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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 AE31CC4646D for ; Mon, 6 Aug 2018 16:10:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6496E21A53 for ; Mon, 6 Aug 2018 16:10:50 +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="ashPT+2w" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6496E21A53 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733260AbeHFSUf (ORCPT ); Mon, 6 Aug 2018 14:20:35 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:56994 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733074AbeHFSUe (ORCPT ); Mon, 6 Aug 2018 14:20:34 -0400 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=nJMGUj3DeUam+8nHlM52EO2hR6Zo93W3LLkbctvVqtU=; b=ashPT+2wKD7vZHWJ/vmlJ1wnh +5kIZfCd67TuVDJCegbtL2nUdlOOn2btn9f/MVjmoaj5ErnPozqfcP35b1ZNeq1drVPj3q+gPRpiF p5GYUCyxa/mMEKOjptlCcXAkjy8a/+Zh6ZoMno1sxaOxd0Wy2BhwpDHjAu15+5GaxT0ITf6WhC4Mj 1UC7QxlhUAs/5RXCSDqPLt2sIExipHz187itnP+djlKWVB11FMiAiL2K50RPUFsQyJ6r47xgb9bh8 MMCIbB1dkBZZWu9XGY02LBtkZlXQII5MLTB0Hl7ex/iBz3L0EtLWAo2lxevMM/90TdQEA7Z5UNV/d cwWoUvTdA==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fmi5h-0002Ud-PA; Mon, 06 Aug 2018 16:10:41 +0000 Date: Mon, 6 Aug 2018 09:10:40 -0700 From: Christoph Hellwig To: "Michael S. Tsirkin" Cc: Christoph Hellwig , Anshuman Khandual , Benjamin Herrenschmidt , robh@kernel.org, srikar@linux.vnet.ibm.com, aik@ozlabs.ru, Jason Wang , linuxram@us.ibm.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, paulus@samba.org, joe@perches.com, david@gibson.dropbear.id.au, linuxppc-dev@lists.ozlabs.org, elfring@users.sourceforge.net, haren@linux.vnet.ibm.com Subject: Re: [RFC 0/4] Virtio uses DMA API for all devices Message-ID: <20180806161040.GA4675@infradead.org> References: <20180720035941.6844-1-khandual@linux.vnet.ibm.com> <20180802235332-mutt-send-email-mst@kernel.org> <20180803220812-mutt-send-email-mst@kernel.org> <01c74680c4b3aa25d9b4375a9ab5e10046b7c71b.camel@kernel.crashing.org> <20180805032355-mutt-send-email-mst@kernel.org> <74a1e1b8-81e0-84db-6d0d-d8bd9caebb4a@linux.vnet.ibm.com> <20180806163440-mutt-send-email-mst@kernel.org> <20180806152406.GA29020@infradead.org> <20180806190321-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180806190321-mutt-send-email-mst@kernel.org> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 06, 2018 at 07:06:05PM +0300, Michael S. Tsirkin wrote: > > I've done something very similar in the thread I posted a few years > > ago. > > Right so that was before spectre where a virtual call was cheaper :( Sorry, I meant days, not years. The whole point of the thread was the slowdowns due to retpolines, which are the software spectre mitigation.