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 8F0F9CA1005 for ; Tue, 2 Sep 2025 13:42:22 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.1106514.1457177 (Exim 4.92) (envelope-from ) id 1utRGs-0002mI-8G; Tue, 02 Sep 2025 13:42:02 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 1106514.1457177; Tue, 02 Sep 2025 13:42:02 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1utRGs-0002mB-5R; Tue, 02 Sep 2025 13:42:02 +0000 Received: by outflank-mailman (input) for mailman id 1106514; Tue, 02 Sep 2025 13:42:01 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1utRGr-0002m5-Hk for xen-devel@lists.xenproject.org; Tue, 02 Sep 2025 13:42:01 +0000 Received: from isis.lip6.fr (isis.lip6.fr [2001:660:3302:283c::2]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 99a2c2a7-8802-11f0-8adc-4578a1afcccb; Tue, 02 Sep 2025 15:42:00 +0200 (CEST) Received: from asim.lip6.fr (asim.lip6.fr [132.227.86.2]) by isis.lip6.fr (8.18.1/8.16.1) with ESMTPS id 582Dfwix012114 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 2 Sep 2025 15:41:58 +0200 (CEST) Received: from armandeche.soc.lip6.fr (armandeche [132.227.63.133]) by asim.lip6.fr (8.15.2/8.15.2) with ESMTP id 582DfvRI021781; Tue, 2 Sep 2025 15:41:57 +0200 (MEST) Received: by armandeche.soc.lip6.fr (Postfix, from userid 20331) id E2F0E107F7; Tue, 2 Sep 2025 15:41:55 +0200 (CEST) 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" X-Inumbo-ID: 99a2c2a7-8802-11f0-8adc-4578a1afcccb Date: Tue, 2 Sep 2025 15:41:55 +0200 From: Manuel Bouyer To: Juergen Gross Cc: Andrew Cooper , xen-devel@lists.xenproject.org Subject: Re: issue with dom0_pvh on Xen 4.20 Message-ID: References: <68988b80-f642-4fcf-a624-49ad9fdd685c@citrix.com> <957429d8-ec8c-4327-b8fc-71fe9ddb2d33@suse.com> <2ad255ea-6c5e-4e9a-a821-db7449432399@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2ad255ea-6c5e-4e9a-a821-db7449432399@suse.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.4 (isis.lip6.fr [132.227.60.2]); Tue, 02 Sep 2025 15:41:58 +0200 (CEST) X-Scanned-By: MIMEDefang 3.4.1 on 132.227.60.2 On Tue, Sep 02, 2025 at 02:28:27PM +0200, Juergen Gross wrote: > > What puzzles me is that: > > > > - %cr2 is 0, so probably the first fault wasn't a page fault > > - RIP is %ebx + 8, so maybe the code was just clobbered by the loop? > > > > Could it be the code has been moved to this location, or is about to > > be moved away afterwards? > > And indeed: from the full boot log I can see: > > (XEN) virt_base = 0x0 > (XEN) elf_paddr_offset = 0x0 > (XEN) virt_offset = 0x0 > (XEN) virt_kstart = 0x200000 > (XEN) virt_kend = 0x17bab90 > (XEN) virt_entry = 0x20e4d0 > > So virt_kentry is very near to the RIP. thanks to this, I think I found the issue: with Xen 4.18, the kernel is started with ebx=17bb018; with 4.20 it's 100018. The bootstrap code assumes that the kernel is after the kernel, and the kernel symbol table. That seems to be no longer true with Xen 4.20 and a PVH dom0 (but probably still true in all other cases). I can deal with that, but with the new layout how do I get the end of the symbol table ? -- Manuel Bouyer NetBSD: 26 ans d'experience feront toujours la difference --