vvc->event_vq);
virtio_cleanup(vdev);
}

static void vhost_vsock_common_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);

set_bit(DEVICE_CATEGORY_MISC, dc->categories);
vdc->guest_notifier_mask = vhost_vsock_common_guest_notifier_mask;
vdc->guest_notifier_pending = vhost_vsock_common_guest_notifier_pending;
}

static const TypeInfo vhost_vsock_common_info = {
.name = TYPE_VHOST_VSOCK_COMMON,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VHostVSockCommon),
.class_init = vhost_vsock_common_class_init,
.abstract = true,
};

static void vhost_vsock_common_register_types(void)
{
type_register_static(&vhost_vsock_common_info);
}

type_init(vhost_vsock_common_register_types)

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