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xemu/block/export/vduse-blk.c
Xie Yongji 779d82e1d3 vduse-blk: Add name option 
Currently we use 'id' option as the name of VDUSE device.
It's a bit confusing since we use one value for two different
purposes: the ID to identfy the export within QEMU (must be
distinct from any other exports in the same QEMU process, but
can overlap with names used by other processes), and the VDUSE
name to uniquely identify it on the host (must be distinct from
other VDUSE devices on the same host, but can overlap with other
export types like NBD in the same process). To make it clear,
this patch adds a separate 'name' option to specify the VDUSE
name for the vduse-blk export instead.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Message-Id: <20220614051532.92-7-xieyongji@bytedance.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-06-24 17:07:06 +02:00

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/*
* 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 <sys/eventfd.h>
#include "qemu/osdep.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;
} VduseBlkExport;
typedef struct VduseBlkReq {
VduseVirtqElement elem;
VduseVirtq *vq;
} VduseBlkReq;
static void vduse_blk_inflight_inc(VduseBlkExport *vblk_exp)
{
vblk_exp->inflight++;
}
static void vduse_blk_inflight_dec(VduseBlkExport *vblk_exp)
{
if (--vblk_exp->inflight == 0) {
aio_wait_kick();
}
}
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);
aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
true, on_vduse_vq_kick, NULL, NULL, NULL, vq);
/* Make sure we don't miss any kick afer 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);
aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
true, 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)
{
int i;
aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
true, on_vduse_dev_kick, NULL, NULL, NULL,
vblk_exp->dev);
for (i = 0; i < vblk_exp->num_queues; i++) {
VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
int fd = vduse_queue_get_fd(vq);
if (fd < 0) {
continue;
}
aio_set_fd_handler(vblk_exp->export.ctx, fd, true,
on_vduse_vq_kick, NULL, NULL, NULL, vq);
}
}
static void vduse_blk_detach_ctx(VduseBlkExport *vblk_exp)
{
int i;
for (i = 0; i < vblk_exp->num_queues; i++) {
VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
int fd = vduse_queue_get_fd(vq);
if (fd < 0) {
continue;
}
aio_set_fd_handler(vblk_exp->export.ctx, fd,
true, NULL, NULL, NULL, NULL, NULL);
}
aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
true, NULL, NULL, NULL, NULL, NULL);
AIO_WAIT_WHILE(vblk_exp->export.ctx, vblk_exp->inflight > 0);
}
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 const BlockDevOps vduse_block_ops = {
.resize_cb = vduse_blk_resize,
};
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->has_serial ?
vblk_opts->serial : "");
vblk_exp->handler.logical_block_size = logical_block_size;
vblk_exp->handler.writable = opts->writable;
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), true,
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);
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;
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vblk_exp);
blk_set_dev_ops(exp->blk, NULL, NULL);
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);
}
static void vduse_blk_exp_request_shutdown(BlockExport *exp)
{
VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
aio_context_acquire(vblk_exp->export.ctx);
vduse_blk_detach_ctx(vblk_exp);
aio_context_acquire(vblk_exp->export.ctx);
}
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,
};
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