blob: 172f73cef44ae7befd8ea2e6cd270f513c5707ff [file] [log] [blame]
/*
* Export QEMU block device via VDUSE
*
* Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
*
* Author:
* Xie Yongji <xieyongji@bytedance.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <sys/eventfd.h>
#include "qapi/error.h"
#include "block/export.h"
#include "qemu/error-report.h"
#include "util/block-helpers.h"
#include "subprojects/libvduse/libvduse.h"
#include "virtio-blk-handler.h"
#include "standard-headers/linux/virtio_blk.h"
#define VDUSE_DEFAULT_NUM_QUEUE 1
#define VDUSE_DEFAULT_QUEUE_SIZE 256
typedef struct VduseBlkExport {
BlockExport export;
VirtioBlkHandler handler;
VduseDev *dev;
uint16_t num_queues;
char *recon_file;
unsigned int inflight; /* atomic */
bool vqs_started;
} VduseBlkExport;
typedef struct VduseBlkReq {
VduseVirtqElement elem;
VduseVirtq *vq;
} VduseBlkReq;
static void vduse_blk_inflight_inc(VduseBlkExport *vblk_exp)
{
if (qatomic_fetch_inc(&vblk_exp->inflight) == 0) {
/* Prevent export from being deleted */
blk_exp_ref(&vblk_exp->export);
}
}
static void vduse_blk_inflight_dec(VduseBlkExport *vblk_exp)
{
if (qatomic_fetch_dec(&vblk_exp->inflight) == 1) {
/* Wake AIO_WAIT_WHILE() */
aio_wait_kick();
/* Now the export can be deleted */
blk_exp_unref(&vblk_exp->export);
}
}
static void vduse_blk_req_complete(VduseBlkReq *req, size_t in_len)
{
vduse_queue_push(req->vq, &req->elem, in_len);
vduse_queue_notify(req->vq);
free(req);
}
static void coroutine_fn vduse_blk_virtio_process_req(void *opaque)
{
VduseBlkReq *req = opaque;
VduseVirtq *vq = req->vq;
VduseDev *dev = vduse_queue_get_dev(vq);
VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
VirtioBlkHandler *handler = &vblk_exp->handler;
VduseVirtqElement *elem = &req->elem;
struct iovec *in_iov = elem->in_sg;
struct iovec *out_iov = elem->out_sg;
unsigned in_num = elem->in_num;
unsigned out_num = elem->out_num;
int in_len;
in_len = virtio_blk_process_req(handler, in_iov,
out_iov, in_num, out_num);
if (in_len < 0) {
free(req);
return;
}
vduse_blk_req_complete(req, in_len);
vduse_blk_inflight_dec(vblk_exp);
}
static void vduse_blk_vq_handler(VduseDev *dev, VduseVirtq *vq)
{
VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
while (1) {
VduseBlkReq *req;
req = vduse_queue_pop(vq, sizeof(VduseBlkReq));
if (!req) {
break;
}
req->vq = vq;
Coroutine *co =
qemu_coroutine_create(vduse_blk_virtio_process_req, req);
vduse_blk_inflight_inc(vblk_exp);
qemu_coroutine_enter(co);
}
}
static void on_vduse_vq_kick(void *opaque)
{
VduseVirtq *vq = opaque;
VduseDev *dev = vduse_queue_get_dev(vq);
int fd = vduse_queue_get_fd(vq);
eventfd_t kick_data;
if (eventfd_read(fd, &kick_data) == -1) {
error_report("failed to read data from eventfd");
return;
}
vduse_blk_vq_handler(dev, vq);
}
static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq)
{
VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
if (!vblk_exp->vqs_started) {
return; /* vduse_blk_drained_end() will start vqs later */
}
aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
on_vduse_vq_kick, NULL, NULL, NULL, vq);
/* Make sure we don't miss any kick after reconnecting */
eventfd_write(vduse_queue_get_fd(vq), 1);
}
static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq)
{
VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
int fd = vduse_queue_get_fd(vq);
if (fd < 0) {
return;
}
aio_set_fd_handler(vblk_exp->export.ctx, fd,
NULL, NULL, NULL, NULL, NULL);
}
static const VduseOps vduse_blk_ops = {
.enable_queue = vduse_blk_enable_queue,
.disable_queue = vduse_blk_disable_queue,
};
static void on_vduse_dev_kick(void *opaque)
{
VduseDev *dev = opaque;
vduse_dev_handler(dev);
}
static void vduse_blk_attach_ctx(VduseBlkExport *vblk_exp, AioContext *ctx)
{
aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
on_vduse_dev_kick, NULL, NULL, NULL,
vblk_exp->dev);
/* Virtqueues are handled by vduse_blk_drained_end() */
}
static void vduse_blk_detach_ctx(VduseBlkExport *vblk_exp)
{
aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
NULL, NULL, NULL, NULL, NULL);
/* Virtqueues are handled by vduse_blk_drained_begin() */
}
static void blk_aio_attached(AioContext *ctx, void *opaque)
{
VduseBlkExport *vblk_exp = opaque;
vblk_exp->export.ctx = ctx;
vduse_blk_attach_ctx(vblk_exp, ctx);
}
static void blk_aio_detach(void *opaque)
{
VduseBlkExport *vblk_exp = opaque;
vduse_blk_detach_ctx(vblk_exp);
vblk_exp->export.ctx = NULL;
}
static void vduse_blk_resize(void *opaque)
{
BlockExport *exp = opaque;
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
struct virtio_blk_config config;
config.capacity =
cpu_to_le64(blk_getlength(exp->blk) >> VIRTIO_BLK_SECTOR_BITS);
vduse_dev_update_config(vblk_exp->dev, sizeof(config.capacity),
offsetof(struct virtio_blk_config, capacity),
(char *)&config.capacity);
}
static void vduse_blk_stop_virtqueues(VduseBlkExport *vblk_exp)
{
for (uint16_t i = 0; i < vblk_exp->num_queues; i++) {
VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
vduse_blk_disable_queue(vblk_exp->dev, vq);
}
vblk_exp->vqs_started = false;
}
static void vduse_blk_start_virtqueues(VduseBlkExport *vblk_exp)
{
vblk_exp->vqs_started = true;
for (uint16_t i = 0; i < vblk_exp->num_queues; i++) {
VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
vduse_blk_enable_queue(vblk_exp->dev, vq);
}
}
static void vduse_blk_drained_begin(void *opaque)
{
BlockExport *exp = opaque;
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
vduse_blk_stop_virtqueues(vblk_exp);
}
static void vduse_blk_drained_end(void *opaque)
{
BlockExport *exp = opaque;
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
vduse_blk_start_virtqueues(vblk_exp);
}
static bool vduse_blk_drained_poll(void *opaque)
{
BlockExport *exp = opaque;
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
return qatomic_read(&vblk_exp->inflight) > 0;
}
static const BlockDevOps vduse_block_ops = {
.resize_cb = vduse_blk_resize,
.drained_begin = vduse_blk_drained_begin,
.drained_end = vduse_blk_drained_end,
.drained_poll = vduse_blk_drained_poll,
};
static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
Error **errp)
{
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
BlockExportOptionsVduseBlk *vblk_opts = &opts->u.vduse_blk;
uint64_t logical_block_size = VIRTIO_BLK_SECTOR_SIZE;
uint16_t num_queues = VDUSE_DEFAULT_NUM_QUEUE;
uint16_t queue_size = VDUSE_DEFAULT_QUEUE_SIZE;
Error *local_err = NULL;
struct virtio_blk_config config = { 0 };
uint64_t features;
int i, ret;
if (vblk_opts->has_num_queues) {
num_queues = vblk_opts->num_queues;
if (num_queues == 0) {
error_setg(errp, "num-queues must be greater than 0");
return -EINVAL;
}
}
if (vblk_opts->has_queue_size) {
queue_size = vblk_opts->queue_size;
if (queue_size <= 2 || !is_power_of_2(queue_size) ||
queue_size > VIRTQUEUE_MAX_SIZE) {
error_setg(errp, "queue-size is invalid");
return -EINVAL;
}
}
if (vblk_opts->has_logical_block_size) {
logical_block_size = vblk_opts->logical_block_size;
check_block_size(exp->id, "logical-block-size", logical_block_size,
&local_err);
if (local_err) {
error_propagate(errp, local_err);
return -EINVAL;
}
}
vblk_exp->num_queues = num_queues;
vblk_exp->handler.blk = exp->blk;
vblk_exp->handler.serial = g_strdup(vblk_opts->serial ?: "");
vblk_exp->handler.logical_block_size = logical_block_size;
vblk_exp->handler.writable = opts->writable;
vblk_exp->vqs_started = true;
config.capacity =
cpu_to_le64(blk_getlength(exp->blk) >> VIRTIO_BLK_SECTOR_BITS);
config.seg_max = cpu_to_le32(queue_size - 2);
config.min_io_size = cpu_to_le16(1);
config.opt_io_size = cpu_to_le32(1);
config.num_queues = cpu_to_le16(num_queues);
config.blk_size = cpu_to_le32(logical_block_size);
config.max_discard_sectors = cpu_to_le32(VIRTIO_BLK_MAX_DISCARD_SECTORS);
config.max_discard_seg = cpu_to_le32(1);
config.discard_sector_alignment =
cpu_to_le32(logical_block_size >> VIRTIO_BLK_SECTOR_BITS);
config.max_write_zeroes_sectors =
cpu_to_le32(VIRTIO_BLK_MAX_WRITE_ZEROES_SECTORS);
config.max_write_zeroes_seg = cpu_to_le32(1);
features = vduse_get_virtio_features() |
(1ULL << VIRTIO_BLK_F_SEG_MAX) |
(1ULL << VIRTIO_BLK_F_TOPOLOGY) |
(1ULL << VIRTIO_BLK_F_BLK_SIZE) |
(1ULL << VIRTIO_BLK_F_FLUSH) |
(1ULL << VIRTIO_BLK_F_DISCARD) |
(1ULL << VIRTIO_BLK_F_WRITE_ZEROES);
if (num_queues > 1) {
features |= 1ULL << VIRTIO_BLK_F_MQ;
}
if (!opts->writable) {
features |= 1ULL << VIRTIO_BLK_F_RO;
}
vblk_exp->dev = vduse_dev_create(vblk_opts->name, VIRTIO_ID_BLOCK, 0,
features, num_queues,
sizeof(struct virtio_blk_config),
(char *)&config, &vduse_blk_ops,
vblk_exp);
if (!vblk_exp->dev) {
error_setg(errp, "failed to create vduse device");
ret = -ENOMEM;
goto err_dev;
}
vblk_exp->recon_file = g_strdup_printf("%s/vduse-blk-%s",
g_get_tmp_dir(), vblk_opts->name);
if (vduse_set_reconnect_log_file(vblk_exp->dev, vblk_exp->recon_file)) {
error_setg(errp, "failed to set reconnect log file");
ret = -EINVAL;
goto err;
}
for (i = 0; i < num_queues; i++) {
vduse_dev_setup_queue(vblk_exp->dev, i, queue_size);
}
aio_set_fd_handler(exp->ctx, vduse_dev_get_fd(vblk_exp->dev),
on_vduse_dev_kick, NULL, NULL, NULL, vblk_exp->dev);
blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vblk_exp);
blk_set_dev_ops(exp->blk, &vduse_block_ops, exp);
/*
* We handle draining ourselves using an in-flight counter and by disabling
* virtqueue fd handlers. Do not queue BlockBackend requests, they need to
* complete so the in-flight counter reaches zero.
*/
blk_set_disable_request_queuing(exp->blk, true);
return 0;
err:
vduse_dev_destroy(vblk_exp->dev);
g_free(vblk_exp->recon_file);
err_dev:
g_free(vblk_exp->handler.serial);
return ret;
}
static void vduse_blk_exp_delete(BlockExport *exp)
{
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
int ret;
assert(qatomic_read(&vblk_exp->inflight) == 0);
vduse_blk_detach_ctx(vblk_exp);
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vblk_exp);
ret = vduse_dev_destroy(vblk_exp->dev);
if (ret != -EBUSY) {
unlink(vblk_exp->recon_file);
}
g_free(vblk_exp->recon_file);
g_free(vblk_exp->handler.serial);
}
/* Called with exp->ctx acquired */
static void vduse_blk_exp_request_shutdown(BlockExport *exp)
{
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
vduse_blk_stop_virtqueues(vblk_exp);
}
const BlockExportDriver blk_exp_vduse_blk = {
.type = BLOCK_EXPORT_TYPE_VDUSE_BLK,
.instance_size = sizeof(VduseBlkExport),
.create = vduse_blk_exp_create,
.delete = vduse_blk_exp_delete,
.request_shutdown = vduse_blk_exp_request_shutdown,
};