From patchwork Tue Apr 27 12:51:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 12226689 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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 23373C43461 for ; Tue, 27 Apr 2021 12:52:25 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D6E62610A5 for ; Tue, 27 Apr 2021 12:52:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6E62610A5 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.118415.224512 (Exim 4.92) (envelope-from ) id 1lbNC6-0002j1-Kg; Tue, 27 Apr 2021 12:52:02 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 118415.224512; Tue, 27 Apr 2021 12:52:02 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lbNC6-0002iu-HI; Tue, 27 Apr 2021 12:52:02 +0000 Received: by outflank-mailman (input) for mailman id 118415; Tue, 27 Apr 2021 12:52:01 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lbNC5-0002ip-JH for xen-devel@lists.xenproject.org; Tue, 27 Apr 2021 12:52:01 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 462ed3de-a0a4-4632-9a81-72e20029f8b5; Tue, 27 Apr 2021 12:52:00 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D0F24B190; Tue, 27 Apr 2021 12:51:59 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 462ed3de-a0a4-4632-9a81-72e20029f8b5 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1619527919; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=Gbc0X2QS/6HUJBiSa/FTfSmvRkFaJfU/nMdzne667GI=; b=o/uqEfGJUDRAnec3Bvbq4H81ePpSu18IluizQyp6+6QFl5i4KneyFuXxytF54R95ruxesL EpjakhDIF8p3FFRVnHuTDd02R8Rsr1IURyiCukcxqD5HBGmsfOwYzRwyQBnKdFvg7y9xDB D+y4bE4zoir7G6guqM7LYBmiyvp61ZI= Cc: Andrew Cooper , Wei Liu , =?utf-8?q?Roger_Pau_Monn=C3=A9?= From: Jan Beulich Subject: [PATCH 0/7] x86: memcpy() / memset() (non-)ERMS flavors plus fallout To: "xen-devel@lists.xenproject.org" Message-ID: <6d6da76c-ccc8-afa2-bd06-5ae132c354f2@suse.com> Date: Tue, 27 Apr 2021 14:51:59 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 Content-Language: en-US While the performance varies quite a bit on older (pre-ERMS) and newer (ERMS) hardware, so far we've been going with just a single flavor of these two functions, and oddly enough with ones not consistent with one another. Using plain memcpy() / memset() on MMIO (video frame buffer) is generally okay, but the ERMS variant of memcpy() turned out to regress (boot) performance in a way easily visible to the human eye. Hence as a prerequisite step this series switches the frame buffer (and VGA) mapping to be write-combining independent of firmware arrangements (of MTRRs in particular). 1: x86: correct comment about alternatives ordering 2: x86: introduce ioremap_wc() 3: x86: re-work memset() 4: x86: re-work memcpy() 5: video/vesa: unmap frame buffer when relinquishing console 6: video/vesa: drop "vesa-mtrr" command line option 7: video/vesa: adjust (not just) command line option handling Side note: While strictly speaking the xen/drivers/video/ changes fall under REST maintainership, with that code getting built for x86 only I'm restricting Cc-s to x86 maintainers. Jan