From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (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 91FD426E719 for ; Thu, 23 Oct 2025 20:29:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761251358; cv=none; b=ntrz3WAnodxk5h7vg6XPN/rxD9duGIztzvhTYNngXDINSt+sIzvxopYR4jMbKFUVP2vPT3puZQm+acYrS14lnGXvIftbCBfKev1txyZv2AoyIHbqbCwRxusbeeM7LR24FfYaMKzUsDiNcoeSQzG6ScIRtqYzb6NfpiDssw9cMDI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761251358; c=relaxed/simple; bh=1uR/1ye8/P8gFSnT3A5JnZHbdvRQfierQcZ8jqoDSxI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TzCOh1upOMdd7tXXttfEPSeXc08qKcUr5D3ukyGWjyEAj1JswDqbfq8AMwwzYg0WZ4R6alyVBqpoC8YDwoLgsKUydLLt6D7HWKCCxMvJaG+aX+jyZR8E8a1giRn6WRnunp0AN1zPeEmukfCpm1m2pF6I9t99jpJ4QtxHGBNTW/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=HbqrjNJ3; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="HbqrjNJ3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1761251356; x=1792787356; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=1uR/1ye8/P8gFSnT3A5JnZHbdvRQfierQcZ8jqoDSxI=; b=HbqrjNJ3j4YF2ccfH/xsqK2lsLg+6LlXEkOrwUL18JdvMDJLwyprk8D/ mJeWyyJCRH8vhZ5HxqrRGD4A0Hs0JmqmmqA4N1Mj8TsCMdSVLiLREvTkC 73nzL+rlZn1bSXYO1qZuejf9QPh4CQeA+SkV7V7tWKW0lhdx5ZNGypZTM QREjEZktcZ7PyTGVFtQltFMEGTAE4TKSJHfUzbGd9qNEgQnxlvb1OcCYZ PwYf380EPyuKauq/1YSgx7EXIEy0fjjb7OQ4pO+4o9+2LBZoqidh5Vl8h dryGqkBsyZSskQK+5dC8Q7zsBKGCl7gFpuVmiak6YWmDG9QzYJK7R+IL2 g==; X-CSE-ConnectionGUID: e6pWU346QYqHPY6Qn0W8Vg== X-CSE-MsgGUID: w5FnkPkaTwaUXRtTqLM+LQ== X-IronPort-AV: E=McAfee;i="6800,10657,11586"; a="74553431" X-IronPort-AV: E=Sophos;i="6.19,250,1754982000"; d="scan'208";a="74553431" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2025 13:29:15 -0700 X-CSE-ConnectionGUID: T2mEtrDRSHKWqu/suny4JA== X-CSE-MsgGUID: P3xaxXEbQKe7VHD2YxkqNA== X-ExtLoop1: 1 Received: from tfalcon-desk.amr.corp.intel.com (HELO [10.125.108.251]) ([10.125.108.251]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2025 13:29:14 -0700 Message-ID: <6bd76106-339f-4204-a418-738b7ee545ab@intel.com> Date: Thu, 23 Oct 2025 13:29:13 -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 v2 1/1] x86/boot/compressed: Fix avoiding memmap in physical KASLR To: Michal Clapinski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Chris Li , x86@kernel.org Cc: "H. Peter Anvin" , Ard Biesheuvel , Dan Williams , Pasha Tatashin , linux-kernel@vger.kernel.org References: <20251022233743.1134103-1-mclapinski@google.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <20251022233743.1134103-1-mclapinski@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/22/25 16:37, Michal Clapinski wrote: ... > But it would not disable physical KASLR for: > memmap=1G!4G memmap=1G!5G memmap=1G!6G memmap=1G!7G memmap=1G!8G > since the whole function would be called 5 times and the last `if` > would never trigger. I'm missing something about how this works. The: static int i; is static so should be keeping state across function calls. For the purposes of checking 'i', why does it matter if the function is called one time with 5 arguments or 5 times with 1? Doesn't 'i' end up at the same value either way?