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 DABDCC54FD0 for ; Mon, 27 Apr 2020 10:13:10 +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 9F6E3206E9 for ; Mon, 27 Apr 2020 10:13:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="paeT7ovT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F6E3206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jT0kq-0008ET-2u; Mon, 27 Apr 2020 10:12:48 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jT0ko-0008EO-Nm for xen-devel@lists.xenproject.org; Mon, 27 Apr 2020 10:12:46 +0000 X-Inumbo-ID: a3ee47ba-886f-11ea-9887-bc764e2007e4 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id a3ee47ba-886f-11ea-9887-bc764e2007e4; Mon, 27 Apr 2020 10:12:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=In-Reply-To:Content-Transfer-Encoding:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: 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=ikXeH5pqkWd9nkgispYOKOu5xKy4tP8PB0LrN6CIN/M=; b=paeT7ovTS2gkLQosjxIwZmw7VE JXp/LlvIh+bmeiBBOPVq55p6FeptftX/QUbvZFyJG0RzJv3wQ+gxCYT6e0uU2JDPhIEbSjwt0slVv ryEVq0ZZxIApTU3+g0ATWn1VMITytz+dObtA3MhL76XkmA7X1f/pUxOlUAWN3rUDgbxY=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jT0ki-0003iC-9I; Mon, 27 Apr 2020 10:12:40 +0000 Received: from 44.142.6.51.dyn.plus.net ([51.6.142.44] helo=debian) by xenbits.xenproject.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jT0kh-0005Ee-Vi; Mon, 27 Apr 2020 10:12:40 +0000 Date: Mon, 27 Apr 2020 11:12:35 +0100 From: Wei Liu To: Jan Beulich Subject: Re: [PATCH v11 1/3] x86/tlb: introduce a flush HVM ASIDs flag Message-ID: <20200427101235.6xko3lvt3qajo64m@debian> References: <20200423145611.55378-1-roger.pau@citrix.com> <20200423145611.55378-2-roger.pau@citrix.com> <59e48d80-8ce1-3f3d-c07e-5117adea272a@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <59e48d80-8ce1-3f3d-c07e-5117adea272a@suse.com> User-Agent: NeoMutt/20180716 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Wei Liu , Andrew Cooper , Tim Deegan , George Dunlap , xen-devel@lists.xenproject.org, Roger Pau Monne Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On Thu, Apr 23, 2020 at 06:33:49PM +0200, Jan Beulich wrote: > On 23.04.2020 16:56, Roger Pau Monne wrote: > > Introduce a specific flag to request a HVM guest linear TLB flush, > > which is an ASID/VPID tickle that forces a guest linear to guest > > physical TLB flush for all HVM guests. > > > > This was previously unconditionally done in each pre_flush call, but > > that's not required: HVM guests not using shadow don't require linear > > TLB flushes as Xen doesn't modify the pages tables the guest runs on > > in that case (ie: when using HAP). Note that shadow paging code > > already takes care of issuing the necessary flushes when the shadow > > page tables are modified. > > > > In order to keep the previous behavior modify all shadow code TLB > > flushes to also flush the guest linear to physical TLB if the guest is > > HVM. I haven't looked at each specific shadow code TLB flush in order > > to figure out whether it actually requires a guest TLB flush or not, > > so there might be room for improvement in that regard. > > > > Also perform ASID/VPID flushes when modifying the p2m tables as it's a > > requirement for AMD hardware. Finally keep the flush in > > switch_cr3_cr4, as it's not clear whether code could rely on > > switch_cr3_cr4 also performing a guest linear TLB flush. A following > > patch can remove the ASID/VPID tickle from switch_cr3_cr4 if found to > > not be necessary. > > > > Signed-off-by: Roger Pau Monné > > Reviewed-by: Jan Beulich > Tim, ICYMI, this patch needs your ack. Wei.