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=-0.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 A0C25C432C3 for ; Thu, 21 Nov 2019 00:27:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78B4720715 for ; Thu, 21 Nov 2019 00:27:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="UsxjVTvi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726703AbfKUA14 (ORCPT ); Wed, 20 Nov 2019 19:27:56 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:41843 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726044AbfKUA14 (ORCPT ); Wed, 20 Nov 2019 19:27:56 -0500 Received: by mail-ot1-f67.google.com with SMTP id 94so1340285oty.8 for ; Wed, 20 Nov 2019 16:27:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RRno2ndEL0aLy2ekCq8SNn5kziBB2zvsTzrFr0XgIgU=; b=UsxjVTviHd1kq3bZY0wQXN4tO71PI7wZsg8+pSSo6kwk8/8EHAMXGv9vdcs9hutQlP 0leGxb9TacCeXprtwZiY3xsNY6gripp3Qc0tIXxhZ03aDz342HV0mW2x1q45x+bl6UWA VWJcMEKRUuHcLh1HZqqGctCaPdfbNFp2oLVjWSy0iWOfjwd4XhDxBMIP/lKIc3a7p/fF Y9NVorH1XEf/AfhzqEc8Ntbk1sS/Ox85kDbjLyXyR0BZ8Vo/WfNmRdG5MlXpopfqVJ+x dF64g8ETXHgomru5gvKmhahhIoBkVD30oGxPHoUxpVLudN14DWdVmlSpXrAs8wQDJWAL J9LQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RRno2ndEL0aLy2ekCq8SNn5kziBB2zvsTzrFr0XgIgU=; b=Ze7lj6IKP70GIiZBM8In/FtJwskQuSZZdbIN4AIXpcoIh+9dvd1kCGOBnH2hRDEX+T LhlihN/1/S8HegniTiorLhesK+XfTWEPQhktS+DUMSXjC6nuRy8qmRPHLVsorTS6XY/7 KlSV1U5PSJdZNzr9LCBxSCxuVQRUnEn/DOHspeqVaZkbl0QPs0I9iggENq+sSBsiTGTf ffWCMWB7ZjgBdrX5WVELWl09MA2UooOyMHJKkr7TgeRFsOS4UavikOCmqYzpFNpOJvU1 RKAy68KCDlaYL2gx99eb95WOAWgr0t2404ouoOdy7CqWQmCKCzXHQGn90372efO5syXk plDw== X-Gm-Message-State: APjAAAUwsP92VSVcpvmCg5gZrXtDPJFnyhAhKax6oiHQVG1GRCOEgS8M 8Ppb9Dgfot+eDxdaXa/DXyDiN3sQ0E8EeC4LudZ0BQ== X-Google-Smtp-Source: APXvYqydVUCALCV2gDjSgpUPjbBj1Jy2nVlG6eMJ9zJZGgKne8uQD9fRLPiO5DU7wqHm7+NmtFxuyY4SSgF+oSAxO8Y= X-Received: by 2002:a9d:2d89:: with SMTP id g9mr4139129otb.126.1574296075328; Wed, 20 Nov 2019 16:27:55 -0800 (PST) MIME-Version: 1.0 References: <157428480574.36836.14057238306923901253.stgit@djiang5-desk3.ch.intel.com> <157428502934.36836.8119026517510193201.stgit@djiang5-desk3.ch.intel.com> <20191120215338.GN2634@zn.tnic> <20191120231923.GA32680@agluck-desk2.amr.corp.intel.com> <20191120232645.GO2634@zn.tnic> In-Reply-To: <20191120232645.GO2634@zn.tnic> From: Dan Williams Date: Wed, 20 Nov 2019 16:27:43 -0800 Message-ID: Subject: Re: [PATCH RFC 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction To: Borislav Petkov Cc: "Luck, Tony" , Dave Jiang , dmaengine@vger.kernel.org, Linux Kernel Mailing List , Vinod Koul , Jing Lin , "Raj, Ashok" , "Kumar, Sanjay K" , "Dey, Megha" , "Pan, Jacob jun" , "Liu, Yi L" , Jens Axboe , Andrew Morton , Thomas Gleixner , Ingo Molnar , Fenghua Yu , "H. Peter Anvin" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 20, 2019 at 3:27 PM Borislav Petkov wrote: > > On Wed, Nov 20, 2019 at 03:19:23PM -0800, Luck, Tony wrote: > > That's the underlying functionality of the MOVDIR64B instruction. A > > posted write so no way to know if it succeeded. > > So how do you know whether any of the writes went through? It's identical to the writel() mmio-write to start a SATA command transfer. The higher level device driver protocol validates that the command went through, ultimately with a timeout. There's no return value for iosubmit_cmds512() for the same reason there's no return value for the other iowrite primitives.