From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 10A2033CEA7; Tue, 28 Oct 2025 17:49:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761673768; cv=none; b=oS3xE2qX58jdIbrCvPY2pGpu2FUPRax0Ngso1dgxqit6SPALK03dhHENEoBkahSGAWCYJk7iF4bJ5BnFjHlz7jla0t5ZOV67DZ0yy5Do9fCby2X3dLGuMnQYjuibXbcqwbAR+8/g6NgO6flAYHBoMOJ1bts5nYmhVTK1neCNvrM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761673768; c=relaxed/simple; bh=vunf56U5PcZ3/tDBjhpbxvdftWozMDKJ8pa5fyEIV7U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AvrytTCtOMQQRvxiDke2HWaNfbeFlCqalUg3N2YzXPyMAIdVV5UBX/zqaPwQl/FAYFWNcD3wIcmHbh9wOE5h5niML25U5XJqzAm8f/JpEn5UQ6adXq8CSNGvPfuqfhGeWj0N+GqD7DSUguYfm4/fiDoxeUOrh74StD2syv/Ife8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=quZnmOVL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="quZnmOVL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BFADC4CEE7; Tue, 28 Oct 2025 17:49:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761673767; bh=vunf56U5PcZ3/tDBjhpbxvdftWozMDKJ8pa5fyEIV7U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=quZnmOVLSlMynA7G0LD7XnOq1NqPcp5r79JIFcBz8EKFK1d0gm8QKnJ7z18nm6muU +YsJbMwC6CTTTTtyw0qQ7tmH50KR6UmvfNFS82UjWv1rg4g1qnrfks8aOTESFzmirs a5OltNN2bRbv43CHTl0pR5bT1mT53yig5ObrvZfZvV/qQaZt5CKnU/6osmBzuJC+13 SKgCQHSXbiwC8VtcZOxdtrVsPRgZr4HIJ6mv+WXaUoEOLo9W1z0CBPjdgGkSeiQQWd 5TM0xT0vAW5HWz+4ZbFydDr4ZldINipvbNCrLOmgwrD56+clANqaCS7bE0Pu4N5/Wd Y01nyrDTmdrEw== Date: Tue, 28 Oct 2025 13:49:26 -0400 From: Sasha Levin To: "Huang, Kai" Cc: "patches@lists.linux.dev" , "stable@vger.kernel.org" , "Gao, Chao" , "Edgecombe, Rick P" , "x86@kernel.org" , "dave.hansen@linux.intel.com" , "kas@kernel.org" , "Annapurve, Vishal" , "thuth@redhat.com" , "Hunter, Adrian" , "alexandre.f.demers@gmail.com" , "pbonzini@redhat.com" , "linux-coco@lists.linux.dev" , "Chen, Farrah" , "Yamahata, Isaku" , "kvm@vger.kernel.org" Subject: Re: [PATCH AUTOSEL 6.17] x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL Message-ID: References: <20251025160905.3857885-1-sashal@kernel.org> <20251025160905.3857885-328-sashal@kernel.org> <5f7a42b60c5cf1dba8f59c30d5d8f20a95545cf0.camel@intel.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5f7a42b60c5cf1dba8f59c30d5d8f20a95545cf0.camel@intel.com> On Sun, Oct 26, 2025 at 10:25:02PM +0000, Huang, Kai wrote: >On Sat, 2025-10-25 at 11:59 -0400, Sasha Levin wrote: >> From: Kai Huang >> >> [ Upstream commit 10df8607bf1a22249d21859f56eeb61e9a033313 ] >> >> >[...] > >> --- >> >> LLM Generated explanations, may be completely bogus: >> >> YES >> >> Why this fixes a real bug >> - TDX can leave dirty cachelines for private memory with different >> encryption attributes (C-bit aliases). If kexec interrupts a CPU >> during a SEAMCALL, its dirty private cachelines can later be flushed >> in the wrong order and silently corrupt the new kernel’s memory. >> Marking the CPU’s cache state as “incoherent” before executing >> SEAMCALL ensures kexec will WBINVD on that CPU and avoid corruption. > > >Hi, > >I don't think we should backport this for 6.17 stable. Kexec/kdump and >TDX are mutually exclusive in Kconfig in 6.17, therefore it's not possible >for TDX to impact kexec/kdump. > >This patch is part of the series which enables kexec/kdump together with >TDX in Kconfig (which landed in 6.18) and should not be backported alone. I'll drop it, thanks for the review! -- Thanks, Sasha