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 B5164CA1005 for ; Tue, 2 Sep 2025 12:56:36 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.1106408.1457097 (Exim 4.92) (envelope-from ) id 1utQYm-0000hh-Ck; Tue, 02 Sep 2025 12:56:28 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 1106408.1457097; Tue, 02 Sep 2025 12:56:28 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1utQYm-0000ha-9W; Tue, 02 Sep 2025 12:56:28 +0000 Received: by outflank-mailman (input) for mailman id 1106408; Tue, 02 Sep 2025 12:56:27 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1utQYl-0000hN-4j for xen-devel@lists.xenproject.org; Tue, 02 Sep 2025 12:56:27 +0000 Received: from mail-ed1-x533.google.com (mail-ed1-x533.google.com [2a00:1450:4864:20::533]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 3b7ce92c-87fc-11f0-8dd7-1b34d833f44b; Tue, 02 Sep 2025 14:56:25 +0200 (CEST) Received: by mail-ed1-x533.google.com with SMTP id 4fb4d7f45d1cf-61a8c134533so9660449a12.3 for ; Tue, 02 Sep 2025 05:56:25 -0700 (PDT) Received: from [10.156.60.236] (ip-037-024-206-209.um08.pools.vodafone-ip.de. [37.24.206.209]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-61cfc4bbcc7sm9390400a12.24.2025.09.02.05.56.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 02 Sep 2025 05:56:24 -0700 (PDT) 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: 3b7ce92c-87fc-11f0-8dd7-1b34d833f44b DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1756817784; x=1757422584; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to; bh=cxEmf8jKtqP9DgLcpkszv1taQDwhXj+TB4X+KX4NdnU=; b=KiF0COKoduhEMf1zSi8a9EMNhmmMGs8lf7AWJMlgbObJ5rDQv6bNfczJqzJEKxSF7q 22aauSDFeWvFpmUGkWS+mFINXduvys9S8sqjikX60AMsk/J88i5KMoQS3ecqkikbcl3u VRG6U+L6jAnS2FO0yxvS9tuLiZXWGQHu3tEA1h8RCqPqB2cx/tkDfsLD9VnOcng2PH8D qIPUtrtiQap/hzEuvpGqjck5LaXpYby6joAypLT5kJ/u3f/NZvYKxuTx4+0R0E7p7LRt YzaIFdw8wW/4Q3jQ0jL+XLIJyMBRiWVWintk88pgfs02VxZae+dRbgD7jnVbbankY+nX XK8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756817784; x=1757422584; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=cxEmf8jKtqP9DgLcpkszv1taQDwhXj+TB4X+KX4NdnU=; b=ruO8Eq/qjtJJd4S6NriDbG7Q4qiZRIdHx2cv8A5PvsanZ/yT7JY6niOcaAG6F+3t/i iHZl0elOp+c9CLxTUdbJAIzWIWC6IREmaq6854G7LLKZiuKFFTCXAk/WA8n7DNgMy7xV Mp0vn97+JPz1bPgM+PVzuMrZJJgx77BjzOUqA2sor5oJTTfP/yTDrbP+dA80GoVgacan bOz8LYlekfgT/i6cmlWcRXfvNz5nHH51vJcHo4m7cmlMLVyBDN+xezV/SLyp9hk5gKgs 4j05g7gMtv5s/Ew5vqRWQym9mOh6NdaPG52VGm24i8YG7tpcWXnxQpRhfTxJhp0ppVLO jZ7w== X-Forwarded-Encrypted: i=1; AJvYcCXHr8z8I+340BBkUyMjp02FpGX5vDzx2O3EeXq7L7os7gtGagabMa2kBh9Vd6LdEVvfqVlwlRfNIeI=@lists.xenproject.org X-Gm-Message-State: AOJu0Yy4m8KJbRltcz+iRT9+iareEnTe1KskWzZ5WHwHwFgx/jgtF0lu BfCpWjmgv16KfwYoLUs4hhFePDH6avFg4H6O5WHCTpUn+i+srxYyJFgYfQLRCYKRKA== X-Gm-Gg: ASbGncv1/0nK3dzeMg5NoeUqNSo6J7AYNLrfQO+uGAuJhDDMkGzaMm6VDEOiMTneCYz hhfaXf6lKvGrsUp3uYWkK/uDCJu2PuYfBSpOAvbfvPXnyCdcJk/X8nfk9DdrpUKuSAKRv/qqp1F k6cI4Q3hztRhE9AKxlasOEh2qUUmbgiIqFvha11mTSuSsA7TLNtVev3jbrXkBAgdUwg4/DExLSN I+Xy79j9E/Zki/KhMN9YRgVeRCkB0YbF5xXhgo9767+mDFbUBdAx6X8TLKEtkmhoxLtJqV5QdJT djcXTuv3xXoUSCI69I7rqsLBJw7rXQPvxq2hTKjzpM/fEtICnXZpXaExhG1W4smFfkpKSXJo8eO +t5w8yqVdy9sXiWen3DjetVoVDyFAKLhGrPjisq3uF3aF+eysEm9vivStCy0hmVDCQ8jDA0tNyf 1NnVOLkUg= X-Google-Smtp-Source: AGHT+IEly4ATefmI7CxtKeh7/EbG28xcd3d0OaZ3FKNqBVqTgJqrdgOi232tbMO2kOSEZnLwF05zTw== X-Received: by 2002:a05:6402:40ce:b0:61c:c086:8092 with SMTP id 4fb4d7f45d1cf-61d26fd0c7emr11599428a12.23.1756817784349; Tue, 02 Sep 2025 05:56:24 -0700 (PDT) Message-ID: <8a1fa32f-e7fb-4879-8516-1ddca5367619@suse.com> Date: Tue, 2 Sep 2025 14:56:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: issue with dom0_pvh on Xen 4.20 To: Manuel Bouyer Cc: Andrew Cooper , xen-devel@lists.xenproject.org, Juergen Gross References: <68988b80-f642-4fcf-a624-49ad9fdd685c@citrix.com> <957429d8-ec8c-4327-b8fc-71fe9ddb2d33@suse.com> <7d0fc0eb-52a4-4478-8c1b-9a359513abdd@suse.com> Content-Language: en-US From: Jan Beulich Autocrypt: addr=jbeulich@suse.com; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 02.09.2025 14:54, Manuel Bouyer wrote: > On Tue, Sep 02, 2025 at 02:45:04PM +0200, Jan Beulich wrote: >>>> What puzzles me is that: >>>> >>>> - %cr2 is 0, so probably the first fault wasn't a page fault >>> >>> AFAIK it can't be as we're still in real mode >> >> It's protected mode, but with paging still off. >> >>>> - 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? >>> >>> No. RIP shouldn't end up there in any way. the assembly code is quite simple, >>> it's just a loop and I'm quite confident that we did enter the loop with >>> sane values >> >> Yet Jürgen has a point - entry point and what is being modified are on the >> same page (and despite paging still being off, you writing page tables here >> makes pages a relevant unit). Considering >> - entry point @ 0x20e4d0 >> - %ecx = 0xdfeb7 >> - %ebx = 0x20e260 >> the loop continuing a little further will overwrite the entry point code. >> And with the entry point not at an even (e.g page-aligned) address, other >> code (like the one here) could conceivably live immediately ahead of it. >> (Of course this overwriting may be intentional, but it looks suspicious in >> this context.) > > Indeed. Now the exact same kernel is booting fine with Xen 4.18 (and also > the same bootstrap is used for domU PVH which works with Xen 4.20). > I guess something changed in the way Xen sets up the dom0 kernel. Hence why Andrew asked for full logs of both boots, to put side by side. Jan