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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C390C87FD3 for ; Fri, 1 Aug 2025 00:01:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA4BE8E0002; Thu, 31 Jul 2025 20:01:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B4EA98E0001; Thu, 31 Jul 2025 20:01:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A16358E0002; Thu, 31 Jul 2025 20:01:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 8D0C68E0001 for ; Thu, 31 Jul 2025 20:01:51 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 3E8F11148A2 for ; Fri, 1 Aug 2025 00:01:51 +0000 (UTC) X-FDA: 83726235222.07.90C7400 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.20]) by imf02.hostedemail.com (Postfix) with ESMTP id D79CC80002 for ; Fri, 1 Aug 2025 00:01:48 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=bNHy4J7c; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf02.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.20 as permitted sender) smtp.mailfrom=dave.hansen@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1754006509; a=rsa-sha256; cv=none; b=x0QYm9l81fG6h2ZRyaV+Jrvp2dXdOrbIH8jqhsBrnCl0d3Q8fbfgUXssNM37NHtrveR5wP CFc5wVI+eIYRK0Tn24kFCMAWoPuZMbFefAgmOIhMvEjZDfgSRO1Mo+ANp1kiGfnnim/qUs cC0A8/5Q3DRaMyAK9Rh/mkAAPVEi/D4= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=bNHy4J7c; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf02.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.20 as permitted sender) smtp.mailfrom=dave.hansen@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754006509; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ySpoEGAAgT62IgZjG7h3TunT6qx8sRaYDgbb77t0uVk=; b=FBe30/FYS8xslWeb0kZSNU4S5IBfWtU9K29fu2K+QXaTi3jFAjQhFxNiDo5Va3en4+hl5G MxwFBQ36qbTrCmIUhA+qA042DAe2YOmFv4sjCGKKrd49htINvfRvYezvxVGabt/iihH2Nx Vs+rfXj+J51HOj42E0oaBLZRNoy3Qyg= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1754006509; x=1785542509; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=1eMiJ7biR+ze6mCfiSgA6AfqPnXORCkRF7qJ0xrnJ/Y=; b=bNHy4J7cokFRCGB+rLw81Bn4tPw4L06/dUcfvLJVmn43ihfU7pCOTcmN jDdjaSUm6/ujm5avtssK7fVmjeLot6t6qSZqVFGayQ4ixcwT+2DZzRhHj yEhH8DftKqC8kzfJlm+jFqnXE9WrovCVaaiPfCAcqTBLbaPjRiqD/J5/u WgNCrylUkw2MIMDBjcBbLkY/dG1GuT2EoZJQZgRNNxz6rlhtFWKMBygFK KTaASGYWxr1PjBKKND3o9lcOhKgQczvf9yM9elM8MzIvqGRS5zezYPl7T wStvvDznhLJwVQ4rIv9pfLKpH8rmMP0+/eRmIBVFQnZKy6c3yjHTXO3fE w==; X-CSE-ConnectionGUID: RA6XDHwJR+mRX92RyhRvzA== X-CSE-MsgGUID: AIj0OyjUQR20Aetp25ebLg== X-IronPort-AV: E=McAfee;i="6800,10657,11508"; a="56043753" X-IronPort-AV: E=Sophos;i="6.17,255,1747724400"; d="scan'208";a="56043753" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa112.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2025 17:01:41 -0700 X-CSE-ConnectionGUID: KF8Fav4TTe+6FIeh6in4Qg== X-CSE-MsgGUID: QxlgbGzmTCClfHyUq4ajLQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.17,255,1747724400"; d="scan'208";a="194235490" Received: from gabaabhi-mobl2.amr.corp.intel.com (HELO [10.125.109.228]) ([10.125.109.228]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2025 17:01:39 -0700 Message-ID: <6e768f25-3a1c-48b9-bc53-56877a556a83@intel.com> Date: Thu, 31 Jul 2025 17:01:37 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHv9 04/16] x86/cpu: Defer CR pinning setup until core initcall To: Sohil Mehta , Thomas Gleixner , Dave Hansen , Kees Cook Cc: Jonathan Corbet , Ingo Molnar , Pawan Gupta , Daniel Sneddon , Kai Huang , Sandipan Das , Breno Leitao , Rick Edgecombe , Alexei Starovoitov , Hou Tao , Juergen Gross , Vegard Nossum , Eric Biggers , Jason Gunthorpe , "Masami Hiramatsu (Google)" , Andrew Morton , Luis Chamberlain , Yuntao Wang , Rasmus Villemoes , Christophe Leroy , Tejun Heo , Changbin Du , Huang Shijie , Geert Uytterhoeven , Namhyung Kim , Arnaldo Carvalho de Melo , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org, "Kirill A. Shutemov" , "Kirill A. Shutemov" , Andy Lutomirski , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , Xin Li , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , Tony Luck , Alexey Kardashevskiy , Alexander Shishkin , X86-kernel References: <20250707080317.3791624-1-kirill.shutemov@linux.intel.com> <20250707080317.3791624-5-kirill.shutemov@linux.intel.com> <6075af69-299f-43d2-a3c8-353a2a3b7ee7@intel.com> <98a7a91b-3b46-4407-82a7-5f80443b7e00@intel.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: <98a7a91b-3b46-4407-82a7-5f80443b7e00@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: D79CC80002 X-Stat-Signature: 4zhiqtdw4k7dzeqrgu349dkwtuozw9wn X-HE-Tag: 1754006508-467827 X-HE-Meta: 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 wpu5Tc5v Euxl5U9Uh/chUMkvU++WEqGJlQYN1j8bZkS5NoSV4tfLVp09i+4dNSdt832HslTjGAYo1SAG+/JMj+lwfl8lt8bo6WDnrx49j19rHCQ9gFXPuxwIt9UOI4eyMVolJk5jfCo4VsAgPRANyVibTUjIj7vvejNekJLqihwS8bhSXP0jlXHySXTV3NfQk2sZ1z8G2RzwmDjb143dRW4/M71Yv87KDJlQ8/MBXZZzZK3KucNHgPS7BdXhionvFg412an1f0L+lMifK8iCAcAHXmhyAnw3/eg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/31/25 16:45, Sohil Mehta wrote: > On 7/9/2025 10:00 AM, Dave Hansen wrote: >> On 7/7/25 01:03, Kirill A. Shutemov wrote: >>> Instead of moving setup_cr_pinning() below efi_enter_virtual_mode() in >>> arch_cpu_finalize_init(), defer it until core initcall. >> What are the side effects of this move? Are there other benefits? What >> are the risks? >> > Picking this up from Kirill.. Reevaluating this, core_initcall() seems > too late for setup_cr_pinning(). > > We need to have CR pinning completed, and the associated static key > enabled before AP bring up. start_secondary()->cr4_init() depends on the > cr_pinning static key to initialize CR4 for APs. Sure, if you leave cr4_init() completely as-is. 'cr4_pinned_bits' should be set by the boot CPU. Secondary CPUs should also read 'cr4_pinned_bits' when setting up their own cr4's, unconditionally, independent of 'cr_pinning'. The thing I think we should change is the pinning _enforcement_. The easiest way to do that is to remove the static_branch_likely() in cr4_init() and then delay flipping the static branch until just before userspace starts. Basically, split up the: static void __init setup_cr_pinning(void) { cr4_pinned_bits = this_cpu_read(cpu_tlbstate.cr4) & cr4_pinned_mask; static_key_enable(&cr_pinning.key); } code into its two logical pieces: 1. Populate 'cr4_pinned_bits' from the boot CPU so the secondaries can use it 2. Enable the static key so pinning enforcement is enabled