From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_05,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE778C433E0 for ; Wed, 10 Mar 2021 07:14:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 820A764FED for ; Wed, 10 Mar 2021 07:14:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229632AbhCJHNw (ORCPT ); Wed, 10 Mar 2021 02:13:52 -0500 Received: from mail177-27.suw61.mandrillapp.com ([198.2.177.27]:43880 "EHLO mail177-27.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229441AbhCJHN1 (ORCPT ); Wed, 10 Mar 2021 02:13:27 -0500 X-Greylist: delayed 902 seconds by postgrey-1.27 at vger.kernel.org; Wed, 10 Mar 2021 02:13:27 EST DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; s=mandrill; d=nexedi.com; h=From:Subject:To:Message-Id:Date:MIME-Version:Content-Type:Content-Transfer-Encoding; i=vincent@nexedi.com; bh=clByO+YyjeNz5x5NMjsaqhUb+yntq/+4EVnS+9KNQUc=; b=OIdLUXMt3J6V+Nsz/DMfmA4cKU7f0CenExK0f362ymGDfs6SCDqYUsZu3+6hZk1F856lrIFR9HOz s6EXmmm/kRvp6cmJPhEXJODF/7iaxYhucjByEDLNg2ltOvSmc1AO6cLirnUKDOWNexXs+mrmfApN ESvVLjjEL1+9EQBKjNk= Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-27.suw61.mandrillapp.com id h91ope22rtk4 for ; Wed, 10 Mar 2021 06:58:22 +0000 (envelope-from ) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mandrillapp.com; i=@mandrillapp.com; q=dns/txt; s=mandrill; t=1615359502; h=From : Subject : To : Message-Id : Date : MIME-Version : Content-Type : Content-Transfer-Encoding : From : Subject : Date : X-Mandrill-User : List-Unsubscribe; bh=clByO+YyjeNz5x5NMjsaqhUb+yntq/+4EVnS+9KNQUc=; b=gUXaddkgQ84Ea6pEMD21IN7VuUCXSySFuw7jIdFRqG8eN3FT5Rh8T/U+Pv3zLF52UB91fp CmCmXhaUQyqleOfPlnq1TPg3OoV6R2YpZYuu4or3PSCD1FXELVKkL0N5QKvP9vB29cG2WZiy mAlXgE/h76ai0IoTPUrymEsqdJZjA= From: Vincent Pelletier Subject: Is vHost reversible ? Received: from [87.98.221.171] by mandrillapp.com id d90cbedd86df4bd4b60cef165ba0f632; Wed, 10 Mar 2021 06:58:22 +0000 X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) To: target-devel@vger.kernel.org Message-Id: <20210310155813.7bef9aca@vincent-tkpad> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=31050260.d90cbedd86df4bd4b60cef165ba0f632 X-Mandrill-User: md_31050260 Date: Wed, 10 Mar 2021 06:58:22 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org Hello, (please keep me CC'ed, I'm not subscribed) I have a NVMe-like high-performance storage device which requires a proprietary module to work. Because it is not upstream, I tend to distrust by default its quality, and I want to isolate it from the rest of the machine. I did this by using PCI virtualisation, so now I have a qemu-kvm running a kernel with the proprietary module, and containing the block device, and I want to expose this block device back to the host (where the databases desiring to access this block device will run). If I ignore the hypervisor/VM relationship, I would be tempted to setup an iSCSI target over the network, but I am worried about the overhead. But with this special relationship in mind, I would like to use vHost-like, just in the exact opposite way (VM has the backstore, host is the initiator and gets a block device), and likely get a lower overhead. Is this possible ? I am quite new to the whole virtio family, so please forgive me if the answer is blindingly obvious. -- Vincent Pelletier ERP5 - open source ERP/CRM for flexible enterprises