--- /dev/null
+/*
+ * 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;
+ 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);
+}
+
+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 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;
+
+ 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 = exp->id;
+ 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(exp->id, 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");
+ return -ENOMEM;
+ }
+
+ 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);
+
+ return 0;
+}
+
+static void vduse_blk_exp_delete(BlockExport *exp)
+{
+ VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
+
+ blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+ vblk_exp);
+ vduse_dev_destroy(vblk_exp->dev);
+}
+
+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,
+};
projects / qemu-nvme.git / commitdiff