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([183.221.93.83]) by smtp.gmail.com with ESMTPSA id y6-20020aa793c6000000b00540d75197e5sm731994pff.47.2022.09.09.22.29.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Sep 2022 22:29:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=BFPxl3nAGF1rBBCyjnFCSTHHYUfwTOepHasYOlesocs=; b=TxqlioPqylUedUAcHybaQxUM1WTbi3l7GuJJasambQ8FcEB/UfA6PKG0Ey8okeIVhA DqkAtcsmf12dQhDLtPCjd739Bu9fvQBLMWiMbSRSWEY3Vyr+5EJluFGCQDnFhxT/8JqO 3GA5w2LUznXYRbKNhHulT6UP8t+inaesdK+xmg8GuMsUxrQb5zDMn6se2MsJ/DuXcHir wS2DZQmRJ93swu/z7mzUMa1XoZp0wlqY8BmyB+rZWjYAnYA/ZGuaPX5Q4nOL7xA9AC76 rzI6F0PK1HAKREL3l5QpM/iKS2RzpwNHkyvsIP5kPJVKezSrPf8Xy4hZfKYjEpw7whZ0 LGfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date; bh=BFPxl3nAGF1rBBCyjnFCSTHHYUfwTOepHasYOlesocs=; b=J2pwzQlYIlEgPVQbTD83TC9I/jfZF1IUfkLsZ/z5EGFVIAHSHdpW2pSMlWaleOg+fm 74H4JMpHoulBZzD/bSpdTErqPqBegdl4O/HbI6aOzsXKkGIwV1k09upZgF8NvU2oWlcj Qkgv7kR2J2qCUMA0hW5uQyiwui4DF4LB0Fyqn6BS5UAS4ykIByxZiyg67UZTwlEhI03G yoQdAt9PIWguPie0qxnJrWN0d5K72K8ahKirdXCokxAvwSqG7qxSRtgm1hPUhHDbemIU 4KNwo2700tNbX5WpXTmWtSfk6TIzyq6PN9YJHQc8aBRlGtsviCpq8GmaSuq/oC9Km9Ja 6MyQ== X-Gm-Message-State: ACgBeo0QtHlRAEcnERwJEo9S3DvObZcDWygtEvpumTMUVFiR8CcJuEH7 QRr7BEcnDrfTrqvz1Oy3sZUPoWticaqaw1Cj X-Google-Smtp-Source: AA6agR7iNHjln9Jjq5onrNpIBRerig6eOu0gS6cr34m73X4Zl0mR5Ph2XOFicXD1F550rXRG9PWD+A== X-Received: by 2002:a17:902:f545:b0:178:12e5:9efa with SMTP id h5-20020a170902f54500b0017812e59efamr3875736plf.100.1662787760682; Fri, 09 Sep 2022 22:29:20 -0700 (PDT) From: Sam Li To: qemu-devel@nongnu.org Cc: dmitry.fomichev@wdc.com, Markus Armbruster , Eric Blake , qemu-block@nongnu.org, Stefan Hajnoczi , Kevin Wolf , Fam Zheng , damien.lemoal@opensource.wdc.com, hare@suse.de, Hanna Reitz , Sam Li Subject: [PATCH v9 7/7] docs/zoned-storage: add zoned device documentation Date: Sat, 10 Sep 2022 13:27:59 +0800 Message-Id: <20220910052759.27517-8-faithilikerun@gmail.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220910052759.27517-1-faithilikerun@gmail.com> References: <20220910052759.27517-1-faithilikerun@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::62a; envelope-from=faithilikerun@gmail.com; helo=mail-pl1-x62a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1662788025708100001 Content-Type: text/plain; charset="utf-8" Add the documentation about the zoned device support to virtio-blk emulation. Signed-off-by: Sam Li Reviewed-by: Stefan Hajnoczi --- docs/devel/zoned-storage.rst | 41 ++++++++++++++++++++++++++ docs/system/qemu-block-drivers.rst.inc | 6 ++++ 2 files changed, 47 insertions(+) create mode 100644 docs/devel/zoned-storage.rst diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst new file mode 100644 index 0000000000..ead2d149cc --- /dev/null +++ b/docs/devel/zoned-storage.rst @@ -0,0 +1,41 @@ +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D +zoned-storage +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D + +Zoned Block Devices (ZBDs) devide the LBA space into block regions called = zones +that are larger than the LBA size. It can only allow sequential writes, wh= ich +reduces write amplification in SSDs, leading to higher throughput and incr= eased +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 has three zoned storage model: +- BLK_Z_HM: This model only allows sequential writes access. It supports a= set +of ZBD-specific I/O request that used by the host to manage device zones. +- BLK_Z_HA: It deals with both sequential writes and random writes access. +- BLK_Z_NONE: Regular block devices and drive-managed ZBDs are treated as +non-zoned devices. + +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 point= er 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 de= vice. + +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, the command line for zone report testing a null_blk device of +qemu-io-cmds.c is: +$ path/to/qemu-io --image-opts driver=3Dzoned_host_device,filename=3D/dev/= nullb0 -c +"zrp offset nr_zones" diff --git a/docs/system/qemu-block-drivers.rst.inc b/docs/system/qemu-bloc= k-drivers.rst.inc index dfe5d2293d..0b97227fd9 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). =20 +Zoned block devices + Zoned block devices can be passed through to the guest if the emulated s= torage + controller supports zoned storage. Use ``--blockdev zoned_host_device, + node-name=3Ddrive0,filename=3D/dev/nullb0`` to pass through ``/dev/nullb= 0`` + as ``drive0``. + Windows ^^^^^^^ =20 --=20 2.37.3