From patchwork Fri Jan 12 08:55:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fam Zheng X-Patchwork-Id: 859666 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3zHxfQ6ZHGz9s75 for ; Fri, 12 Jan 2018 20:05:18 +1100 (AEDT) Received: from localhost ([::1]:55071 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZvH2-0005Uh-Ua for incoming@patchwork.ozlabs.org; Fri, 12 Jan 2018 04:05:17 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41686) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZvAv-0000m6-Fz for qemu-devel@nongnu.org; Fri, 12 Jan 2018 03:58:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZvAu-00053n-HJ for qemu-devel@nongnu.org; Fri, 12 Jan 2018 03:58:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57728) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eZvAs-0004zo-9M; Fri, 12 Jan 2018 03:58:54 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4C5692CE91D; Fri, 12 Jan 2018 08:58:53 +0000 (UTC) Received: from lemon.usersys.redhat.com (ovpn-12-81.pek2.redhat.com [10.72.12.81]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3794C75545; Fri, 12 Jan 2018 08:58:45 +0000 (UTC) From: Fam Zheng To: qemu-devel@nongnu.org Date: Fri, 12 Jan 2018 16:55:54 +0800 Message-Id: <20180112085555.14447-9-famz@redhat.com> In-Reply-To: <20180112085555.14447-1-famz@redhat.com> References: <20180112085555.14447-1-famz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 12 Jan 2018 08:58:53 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v5 8/9] docs: Add section for NVMe VFIO driver X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Markus Armbruster , Max Reitz , Keith Busch , alex.williamson@redhat.com, Stefan Hajnoczi , Paolo Bonzini , Karl Rister Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Signed-off-by: Fam Zheng Message-Id: <20180110091846.10699-9-famz@redhat.com> Reviewed-by: Stefan Hajnoczi --- docs/qemu-block-drivers.texi | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/docs/qemu-block-drivers.texi b/docs/qemu-block-drivers.texi index 503c1847aa..cd74767ed3 100644 --- a/docs/qemu-block-drivers.texi +++ b/docs/qemu-block-drivers.texi @@ -785,6 +785,43 @@ warning: ssh server @code{ssh.example.com:22} does not support fsync With sufficiently new versions of libssh2 and OpenSSH, @code{fsync} is supported. +@node disk_images_nvme +@subsection NVMe disk images + +NVM Express (NVMe) storage controllers can be accessed directly by a userspace +driver in QEMU. This bypasses the host kernel file system and block layers +while retaining QEMU block layer functionalities, such as block jobs, I/O +throttling, image formats, etc. Disk I/O performance is typically higher than +with @code{-drive file=/dev/sda} using either thread pool or linux-aio. + +The controller will be exclusively used by the QEMU process once started. To be +able to share storage between multiple VMs and other applications on the host, +please use the file based protocols. + +Before starting QEMU, bind the host NVMe controller to the host vfio-pci +driver. For example: + +@example +# modprobe vfio-pci +# lspci -n -s 0000:06:0d.0 +06:0d.0 0401: 1102:0002 (rev 08) +# echo 0000:06:0d.0 > /sys/bus/pci/devices/0000:06:0d.0/driver/unbind +# echo 1102 0002 > /sys/bus/pci/drivers/vfio-pci/new_id + +# qemu-system-x86_64 -drive file=nvme://@var{host}:@var{bus}:@var{slot}.@var{func}/@var{namespace} +@end example + +Alternative syntax using properties: + +@example +qemu-system-x86_64 -drive file.driver=nvme,file.device=@var{host}:@var{bus}:@var{slot}.@var{func},file.namespace=@var{namespace} +@end example + +@var{host}:@var{bus}:@var{slot}.@var{func} is the NVMe controller's PCI device +address on the host. + +@var{namespace} is the NVMe namespace number, starting from 1. + @node disk_image_locking @subsection Disk image file locking