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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 A35AFC33C9E for ; Fri, 17 Jan 2020 03:46:38 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 0E1312082F for ; Fri, 17 Jan 2020 03:46:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ozlabs.org header.i=@ozlabs.org header.b="MRpG3pi7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0E1312082F Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47zRnR24mQzDqsK for ; Fri, 17 Jan 2020 14:46:35 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47zRkp3FYBzDqlY for ; Fri, 17 Jan 2020 14:44:18 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=ozlabs.org header.i=@ozlabs.org header.a=rsa-sha256 header.s=201707 header.b=MRpG3pi7; dkim-atps=neutral Received: by ozlabs.org (Postfix, from userid 1003) id 47zRkn4PZZz9sRd; Fri, 17 Jan 2020 14:44:17 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1579232657; bh=ltSUYl1RDYBIGn9bPmKjAqMNA4aASu38qTLJ2lZkEmE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MRpG3pi7GFi82Qba6Pzm7uB4nfP9Nr3XKcwo53umfhcl1ylDaP8aSeCiGvQLvrRNH 9UgQTp523GqjiRHNU3+3yCMjIWcfLD1WiZLF07pUHNnLn/tsgz61WJ5TWluBb48Iev Hs7nl4B06xm282BE7/4zRUzj+CuQH4oAIHMKH6Q+zNRlghHbP3dYkMibYMIS54/r/P qhOUwkUNS3cIL2DohqyqXf47gYURRje8UIo5txvYuite4BHSqq38N+HBxswvrZVT9P WF8rlCMO6t1soIhmpiYHWdE/uEJL7VWuccRAMzb4Ta8Yl1vJyaRV/wBqK+lOR8lqfm I9gcUrjyuB5Pg== Date: Fri, 17 Jan 2020 14:43:54 +1100 From: Paul Mackerras To: Jordan Niethe Subject: Re: [PATCH v3] powerpc/mm: Remove kvm radix prefetch workaround for Power9 DD2.2 Message-ID: <20200117034354.GA31793@blackberry> References: <20191206031722.25781-1-jniethe5@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191206031722.25781-1-jniethe5@gmail.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: oohall@gmail.com, linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Dec 06, 2019 at 02:17:22PM +1100, Jordan Niethe wrote: > Commit a25bd72badfa ("powerpc/mm/radix: Workaround prefetch issue with > KVM") introduced a number of workarounds as coming out of a guest with > the mmu enabled would make the cpu would start running in hypervisor > state with the PID value from the guest. The cpu will then start > prefetching for the hypervisor with that PID value. > > In Power9 DD2.2 the cpu behaviour was modified to fix this. When > accessing Quadrant 0 in hypervisor mode with LPID != 0 prefetching will > not be performed. This means that we can get rid of the workarounds for > Power9 DD2.2 and later revisions. Add a new cpu feature > CPU_FTR_P9_RADIX_PREFETCH_BUG to indicate if the workarounds are needed. > > Signed-off-by: Jordan Niethe Acked-by: Paul Mackerras