qemu-patch-raspberry4/hw/block/vhost-user-blk.c
Dima Stepanov f5b22d06fb vhost: recheck dev state in the vhost_migration_log routine
vhost-user devices can get a disconnect in the middle of the VHOST-USER
handshake on the migration start. If disconnect event happened right
before sending next VHOST-USER command, then the vhost_dev_set_log()
call in the vhost_migration_log() function will return error. This error
will lead to the assert() and close the QEMU migration source process.
For the vhost-user devices the disconnect event should not break the
migration process, because:
  - the device will be in the stopped state, so it will not be changed
    during migration
  - if reconnect will be made the migration log will be reinitialized as
    part of reconnect/init process:
    #0  vhost_log_global_start (listener=0x563989cf7be0)
    at hw/virtio/vhost.c:920
    #1  0x000056398603d8bc in listener_add_address_space (listener=0x563989cf7be0,
        as=0x563986ea4340 <address_space_memory>)
    at softmmu/memory.c:2664
    #2  0x000056398603dd30 in memory_listener_register (listener=0x563989cf7be0,
        as=0x563986ea4340 <address_space_memory>)
    at softmmu/memory.c:2740
    #3  0x0000563985fd6956 in vhost_dev_init (hdev=0x563989cf7bd8,
        opaque=0x563989cf7e30, backend_type=VHOST_BACKEND_TYPE_USER,
        busyloop_timeout=0)
    at hw/virtio/vhost.c:1385
    #4  0x0000563985f7d0b8 in vhost_user_blk_connect (dev=0x563989cf7990)
    at hw/block/vhost-user-blk.c:315
    #5  0x0000563985f7d3f6 in vhost_user_blk_event (opaque=0x563989cf7990,
        event=CHR_EVENT_OPENED)
    at hw/block/vhost-user-blk.c:379
Update the vhost-user-blk device with the internal started_vu field which
will be used for initialization (vhost_user_blk_start) and clean up
(vhost_user_blk_stop). This additional flag in the VhostUserBlk structure
will be used to track whether the device really needs to be stopped and
cleaned up on a vhost-user level.
The disconnect event will set the overall VHOST device (not vhost-user) to
the stopped state, so it can be used by the general vhost_migration_log
routine.
Such approach could be propogated to the other vhost-user devices, but
better idea is just to make the same connect/disconnect code for all the
vhost-user devices.

This migration issue was slightly discussed earlier:
  - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg01509.html
  - https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg05241.html

Signed-off-by: Dima Stepanov <dimastep@yandex-team.ru>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <9fbfba06791a87813fcee3e2315f0b904cc6789a.1599813294.git.dimastep@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-09-29 02:14:29 -04:00

588 lines
16 KiB
C

/*
* vhost-user-blk host device
*
* Copyright(C) 2017 Intel Corporation.
*
* Authors:
* Changpeng Liu <changpeng.liu@intel.com>
*
* Largely based on the "vhost-user-scsi.c" and "vhost-scsi.c" implemented by:
* Felipe Franciosi <felipe@nutanix.com>
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Nicholas Bellinger <nab@risingtidesystems.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/cutils.h"
#include "hw/qdev-core.h"
#include "hw/qdev-properties.h"
#include "hw/virtio/vhost.h"
#include "hw/virtio/vhost-user-blk.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/virtio-access.h"
#include "sysemu/sysemu.h"
#include "sysemu/runstate.h"
static const int user_feature_bits[] = {
VIRTIO_BLK_F_SIZE_MAX,
VIRTIO_BLK_F_SEG_MAX,
VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_BLK_SIZE,
VIRTIO_BLK_F_TOPOLOGY,
VIRTIO_BLK_F_MQ,
VIRTIO_BLK_F_RO,
VIRTIO_BLK_F_FLUSH,
VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_DISCARD,
VIRTIO_BLK_F_WRITE_ZEROES,
VIRTIO_F_VERSION_1,
VIRTIO_RING_F_INDIRECT_DESC,
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_F_NOTIFY_ON_EMPTY,
VHOST_INVALID_FEATURE_BIT
};
static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t *config)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
memcpy(config, &s->blkcfg, sizeof(struct virtio_blk_config));
}
static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
struct virtio_blk_config *blkcfg = (struct virtio_blk_config *)config;
int ret;
if (blkcfg->wce == s->blkcfg.wce) {
return;
}
ret = vhost_dev_set_config(&s->dev, &blkcfg->wce,
offsetof(struct virtio_blk_config, wce),
sizeof(blkcfg->wce),
VHOST_SET_CONFIG_TYPE_MASTER);
if (ret) {
error_report("set device config space failed");
return;
}
s->blkcfg.wce = blkcfg->wce;
}
static int vhost_user_blk_handle_config_change(struct vhost_dev *dev)
{
int ret;
struct virtio_blk_config blkcfg;
VHostUserBlk *s = VHOST_USER_BLK(dev->vdev);
ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg,
sizeof(struct virtio_blk_config));
if (ret < 0) {
error_report("get config space failed");
return -1;
}
/* valid for resize only */
if (blkcfg.capacity != s->blkcfg.capacity) {
s->blkcfg.capacity = blkcfg.capacity;
memcpy(dev->vdev->config, &s->blkcfg, sizeof(struct virtio_blk_config));
virtio_notify_config(dev->vdev);
}
return 0;
}
const VhostDevConfigOps blk_ops = {
.vhost_dev_config_notifier = vhost_user_blk_handle_config_change,
};
static int vhost_user_blk_start(VirtIODevice *vdev)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int i, ret;
if (!k->set_guest_notifiers) {
error_report("binding does not support guest notifiers");
return -ENOSYS;
}
ret = vhost_dev_enable_notifiers(&s->dev, vdev);
if (ret < 0) {
error_report("Error enabling host notifiers: %d", -ret);
return ret;
}
ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, true);
if (ret < 0) {
error_report("Error binding guest notifier: %d", -ret);
goto err_host_notifiers;
}
s->dev.acked_features = vdev->guest_features;
if (!s->inflight->addr) {
ret = vhost_dev_get_inflight(&s->dev, s->queue_size, s->inflight);
if (ret < 0) {
error_report("Error get inflight: %d", -ret);
goto err_guest_notifiers;
}
}
ret = vhost_dev_set_inflight(&s->dev, s->inflight);
if (ret < 0) {
error_report("Error set inflight: %d", -ret);
goto err_guest_notifiers;
}
ret = vhost_dev_start(&s->dev, vdev);
if (ret < 0) {
error_report("Error starting vhost: %d", -ret);
goto err_guest_notifiers;
}
s->started_vu = true;
/* 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 < s->dev.nvqs; i++) {
vhost_virtqueue_mask(&s->dev, vdev, i, false);
}
return ret;
err_guest_notifiers:
k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&s->dev, vdev);
return ret;
}
static void vhost_user_blk_stop(VirtIODevice *vdev)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
int ret;
if (!s->started_vu) {
return;
}
s->started_vu = false;
if (!k->set_guest_notifiers) {
return;
}
vhost_dev_stop(&s->dev, vdev);
ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
if (ret < 0) {
error_report("vhost guest notifier cleanup failed: %d", ret);
return;
}
vhost_dev_disable_notifiers(&s->dev, vdev);
}
static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
bool should_start = virtio_device_started(vdev, status);
int ret;
if (!vdev->vm_running) {
should_start = false;
}
if (!s->connected) {
return;
}
if (s->dev.started == should_start) {
return;
}
if (should_start) {
ret = vhost_user_blk_start(vdev);
if (ret < 0) {
error_report("vhost-user-blk: vhost start failed: %s",
strerror(-ret));
qemu_chr_fe_disconnect(&s->chardev);
}
} else {
vhost_user_blk_stop(vdev);
}
}
static uint64_t vhost_user_blk_get_features(VirtIODevice *vdev,
uint64_t features,
Error **errp)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
/* Turn on pre-defined features */
virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
virtio_add_feature(&features, VIRTIO_BLK_F_RO);
virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
if (s->config_wce) {
virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
}
if (s->num_queues > 1) {
virtio_add_feature(&features, VIRTIO_BLK_F_MQ);
}
return vhost_get_features(&s->dev, user_feature_bits, features);
}
static void vhost_user_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
int i, ret;
if (!vdev->start_on_kick) {
return;
}
if (!s->connected) {
return;
}
if (s->dev.started) {
return;
}
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* vhost here instead of waiting for .set_status().
*/
ret = vhost_user_blk_start(vdev);
if (ret < 0) {
error_report("vhost-user-blk: vhost start failed: %s",
strerror(-ret));
qemu_chr_fe_disconnect(&s->chardev);
return;
}
/* Kick right away to begin processing requests already in vring */
for (i = 0; i < s->dev.nvqs; i++) {
VirtQueue *kick_vq = virtio_get_queue(vdev, i);
if (!virtio_queue_get_desc_addr(vdev, i)) {
continue;
}
event_notifier_set(virtio_queue_get_host_notifier(kick_vq));
}
}
static void vhost_user_blk_reset(VirtIODevice *vdev)
{
VHostUserBlk *s = VHOST_USER_BLK(vdev);
vhost_dev_free_inflight(s->inflight);
}
static int vhost_user_blk_connect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
int ret = 0;
if (s->connected) {
return 0;
}
s->connected = true;
s->dev.nvqs = s->num_queues;
s->dev.vqs = s->vhost_vqs;
s->dev.vq_index = 0;
s->dev.backend_features = 0;
vhost_dev_set_config_notifier(&s->dev, &blk_ops);
ret = vhost_dev_init(&s->dev, &s->vhost_user, VHOST_BACKEND_TYPE_USER, 0);
if (ret < 0) {
error_report("vhost-user-blk: vhost initialization failed: %s",
strerror(-ret));
return ret;
}
/* restore vhost state */
if (virtio_device_started(vdev, vdev->status)) {
ret = vhost_user_blk_start(vdev);
if (ret < 0) {
error_report("vhost-user-blk: vhost start failed: %s",
strerror(-ret));
return ret;
}
}
return 0;
}
static void vhost_user_blk_disconnect(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
if (!s->connected) {
return;
}
s->connected = false;
vhost_user_blk_stop(vdev);
vhost_dev_cleanup(&s->dev);
}
static void vhost_user_blk_event(void *opaque, QEMUChrEvent event);
static void vhost_user_blk_chr_closed_bh(void *opaque)
{
DeviceState *dev = opaque;
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
vhost_user_blk_disconnect(dev);
qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
NULL, opaque, NULL, true);
}
static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
{
DeviceState *dev = opaque;
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
switch (event) {
case CHR_EVENT_OPENED:
if (vhost_user_blk_connect(dev) < 0) {
qemu_chr_fe_disconnect(&s->chardev);
return;
}
break;
case CHR_EVENT_CLOSED:
/*
* A close event may happen during a read/write, but vhost
* code assumes the vhost_dev remains setup, so delay the
* stop & clear. There are two possible paths to hit this
* disconnect event:
* 1. When VM is in the RUN_STATE_PRELAUNCH state. The
* vhost_user_blk_device_realize() is a caller.
* 2. In tha main loop phase after VM start.
*
* For p2 the disconnect event will be delayed. We can't
* do the same for p1, because we are not running the loop
* at this moment. So just skip this step and perform
* disconnect in the caller function.
*
* TODO: maybe it is a good idea to make the same fix
* for other vhost-user devices.
*/
if (runstate_is_running()) {
AioContext *ctx = qemu_get_current_aio_context();
qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL, NULL,
NULL, NULL, false);
aio_bh_schedule_oneshot(ctx, vhost_user_blk_chr_closed_bh, opaque);
}
/*
* Move vhost device to the stopped state. The vhost-user device
* will be clean up and disconnected in BH. This can be useful in
* the vhost migration code. If disconnect was caught there is an
* option for the general vhost code to get the dev state without
* knowing its type (in this case vhost-user).
*/
s->dev.started = false;
break;
case CHR_EVENT_BREAK:
case CHR_EVENT_MUX_IN:
case CHR_EVENT_MUX_OUT:
/* Ignore */
break;
}
}
static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(vdev);
Error *err = NULL;
int i, ret;
if (!s->chardev.chr) {
error_setg(errp, "vhost-user-blk: chardev is mandatory");
return;
}
if (s->num_queues == VHOST_USER_BLK_AUTO_NUM_QUEUES) {
s->num_queues = 1;
}
if (!s->num_queues || s->num_queues > VIRTIO_QUEUE_MAX) {
error_setg(errp, "vhost-user-blk: invalid number of IO queues");
return;
}
if (!s->queue_size) {
error_setg(errp, "vhost-user-blk: queue size must be non-zero");
return;
}
if (!vhost_user_init(&s->vhost_user, &s->chardev, errp)) {
return;
}
virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
sizeof(struct virtio_blk_config));
s->virtqs = g_new(VirtQueue *, s->num_queues);
for (i = 0; i < s->num_queues; i++) {
s->virtqs[i] = virtio_add_queue(vdev, s->queue_size,
vhost_user_blk_handle_output);
}
s->inflight = g_new0(struct vhost_inflight, 1);
s->vhost_vqs = g_new0(struct vhost_virtqueue, s->num_queues);
s->connected = false;
qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, vhost_user_blk_event,
NULL, (void *)dev, NULL, true);
reconnect:
if (qemu_chr_fe_wait_connected(&s->chardev, &err) < 0) {
error_report_err(err);
goto virtio_err;
}
/* check whether vhost_user_blk_connect() failed or not */
if (!s->connected) {
goto reconnect;
}
ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg,
sizeof(struct virtio_blk_config));
if (ret < 0) {
error_report("vhost-user-blk: get block config failed");
goto reconnect;
}
if (s->blkcfg.num_queues != s->num_queues) {
s->blkcfg.num_queues = s->num_queues;
}
return;
virtio_err:
g_free(s->vhost_vqs);
s->vhost_vqs = NULL;
g_free(s->inflight);
s->inflight = NULL;
for (i = 0; i < s->num_queues; i++) {
virtio_delete_queue(s->virtqs[i]);
}
g_free(s->virtqs);
virtio_cleanup(vdev);
vhost_user_cleanup(&s->vhost_user);
}
static void vhost_user_blk_device_unrealize(DeviceState *dev)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserBlk *s = VHOST_USER_BLK(dev);
int i;
virtio_set_status(vdev, 0);
qemu_chr_fe_set_handlers(&s->chardev, NULL, NULL, NULL,
NULL, NULL, NULL, false);
vhost_dev_cleanup(&s->dev);
vhost_dev_free_inflight(s->inflight);
g_free(s->vhost_vqs);
s->vhost_vqs = NULL;
g_free(s->inflight);
s->inflight = NULL;
for (i = 0; i < s->num_queues; i++) {
virtio_delete_queue(s->virtqs[i]);
}
g_free(s->virtqs);
virtio_cleanup(vdev);
vhost_user_cleanup(&s->vhost_user);
}
static void vhost_user_blk_instance_init(Object *obj)
{
VHostUserBlk *s = VHOST_USER_BLK(obj);
device_add_bootindex_property(obj, &s->bootindex, "bootindex",
"/disk@0,0", DEVICE(obj));
}
static const VMStateDescription vmstate_vhost_user_blk = {
.name = "vhost-user-blk",
.minimum_version_id = 1,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
};
static Property vhost_user_blk_properties[] = {
DEFINE_PROP_CHR("chardev", VHostUserBlk, chardev),
DEFINE_PROP_UINT16("num-queues", VHostUserBlk, num_queues,
VHOST_USER_BLK_AUTO_NUM_QUEUES),
DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
DEFINE_PROP_END_OF_LIST(),
};
static void vhost_user_blk_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
device_class_set_props(dc, vhost_user_blk_properties);
dc->vmsd = &vmstate_vhost_user_blk;
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
vdc->realize = vhost_user_blk_device_realize;
vdc->unrealize = vhost_user_blk_device_unrealize;
vdc->get_config = vhost_user_blk_update_config;
vdc->set_config = vhost_user_blk_set_config;
vdc->get_features = vhost_user_blk_get_features;
vdc->set_status = vhost_user_blk_set_status;
vdc->reset = vhost_user_blk_reset;
}
static const TypeInfo vhost_user_blk_info = {
.name = TYPE_VHOST_USER_BLK,
.parent = TYPE_VIRTIO_DEVICE,
.instance_size = sizeof(VHostUserBlk),
.instance_init = vhost_user_blk_instance_init,
.class_init = vhost_user_blk_class_init,
};
static void virtio_register_types(void)
{
type_register_static(&vhost_user_blk_info);
}
type_init(virtio_register_types)