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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 93043E748F9 for ; Mon, 2 Oct 2023 16:44:58 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.611744.951280 (Exim 4.92) (envelope-from ) id 1qnM2K-0007jB-71; Mon, 02 Oct 2023 16:44:48 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 611744.951280; Mon, 02 Oct 2023 16:44:48 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnM2K-0007j4-2y; Mon, 02 Oct 2023 16:44:48 +0000 Received: by outflank-mailman (input) for mailman id 611744; Mon, 02 Oct 2023 16:44:46 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnM2I-0007iw-PI for xen-devel@lists.xenproject.org; Mon, 02 Oct 2023 16:44:46 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnM2I-00034v-Kr; Mon, 02 Oct 2023 16:44:46 +0000 Received: from gw1.octic.net ([88.97.20.152] helo=[10.0.1.240]) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1qnM2I-0000x6-FL; Mon, 02 Oct 2023 16:44:46 +0000 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" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID; bh=BI2XCv9MAPcpY+u4KjHORFQhrCboxdHz8tsWzDFOX60=; b=EN6u0gQM760Ij0zWna+KqA2FID 4CKoXv+6fWiBaphNxHxDjb+7Hwa3qBcgP2wIuXqAOekArAR966X80tgZnpRTcqO7X/ZofbFB/rkHW o9I+1Wz9D453fImJkxU/fDvMILQu/cm3axFnoqgeGaMmaTgW9Ocpc5t3iXtTqlalBqrQ=; Message-ID: <8c8d3e61-ba9d-4bd2-b5ea-17c2a76edd4e@xen.org> Date: Mon, 2 Oct 2023 17:44:45 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 09/10] x86: introduce GADDR based secondary time area registration alternative Content-Language: en-GB To: Roger Pau Monne , xen-devel@lists.xenproject.org, henry.wang@arm.com Cc: Jan Beulich , Andrew Cooper , Wei Liu , George Dunlap , Stefano Stabellini References: <20231002151127.71020-1-roger.pau@citrix.com> <20231002151127.71020-10-roger.pau@citrix.com> From: Julien Grall In-Reply-To: <20231002151127.71020-10-roger.pau@citrix.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, On 02/10/2023 16:11, Roger Pau Monne wrote: > From: Jan Beulich > > The registration by virtual/linear address has downsides: The access is > expensive for HVM/PVH domains. Furthermore for 64-bit PV domains the area > is inaccessible (and hence cannot be updated by Xen) when in guest-user > mode. > > Introduce a new vCPU operation allowing to register the secondary time > area by guest-physical address. > > An at least theoretical downside to using physically registered areas is > that PV then won't see dirty (and perhaps also accessed) bits set in its > respective page table entries. > > Signed-off-by: Jan Beulich > Reviewed-by: Roger Pau Monné For the small change in include/public/vcpu.h: Acked-by: Julien Grall Cheers,-- Julien Grall