Re: [Qemu-devel] [PATCH v4 4/4] contrib/vhost-user-blk: introduce a vhost-user-blk sample application

[Liu, Changpeng]

> -Original Message-
> From: Paolo Bonzini [mailto:pbonz...@redhat.com]
> Sent: Thursday, October 19, 2017 7:44 PM
> To: Liu, Changpeng ; qemu-devel@nongnu.org
> Cc: stefa...@gmail.com; m...@redhat.com; marcandre.lur...@redhat.com;
> fel...@nutanix.com; Harris, James R 
> Subject: Re: [PATCH v4 4/4] contrib/vhost-user-blk: introduce a vhost-user-blk
> sample application
> 
> On 19/10/2017 07:24, Changpeng Liu wrote:
> >
> > +}
> > +
> > +static void
> > +vub_flush(VubReq *req)
> > +{
> > +VubDev *vdev_blk = req->vdev_blk;
> > +
> > +if (vdev_blk->blk_fd) {
> > +fsync(vdev_blk->blk_fd);
> > +}
> > +}
> > +
> 
> No need to check the file descriptor---vub_readv and vub_writev aren't
> checking it either.  Also please use fdatasync instead of fsync.
Ok.
> 
> > +static uint64_t
> > +vub_get_features(VuDev *dev)
> > +{
> > +return 1ull << VIRTIO_BLK_F_SIZE_MAX |
> > +   1ull << VIRTIO_BLK_F_SEG_MAX |
> > +   1ull << VIRTIO_BLK_F_TOPOLOGY |
> > +   1ull << VIRTIO_BLK_F_BLK_SIZE |
> > +   1ull << VIRTIO_F_VERSION_1 |
> > +   1ull << VHOST_USER_F_PROTOCOL_FEATURES;
> > +}
> 
> VIRTIO_BLK_F_FLUSH is missing.
Yes, will add.
> 
> Thanks,
> 
> Paolo

Re: [Qemu-devel] [PATCH v4 4/4] contrib/vhost-user-blk: introduce a vhost-user-blk sample application

[Paolo Bonzini]

On 19/10/2017 07:24, Changpeng Liu wrote:
> 
> +}
> +
> +static void
> +vub_flush(VubReq *req)
> +{
> +VubDev *vdev_blk = req->vdev_blk;
> +
> +if (vdev_blk->blk_fd) {
> +fsync(vdev_blk->blk_fd);
> +}
> +}
> +

No need to check the file descriptor---vub_readv and vub_writev aren't
checking it either.  Also please use fdatasync instead of fsync.

> +static uint64_t
> +vub_get_features(VuDev *dev)
> +{
> +return 1ull << VIRTIO_BLK_F_SIZE_MAX |
> +   1ull << VIRTIO_BLK_F_SEG_MAX |
> +   1ull << VIRTIO_BLK_F_TOPOLOGY |
> +   1ull << VIRTIO_BLK_F_BLK_SIZE |
> +   1ull << VIRTIO_F_VERSION_1 |
> +   1ull << VHOST_USER_F_PROTOCOL_FEATURES;
> +}

VIRTIO_BLK_F_FLUSH is missing.

Thanks,

Paolo

[Qemu-devel] [PATCH v4 4/4] contrib/vhost-user-blk: introduce a vhost-user-blk sample application

[Changpeng Liu]

This commit introcudes a vhost-user-blk backend device, it uses UNIX
domain socket to communicate with Qemu. The vhost-user-blk sample
application should be used with Qemu vhost-user-blk-pci device.

To use it, complie with:
make vhost-user-blk

and start like this:
vhost-user-blk -b /dev/sdb -s /path/vhost.socket

Signed-off-by: Changpeng Liu 
---
 .gitignore  |   1 +
 Makefile|   3 +
 Makefile.objs   |   1 +
 contrib/vhost-user-blk/Makefile.objs|   1 +
 contrib/vhost-user-blk/vhost-user-blk.c | 492 
 5 files changed, 498 insertions(+)
 create mode 100644 contrib/vhost-user-blk/Makefile.objs
 create mode 100644 contrib/vhost-user-blk/vhost-user-blk.c

diff --git a/.gitignore b/.gitignore
index 620eec6..544276e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -53,6 +53,7 @@
 /scsi/qemu-pr-helper
 /vscclient
 /vhost-user-scsi
+/vhost-user-blk
 /fsdev/virtfs-proxy-helper
 *.tmp
 *.[1-9]
diff --git a/Makefile b/Makefile
index 90f91e5..be67a09 100644
--- a/Makefile
+++ b/Makefile
@@ -318,6 +318,7 @@ dummy := $(call unnest-vars,, \
 ivshmem-server-obj-y \
 libvhost-user-obj-y \
 vhost-user-scsi-obj-y \
+vhost-user-blk-obj-y \
 qga-vss-dll-obj-y \
 block-obj-y \
 block-obj-m \
@@ -534,6 +535,8 @@ ivshmem-server$(EXESUF): $(ivshmem-server-obj-y) 
$(COMMON_LDADDS)
 endif
 vhost-user-scsi$(EXESUF): $(vhost-user-scsi-obj-y) libvhost-user.a
$(call LINK, $^)
+vhost-user-blk$(EXESUF): $(vhost-user-blk-obj-y) libvhost-user.a
+   $(call LINK, $^)
 
 module_block.h: $(SRC_PATH)/scripts/modules/module_block.py config-host.mak
$(call quiet-command,$(PYTHON) $< $@ \
diff --git a/Makefile.objs b/Makefile.objs
index d4f973a..3af989d 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -115,6 +115,7 @@ libvhost-user-obj-y = contrib/libvhost-user/
 vhost-user-scsi.o-cflags := $(LIBISCSI_CFLAGS)
 vhost-user-scsi.o-libs := $(LIBISCSI_LIBS)
 vhost-user-scsi-obj-y = contrib/vhost-user-scsi/
+vhost-user-blk-obj-y = contrib/vhost-user-blk/
 
 ##
 trace-events-subdirs =
diff --git a/contrib/vhost-user-blk/Makefile.objs 
b/contrib/vhost-user-blk/Makefile.objs
new file mode 100644
index 000..72e2cdc
--- /dev/null
+++ b/contrib/vhost-user-blk/Makefile.objs
@@ -0,0 +1 @@
+vhost-user-blk-obj-y = vhost-user-blk.o
diff --git a/contrib/vhost-user-blk/vhost-user-blk.c 
b/contrib/vhost-user-blk/vhost-user-blk.c
new file mode 100644
index 000..45050bc
--- /dev/null
+++ b/contrib/vhost-user-blk/vhost-user-blk.c
@@ -0,0 +1,492 @@
+/*
+ * vhost-user-blk sample application
+ *
+ * Copyright IBM, Corp. 2007
+ * Copyright (c) 2016 Nutanix Inc. All rights reserved.
+ * Copyright (c) 2017 Intel Corporation. All rights reserved.
+ *
+ * Author:
+ *  Anthony Liguori 
+ *  Felipe Franciosi 
+ *  Changpeng Liu 
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 only.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "standard-headers/linux/virtio_blk.h"
+#include "contrib/libvhost-user/libvhost-user-glib.h"
+#include "contrib/libvhost-user/libvhost-user.h"
+
+#include 
+
+struct virtio_blk_inhdr {
+unsigned char status;
+};
+
+/* vhost user block device */
+typedef struct VubDev {
+VugDev parent;
+int blk_fd;
+struct virtio_blk_config blkcfg;
+char *blk_name;
+GMainLoop *loop;
+} VubDev;
+
+typedef struct VubReq {
+VuVirtqElement *elem;
+int64_t sector_num;
+size_t size;
+struct virtio_blk_inhdr *in;
+struct virtio_blk_outhdr *out;
+VubDev *vdev_blk;
+struct VuVirtq *vq;
+} VubReq;
+
+/**  refer util/iov.c  **/
+static size_t vub_iov_size(const struct iovec *iov,
+  const unsigned int iov_cnt)
+{
+size_t len;
+unsigned int i;
+
+len = 0;
+for (i = 0; i < iov_cnt; i++) {
+len += iov[i].iov_len;
+}
+return len;
+}
+
+static void vub_panic_cb(VuDev *vu_dev, const char *buf)
+{
+VugDev *gdev;
+VubDev *vdev_blk;
+
+assert(vu_dev);
+
+gdev = container_of(vu_dev, VugDev, parent);
+vdev_blk = container_of(gdev, VubDev, parent);
+if (buf) {
+g_warning("vu_panic: %s", buf);
+}
+
+g_main_loop_quit(vdev_blk->loop);
+}
+
+static void vub_req_complete(VubReq *req)
+{
+VugDev *gdev = >vdev_blk->parent;
+VuDev *vu_dev = >parent;
+
+/* IO size with 1 extra status byte */
+vu_queue_push(vu_dev, req->vq, req->elem,
+  req->size + 1);
+vu_queue_notify(vu_dev, req->vq);
+
+if (req->elem) {
+free(req->elem);
+}
+g_free(req);
+}
+
+static int vub_open(const char *file_name)
+{
+int fd;
+
+fd =