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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 5CCB2C43331 for ; Mon, 11 Nov 2019 17:03:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FD92214E0 for ; Mon, 11 Nov 2019 17:03:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nTy5/J5u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726887AbfKKRDn (ORCPT ); Mon, 11 Nov 2019 12:03:43 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:39994 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726845AbfKKRDn (ORCPT ); Mon, 11 Nov 2019 12:03:43 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=jJ2XSvmWYSjH8U6K0+cFtVLMQGHVRVlZ4wb+eJcs2bM=; b=nTy5/J5uQXmgXT+1+meEgmTgk nnyQfpjO2QGevTyl3/hTL0I2Koi3cmSrTVF7BUorhPZKaE5uhy662x8TNptxqnuR91U6XDYT40Ocf 3bG3ui4+MdL8a3mpsVLGBO3Td0CZ5AVOjddPs58Kyt0WQZu/8Rp0WYq0UI7pde8hnhPcXyZzWKfWA /eiTfW2E4pwg9Y6AFjPg4fTkdGo5N46BZTaD1XxxZUAxdv79kBMNbeHjUBWaD1BJ7fYeoxCHZd7vl NQumPCDdcvcopw2Jwj8DRHjb0b00RIhKLDZlFUnc9vh8+mIxFatKHthRxHjPUESO07J3h4o4ZsHwx 1yZHdRSxg==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1iUD6K-00076k-EO; Mon, 11 Nov 2019 17:03:40 +0000 Date: Mon, 11 Nov 2019 09:03:40 -0800 From: "hch@infradead.org" To: "Derrick, Jonathan" Cc: "hch@infradead.org" , "kbusch@kernel.org" , "lorenzo.pieralisi@arm.com" , "linux-pci@vger.kernel.org" , "helgaas@kernel.org" Subject: Re: [PATCH 0/3] PCI: vmd: Reducing tail latency by affining to the storage stack Message-ID: <20191111170340.GA26474@infradead.org> References: <1573040408-3831-1-git-send-email-jonathan.derrick@intel.com> <20191107093952.GA13826@infradead.org> <20191107153736.GA16006@infradead.org> <20191107154224.GA26224@infradead.org> <784d25a41399472e80a0b384f88eccab29b01cc1.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <784d25a41399472e80a0b384f88eccab29b01cc1.camel@intel.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Nov 07, 2019 at 03:47:09PM +0000, Derrick, Jonathan wrote: > A cloud service provider might have several VMs on a single system and > wish to provide surprise hotplug functionality within the guests so > that they don't need to bring the whole server down or migrate VMs in > order to swap disks. And how does the vmd mechanism help with that? Maybe qemu is missing a memremap to not access the remove device right now, but adding that is way simpler than having to deal with a device that makes everyones life complicated.