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X-CSE-ConnectionGUID: TiICZdqfRbeSGb/0hJhmVw== X-CSE-MsgGUID: ihPokDuEQQCC+WjkztduCw== X-IronPort-AV: E=McAfee;i="6800,10657,11569"; a="72639641" X-IronPort-AV: E=Sophos;i="6.18,305,1751266800"; d="scan'208";a="72639641" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2025 14:32:38 -0700 X-CSE-ConnectionGUID: LdDEmxZYQv2nMcqOOnECDw== X-CSE-MsgGUID: xt124RSNQku2HvxNZX1OyQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.18,305,1751266800"; d="scan'208";a="178209425" Received: from ray2.jf.intel.com (HELO [10.24.81.144]) ([10.24.81.144]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2025 14:32:36 -0700 Message-ID: <74a390a1-42a7-4e6b-a76a-f88f49323c93@intel.com> Date: Tue, 30 Sep 2025 14:32:35 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/7] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum To: Vishal Annapurve , Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, bp@alien8.de, tglx@linutronix.de, peterz@infradead.org, mingo@redhat.com, hpa@zytor.com, thomas.lendacky@amd.com, x86@kernel.org, kas@kernel.org, rick.p.edgecombe@intel.com, dwmw@amazon.co.uk, kai.huang@intel.com, seanjc@google.com, reinette.chatre@intel.com, isaku.yamahata@intel.com, dan.j.williams@intel.com, ashish.kalra@amd.com, nik.borisov@suse.com, chao.gao@intel.com, sagis@google.com, farrah.chen@intel.com, Binbin Wu References: <20250901160930.1785244-1-pbonzini@redhat.com> <20250901160930.1785244-5-pbonzini@redhat.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/29/25 18:38, Vishal Annapurve wrote: >> On those platforms, the old kernel must reset TDX private memory before >> jumping to the new kernel, otherwise the new kernel may see unexpected >> machine check. Currently the kernel doesn't track which page is a TDX >> private page. For simplicity just fail kexec/kdump for those platforms. > Google has a usecase that needs host kdump support on SPR/EMR > platforms. Disabling kdump disables the host's ability to dump very > critical information on host crashes altogether. Is Intel working on > enabling kdump support for platforms with the erratum? Nope. Any workarounds are going to be slow and probably imperfect. That's not a great match for kdump. I'm perfectly happy waiting for fixed hardware from what I've seen.