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=-8.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 18B5BC433DF for ; Fri, 16 Oct 2020 06:34:56 +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 8F476207C4 for ; Fri, 16 Oct 2020 06:34:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="HbMJv5Cc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F476207C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none 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.7778.20491 (Exim 4.92) (envelope-from ) id 1kTJJr-0005mB-Bo; Fri, 16 Oct 2020 06:34:27 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 7778.20491; Fri, 16 Oct 2020 06:34:27 +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" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kTJJr-0005m4-6o; Fri, 16 Oct 2020 06:34:27 +0000 Received: by outflank-mailman (input) for mailman id 7778; Fri, 16 Oct 2020 06:34:25 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kTJJp-0005ly-2l for xen-devel@lists.xenproject.org; Fri, 16 Oct 2020 06:34:25 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id ac51cd41-d605-47cc-94b0-057500150fd2; Fri, 16 Oct 2020 06:34:23 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5BB33AAB2; Fri, 16 Oct 2020 06:34:22 +0000 (UTC) Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kTJJp-0005ly-2l for xen-devel@lists.xenproject.org; Fri, 16 Oct 2020 06:34:25 +0000 X-Inumbo-ID: ac51cd41-d605-47cc-94b0-057500150fd2 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id ac51cd41-d605-47cc-94b0-057500150fd2; Fri, 16 Oct 2020 06:34:23 +0000 (UTC) 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=1602830062; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SBYcJbm6E2RUymANpskA8uW7qA08jhfAaNuFPo147lU=; b=HbMJv5Ccu9XcMMs1LKWXT7p394MbksH5RsyxwbngLpKmLK8j9nXA56E64KriFmhPe0g3Rq aRcIBJzHWTmU+1A7FzdoX4IPo9ZB90q92SZwyfobDKIgMNRENPgYthvg7Gpd6PtRZdyMRf WH+Uo+lpftFmWlLkyjPs7uik469HWJM= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5BB33AAB2; Fri, 16 Oct 2020 06:34:22 +0000 (UTC) Subject: Re: [PATCH v2] hvmloader: flip "ACPI data" to "ACPI NVS" type for ACPI table region To: Igor Druzhinin Cc: xen-devel@lists.xenproject.org, andrew.cooper3@citrix.com, roger.pau@citrix.com, wl@xen.org, iwj@xenproject.org References: <1602808763-22396-1-git-send-email-igor.druzhinin@citrix.com> From: Jan Beulich Message-ID: Date: Fri, 16 Oct 2020 08:34:24 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <1602808763-22396-1-git-send-email-igor.druzhinin@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 16.10.2020 02:39, Igor Druzhinin wrote: > ACPI specification contains statements describing memory marked with regular > "ACPI data" type as reclaimable by the guest. Although the guest shouldn't > really do it if it wants kexec or similar functionality to work, there > could still be ambiguities in treating these regions as potentially regular > RAM. > > One such example is SeaBIOS which currently reports "ACPI data" regions as > RAM to the guest in its e801 call. Which it might have the right to do as any > user of this is expected to be ACPI unaware. But a QEMU bootloader later seems > to ignore that fact and is instead using e801 to find a place for initrd which > causes the tables to be erased. While arguably QEMU bootloader or SeaBIOS need > to be fixed / improved here, that is just one example of the potential problems > from using a reclaimable memory type. > > Flip the type to "ACPI NVS" which doesn't have this ambiguity in it and is > described by the spec as non-reclaimable (so cannot ever be treated like RAM). > > Signed-off-by: Igor Druzhinin Acked-by: Jan Beulich