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 07EEECC6B0E for ; Tue, 13 Oct 2026 15:09:08 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.1447997.1663962 (Exim 4.92) (envelope-from ) id 1xGe7X-0004Fj-Gj; Tue, 13 Oct 2026 15:08:51 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 1447997.1663962; Tue, 13 Oct 2026 15:08:51 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1xGe7X-0004Fc-D3; Tue, 13 Oct 2026 15:08:51 +0000 Received: by outflank-mailman (input) for mailman id 1447997; Tue, 13 Oct 2026 15:08:49 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1xGe7V-0004ER-NY for xen-devel@lists.xenproject.org; Tue, 13 Oct 2026 15:08:49 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.98.2) (envelope-from ) id 1xGe7V-00000003Qvw-2d6l; Tue, 13 Oct 2026 15:08:49 +0000 Received: from 224.pool85-54-217.dynamic.orange.es ([85.54.217.224] helo=localhost) by xenbits.xenproject.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1xGe7U-00000002NA6-2fym; Tue, 13 Oct 2026 15:08:49 +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=xenproject.org; s=20200302mail; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=zrMIdH8hBmD1+odGiJwmQINQWdwA3ihIbKHe38IxbyU=; b=Q0bsAVvztm0x6B88FBmc5FntT4 zP0RuHGU5dZfwuRbm8rHa9XhJqWZijqlEDNVMvG2tIrRcOLAyixA48CIqk4Zf/A7efUYCyyLR3hfH Qjd694sqDfBU2smZW7uy/9z3yMBpRchdi51sBp7bajHvK4N7pq3hTMQbqWVA8T9HQI/o=; Date: Tue, 13 Oct 2026 17:08:46 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Jan Beulich Cc: "xen-devel@lists.xenproject.org" , Andrew Cooper , Teddy Astie Subject: Re: [PATCH 06/15] x86/PVH: keep a copy of Dom0's initial E820 map Message-ID: References: <1b4c2bb4-118d-497c-8d7d-f3824fd61a73@suse.com> <575ec1bc-764c-4016-a584-a79e57817d9a@suse.com> <5756a0b2-9480-4f31-ab0a-e23fd0ee080b@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5756a0b2-9480-4f31-ab0a-e23fd0ee080b@suse.com> On Tue, Oct 13, 2026 at 04:53:11PM +0200, Jan Beulich wrote: > On 13.10.2026 15:48, Roger Pau Monné wrote: > > On Mon, Oct 12, 2026 at 10:21:55AM +0200, Jan Beulich wrote: > >> pvh_populate_p2m() needs to populate RAM according to the initial map > >> established, prior to any stealing by pvh_steal_ram(). Subsequently the > >> invocations of those functions will (need to) move ahead of > >> pvh_populate_p2m(), so what to act on is no longer Dom0's memory map at > >> the time of invocation. > > > > But (most of?) the uses of pvh_steal_ram() expect to access the stolen > > RAM, and hence using pvh_steal_ram() ahead of pvh_populate_p2m() is > > not a present use-case? > > > > I assume you have a further use-case for pvh_steal_ram() that wants to > > steal a range before it's populated, which might be worth mentioning > > here, to add a bit more context? > > I thought that I'm saying just that already with "Subsequently ...". All > that logic needs splitting: Obtain a range ahead of populating, access > the range only afterwards. OK, it wasn't obviously clear from the message. I would possibly explicitly mention that it's just the allocation that's moved ahead, the access must be kept after pvh_populate_p2m(). > >> @@ -1389,6 +1395,15 @@ int __init dom0_construct_pvh(const stru > >> > >> iommu_hwdom_init(d); > >> > >> + nr_orig_e820 = d->arch.nr_e820; > >> + orig_e820 = xvmalloc_array(struct e820entry, nr_orig_e820); > >> + if ( !orig_e820 ) > >> + { > >> + printk("No memory for copy of E820 map (%u entries)\n", nr_orig_e820); > > > > For some of the printks during dom0 PVH construction we already print > > the domain (%pd), and I think it would be good to print it here also. > > Some not-yet-upstream uses (hyperlaunch) create several domains using > > this logic, it would be good to easily spot which domain triggered the > > errors. > > Can do, sure. That'll be a little inconsistent then for a while; maybe > I should add a patch adjusting all printk()s I didn't otherwise touch. It's kind of inconsistent already, see for example the messages at the top of dom0_construct_pvh(). I won't request that you fix the existing ones, but it would be better if new additions print the domain as part of the message. Thanks, Roger.