From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (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 AF17825393E; Mon, 14 Apr 2025 14:19:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744640346; cv=none; b=eCoG/RLmAhLvtXHTxGZ68Px3ky61385KsvWiW9VaepqxzgAZ3A0lZMMMREg7vtiH8dGVMyzMi8JC2vpukuXJIUt5yNHFosvSbIpAEvUDdf7cnZFSZcR+HIRVb1fxWQQlLPamPHFu3AsUTpndlKKLIKXuUVPRD8MwdMX1CMoW4dE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744640346; c=relaxed/simple; bh=ZGi0N7JihKaxW674HLf7YHreoEQlnROr2bpo9jFgkBk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ACUrKkOerBbAr83hIlllfIo1GuaKqbl3Y/mmNaYIvyy24WkgY/aRSDK1X2XpQTdB1m6Pt8VnT3KCa1JGMq0Dl1CBhsHWH2qH+2EiI1s/ToYCHWFeY5pww1+JCo3uF0DvepMkaUpCLD0TYgaS/e7fuFg4ST283OCLcjanEIH+Yfw= 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=QUA7AlVw; arc=none smtp.client-ip=198.175.65.17 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="QUA7AlVw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1744640345; x=1776176345; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ZGi0N7JihKaxW674HLf7YHreoEQlnROr2bpo9jFgkBk=; b=QUA7AlVwIvji7X2oQkm5MguJFZFv6Ya9MvgWHHoBS8GjYXdD2qtgZ4OD dGksD8F5iix/KeoRnxu/Bg2HeY6EZ5GAOBB1VBMIYOcWkHJ4MObfbzewx EZUscpRcw7PkNVCBMgnNBYLGOIiVtLxR3Mef+zyl3Rst1BB/MuaxocTJI uVmMg1Wb3abEFoPJUwiMw1/5DBjN3JALFczxzY0+hjiqTJutfppogvJtY Lw3yyAQnR+Yoi4ZJHoNMgw4SCxJWmi7Jr6Mxba2arOV84DcWIV2fOwnAr uhIC4MML94sUbylrApSulhWz5EQc7ddB3Wk2WwSe/nJ+F1AjNokUdRc3c w==; X-CSE-ConnectionGUID: APLhuhZPRqmDiM+cvhAWGg== X-CSE-MsgGUID: wvrQDerTTKuIpcUfMoS8BQ== X-IronPort-AV: E=McAfee;i="6700,10204,11403"; a="46121904" X-IronPort-AV: E=Sophos;i="6.15,212,1739865600"; d="scan'208";a="46121904" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2025 07:19:04 -0700 X-CSE-ConnectionGUID: iD5gBL39T6eCeoWX3qQdxA== X-CSE-MsgGUID: vxa1uwQ/TFKThLpIjYggyQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,212,1739865600"; d="scan'208";a="130383960" Received: from johunt-mobl9.ger.corp.intel.com (HELO [10.124.222.39]) ([10.124.222.39]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2025 07:19:03 -0700 Message-ID: Date: Mon, 14 Apr 2025 07:19:02 -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: [tip: x86/urgent] x86/e820: Discard high memory that can't be addressed by 32-bit systems To: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org Cc: Arnd Bergmann , "Mike Rapoport (Microsoft)" , Ingo Molnar , Andy Shevchenko , Arnd Bergmann , Davide Ciminaghi , "H. Peter Anvin" , Linus Torvalds , Matthew Wilcox , Paolo Bonzini , Sean Christopherson , kvm@vger.kernel.org, x86@kernel.org References: <20250413080858.743221-1-rppt@kernel.org> <174453620439.31282.5525507256376485910.tip-bot2@tip-bot2> 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: <174453620439.31282.5525507256376485910.tip-bot2@tip-bot2> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/13/25 02:23, tip-bot2 for Mike Rapoport (Microsoft) wrote: > + /* > + * 32-bit systems are limited to 4BG of memory even with HIGHMEM and > + * to even less without it. > + * Discard memory after max_pfn - the actual limit detected at runtime. > + */ > + if (IS_ENABLED(CONFIG_X86_32)) > + memblock_remove(PFN_PHYS(max_pfn), -1); Mike, thanks for the quick fix! I did verify that this gets my silly test VM booting again. The patch obviously _works_. But in the case I was hitting max_pfn was set MAX_NONPAE_PFN. The unfortunate part about this hunk is that it's far away from the related warning: > if (max_pfn > MAX_NONPAE_PFN) { > max_pfn = MAX_NONPAE_PFN; > printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); > } and it's logically doing the same thing: truncating memory at MAX_NONPAE_PFN. How about we reuse 'MAX_NONPAE_PFN' like this: if (IS_ENABLED(CONFIG_X86_32)) memblock_remove(PFN_PHYS(MAX_NONPAE_PFN), -1); Would that make the connection more obvious?