This implements a VDUSE block backends based on
the libvduse library. We can use it to export the BDSs
for both VM and container (host) usage.
The new command-line syntax is:
$ qemu-storage-daemon \
--blockdev file,node-name=drive0,filename=test.img \
--export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
After the qemu-storage-daemon started, we need to use
the "vdpa" command to attach the device to vDPA bus:
$ vdpa dev add name vduse-export0 mgmtdev vduse
Also the device must be removed via the "vdpa" command
before we stop the qemu-storage-daemon.
Signed-off-by: Xie Yongji
---
MAINTAINERS | 4 +-
block/export/export.c | 6 +
block/export/meson.build | 5 +
block/export/vduse-blk.c | 312 ++
block/export/vduse-blk.h | 20 +++
meson.build | 13 ++
meson_options.txt | 2 +
qapi/block-export.json| 25 ++-
scripts/meson-buildoptions.sh | 4 +
9 files changed, 388 insertions(+), 3 deletions(-)
create mode 100644 block/export/vduse-blk.c
create mode 100644 block/export/vduse-blk.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 6de3cbaa1e..704489e50d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3550,10 +3550,12 @@ L: qemu-bl...@nongnu.org
S: Supported
F: block/export/fuse.c
-VDUSE library
+VDUSE library and block device exports
M: Xie Yongji
S: Maintained
F: subprojects/libvduse/
+F: block/export/vduse-blk.c
+F: block/export/vduse-blk.h
Replication
M: Wen Congyang
diff --git a/block/export/export.c b/block/export/export.c
index 7253af3bc3..4744862915 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -26,6 +26,9 @@
#ifdef CONFIG_VHOST_USER_BLK_SERVER
#include "vhost-user-blk-server.h"
#endif
+#ifdef CONFIG_VDUSE_BLK_EXPORT
+#include "vduse-blk.h"
+#endif
static const BlockExportDriver *blk_exp_drivers[] = {
_exp_nbd,
@@ -35,6 +38,9 @@ static const BlockExportDriver *blk_exp_drivers[] = {
#ifdef CONFIG_FUSE
_exp_fuse,
#endif
+#ifdef CONFIG_VDUSE_BLK_EXPORT
+_exp_vduse_blk,
+#endif
};
/* Only accessed from the main thread */
diff --git a/block/export/meson.build b/block/export/meson.build
index 431e47ca51..c60116f455 100644
--- a/block/export/meson.build
+++ b/block/export/meson.build
@@ -5,3 +5,8 @@ if have_vhost_user_blk_server
endif
blockdev_ss.add(when: fuse, if_true: files('fuse.c'))
+
+if have_vduse_blk_export
+blockdev_ss.add(files('vduse-blk.c', 'virtio-blk-handler.c'))
+blockdev_ss.add(libvduse)
+endif
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c
new file mode 100644
index 00..8580ae929f
--- /dev/null
+++ b/block/export/vduse-blk.c
@@ -0,0 +1,312 @@
+/*
+ * Export QEMU block device via VDUSE
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights
reserved.
+ * Portions of codes and concepts borrowed from vhost-user-blk-server.c, so:
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * Author:
+ * Xie Yongji
+ * Coiby Xu
+ *
+ * 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
+
+#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;
+VduseDev *dev;
+uint16_t num_queues;
+bool writable;
+} VduseBlkExport;
+
+typedef struct VduseBlkReq {
+VduseVirtqElement elem;
+VduseVirtq *vq;
+} VduseBlkReq;
+
+static void vduse_blk_req_complete(VduseBlkReq *req, size_t in_len)
+{
+vduse_queue_push(req->vq, >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);
+BlockBackend *blk = vblk_exp->export.blk;
+VduseVirtqElement *elem = >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(blk, vblk_exp->writable,
+vblk_exp->export.id, in_iov,
+out_iov, in_num, out_num);
+if (in_len < 0) {
+free(req);
+return;
+}
+
+vduse_blk_req_complete(req, in_len);
+}
+
+static void vduse_blk_vq_handler(VduseDev *dev, VduseVirtq *vq)
+{
+while (1) {
+VduseBlkReq *req;
+
+req = vduse_queue_pop(vq, sizeof(VduseBlkReq));
+if (!req) {
+break;
+}
