From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EDB1317D354; Sun, 27 Oct 2024 20:43:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.60.130.6 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730061820; cv=none; b=K29XfdJlGTlpd+Q7yG6ScjjZOGyRxprkCbg5NEeNiPY2BeArBJswvEt76BrwKkq9sdVkSEu8QaZXpFe6yZJV1UpXvaFRtQuHtu6pS8GUG3Xvo85Y9BubNc5SQXTWgW2hD9eYpvvHUflVTdK28qphBnKO7+rF9/MnrOq7mVMPSJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730061820; c=relaxed/simple; bh=rp/6cAX8qa+xCZdZgTWi88Vtnh8/7YSPavnh4VoQsqk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZxRL8Xe0Rh3wbNFwZMce9i1xXf/mI4SAl6oRImfeRNDLMaAaP09N2ugj1zQh+Sd7ymxMEVs3eOMGE2qTiBM/17nSDI7Q8CH4KWKbH4zVvXvlX9aEnNlSbsVJhzfF4Jo1Go7RUHtDcY+5XaFJw1AAmDuwD1lhMABtrOX2WgetYFs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com; spf=pass smtp.mailfrom=igalia.com; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b=KVAL0ILp; arc=none smtp.client-ip=178.60.130.6 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=igalia.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=igalia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="KVAL0ILp" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=1T8ILKm4ovamc8emWS1f1es99V1XULDZVRfssxb0X7s=; b=KVAL0ILpywa5Lo2ngSEr1c3Swm DDpKcW8zyC70vjJ9/IhyRe9C+5ZDWik1SQrbU1WtGwl/atuqIgj5PYCHAUslmNQ4Znm/JmHYUrDaX P/vq2n/ofMGyollaUkkuHe/Ur5VKw9q3M7QUX8FXbYCXSTM8ydjN4mBKuSXo+7gggGv55YTNpuu8n G1T1KtmnyqTyYofhsFJ2tLh5k8I+0Awt3f1LiqQnzUzxL/uoqKg3BvWH5htOfMfGRo3QEzbTJP/gz ornnrreC2W7RvNiM27PJ02HbGeImEDRORIOX3XRXVUImFLFEvWur7HImNV/FvZ4Z8z8xfsyS9cjDX 8/k5UzYw==; Received: from [189.79.117.125] (helo=[192.168.1.60]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1t5A6j-00FpyE-3s; Sun, 27 Oct 2024 21:43:29 +0100 Message-ID: Date: Sun, 27 Oct 2024 17:43:22 -0300 Precedence: bulk X-Mailing-List: linux-debuggers@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH V3] Documentation: Improve crash_kexec_post_notifiers description Content-Language: en-US To: Michael Kelley Cc: "bhe@redhat.com" , "kexec@lists.infradead.org" , "vgoyal@redhat.com" , "dyoung@redhat.com" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-debuggers@vger.kernel.org" , "stephen.s.brennan@oracle.com" , "horms@kernel.org" , "kernel@gpiccoli.net" , "kernel-dev@igalia.com" References: <20241025162042.905104-1-gpiccoli@igalia.com> From: "Guilherme G. Piccoli" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 27/10/2024 15:16, Michael Kelley wrote: > [...] >> crash_kexec_post_notifiers >> - Run kdump after running panic-notifiers and dumping >> - kmsg. This only for the users who doubt kdump always >> - succeeds in any situation. >> - Note that this also increases risks of kdump failure, >> - because some panic notifiers can make the crashed >> - kernel more unstable. >> + Only jump to kdump kernel after running the panic >> + notifiers and dumping kmsg. This option increases >> + the risks of a kdump failure, since some panic >> + notifiers can make the crashed kernel more unstable. >> + In configurations where kdump may not be reliable, >> + running the panic notifiers could allow collecting >> + more data on dmesg, like stack traces from other CPUS >> + or extra data dumped by panic_print. Note that some >> + configurations enable this option unconditionally, >> + like Hyper-V, PowerPC (fadump) and AMD SEV. > > This last line should be more specific and use "AMD SEV-SNP" instead of > just "AMD SEV". Commit 8ef979584ea8 that you mentioned above is > specific to SEV-SNP. > > There have been three versions of SEV functionality in AMD processors: > * SEV: the original guest VM encryption > * SEV-ES: SEV enhanced to cover register state as well > * SEV-SNP: SEV-ES plus Secure Nested Paging, which provides > functionality to address the Confidential Computing VM threat model > described in the Linux CoCo VM documentation. SEV-SNP processors are > AMD's product that is widely deployed for CoCo VMs in large public clouds. > > Just using "SEV" is somewhat ambiguous because it's not clear whether > it refers to the family of three SEV levels, or just the original guest VM > encryption. Since this case is clearly SEV-SNP only, being specific removes > the ambiguity. > > Michael Thanks a lot Michael, for the clarification. I've just sent a V4 updating that. Cheers, Guilherme