From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Richard Henderson" <rth@twiddle.net>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Thomas Huth" <thuth@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Julia Suvorova" <jusual@redhat.com>,
"Aarushi Mehta" <mehta.aaru20@gmail.com>,
"Kevin Wolf" <kwolf@redhat.com>,
kvm@vger.kernel.org, "Stefan Hajnoczi" <stefanha@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Cornelia Huck" <cohuck@redhat.com>,
"Raphael Norwitz" <raphael.norwitz@nutanix.com>,
qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@linaro.org>,
"Hanna Reitz" <hreitz@redhat.com>,
"Eric Blake" <eblake@redhat.com>,
"Stefano Garzarella" <sgarzare@redhat.com>,
"Fam Zheng" <fam@euphon.net>, "Sam Li" <faithilikerun@gmail.com>,
"Damien Le Moal" <damien.lemoal@opensource.wdc.com>,
"Dmitry Fomichev" <dmitry.fomichev@wdc.com>
Subject: [PULL v2 08/16] docs/zoned-storage: add zoned device documentation
Date: Mon, 15 May 2023 12:04:58 -0400 [thread overview]
Message-ID: <20230515160506.1776883-9-stefanha@redhat.com> (raw)
In-Reply-To: <20230515160506.1776883-1-stefanha@redhat.com>
From: Sam Li <faithilikerun@gmail.com>
Add the documentation about the zoned device support to virtio-blk
emulation.
Signed-off-by: Sam Li <faithilikerun@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20230508045533.175575-9-faithilikerun@gmail.com
Message-id: 20230324090605.28361-9-faithilikerun@gmail.com
[Add index-api.rst to fix "zoned-storage.rst:document isn't included in
any toctree" error and fix pre-formatted code syntax.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
docs/devel/index-api.rst | 1 +
docs/devel/zoned-storage.rst | 43 ++++++++++++++++++++++++++
docs/system/qemu-block-drivers.rst.inc | 6 ++++
3 files changed, 50 insertions(+)
create mode 100644 docs/devel/zoned-storage.rst
diff --git a/docs/devel/index-api.rst b/docs/devel/index-api.rst
index 60c0d7459d..7108821746 100644
--- a/docs/devel/index-api.rst
+++ b/docs/devel/index-api.rst
@@ -12,3 +12,4 @@ generated from in-code annotations to function prototypes.
memory
modules
ui
+ zoned-storage
diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst
new file mode 100644
index 0000000000..da78db2783
--- /dev/null
+++ b/docs/devel/zoned-storage.rst
@@ -0,0 +1,43 @@
+=============
+zoned-storage
+=============
+
+Zoned Block Devices (ZBDs) divide the LBA space into block regions called zones
+that are larger than the LBA size. They can only allow sequential writes, which
+can reduce write amplification in SSDs, and potentially lead to higher
+throughput and increased capacity. More details about ZBDs can be found at:
+
+https://zonedstorage.io/docs/introduction/zoned-storage
+
+1. Block layer APIs for zoned storage
+-------------------------------------
+QEMU block layer supports three zoned storage models:
+- BLK_Z_HM: The host-managed zoned model only allows sequential writes access
+to zones. It supports ZBD-specific I/O commands that can be used by a host to
+manage the zones of a device.
+- BLK_Z_HA: The host-aware zoned model allows random write operations in
+zones, making it backward compatible with regular block devices.
+- BLK_Z_NONE: The non-zoned model has no zones support. It includes both
+regular and drive-managed ZBD devices. ZBD-specific I/O commands are not
+supported.
+
+The block device information resides inside BlockDriverState. QEMU uses
+BlockLimits struct(BlockDriverState::bl) that is continuously accessed by the
+block layer while processing I/O requests. A BlockBackend has a root pointer to
+a BlockDriverState graph(for example, raw format on top of file-posix). The
+zoned storage information can be propagated from the leaf BlockDriverState all
+the way up to the BlockBackend. If the zoned storage model in file-posix is
+set to BLK_Z_HM, then block drivers will declare support for zoned host device.
+
+The block layer APIs support commands needed for zoned storage devices,
+including report zones, four zone operations, and zone append.
+
+2. Emulating zoned storage controllers
+--------------------------------------
+When the BlockBackend's BlockLimits model reports a zoned storage device, users
+like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer
+APIs for zoned storage emulation or testing.
+
+For example, to test zone_report on a null_blk device using qemu-io is::
+
+ $ path/to/qemu-io --image-opts -n driver=host_device,filename=/dev/nullb0 -c "zrp offset nr_zones"
diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-block-drivers.rst.inc
index dfe5d2293d..105cb9679c 100644
--- a/docs/system/qemu-block-drivers.rst.inc
+++ b/docs/system/qemu-block-drivers.rst.inc
@@ -430,6 +430,12 @@ Hard disks
you may corrupt your host data (use the ``-snapshot`` command
line option or modify the device permissions accordingly).
+Zoned block devices
+ Zoned block devices can be passed through to the guest if the emulated storage
+ controller supports zoned storage. Use ``--blockdev host_device,
+ node-name=drive0,filename=/dev/nullb0,cache.direct=on`` to pass through
+ ``/dev/nullb0`` as ``drive0``.
+
Windows
^^^^^^^
--
2.40.1
next prev parent reply other threads:[~2023-05-15 16:07 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-15 16:04 [PULL v2 00/16] Block patches Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 01/16] block/block-common: add zoned device structs Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 02/16] block/file-posix: introduce helper functions for sysfs attributes Stefan Hajnoczi
[not found] ` <8b0ced3c-2fb5-2479-fe78-f4956ac037a6@linux.ibm.com>
2023-06-02 18:18 ` Sam Li
2023-06-02 18:41 ` Matthew Rosato
2023-06-02 18:45 ` Sam Li
2023-05-15 16:04 ` [PULL v2 03/16] block/block-backend: add block layer APIs resembling Linux ZonedBlockDevice ioctls Stefan Hajnoczi
2024-05-03 12:33 ` Peter Maydell
2024-05-07 15:09 ` Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 04/16] block/raw-format: add zone operations to pass through requests Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 05/16] block: add zoned BlockDriver check to block layer Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 06/16] iotests: test new zone operations Stefan Hajnoczi
2023-05-15 16:04 ` [PULL v2 07/16] block: add some trace events for new block layer APIs Stefan Hajnoczi
2023-05-15 16:04 ` Stefan Hajnoczi [this message]
2023-05-15 16:04 ` [PULL v2 09/16] file-posix: add tracking of the zone write pointers Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 10/16] block: introduce zone append write for zoned devices Stefan Hajnoczi
2023-06-02 16:51 ` Peter Maydell
2023-06-02 17:23 ` Sam Li
2023-06-02 17:30 ` Peter Maydell
2023-06-02 17:35 ` Sam Li
2023-06-02 17:52 ` Peter Maydell
2023-06-02 18:03 ` Sam Li
2023-05-15 16:05 ` [PULL v2 11/16] qemu-iotests: test zone append operation Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 12/16] block: add some trace events for zone append Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 13/16] virtio-blk: add zoned storage emulation for zoned devices Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 14/16] block: add accounting for zone append operation Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 15/16] virtio-blk: add some trace events for zoned emulation Stefan Hajnoczi
2023-05-15 16:05 ` [PULL v2 16/16] docs/zoned-storage:add zoned emulation use case Stefan Hajnoczi
2023-05-15 23:37 ` [PULL v2 00/16] Block patches Richard Henderson
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