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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 69332C44501 for ; Tue, 14 Jul 2026 15:09:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5BC026B00DE; Tue, 14 Jul 2026 11:09:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 56BD26B00E5; Tue, 14 Jul 2026 11:09:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4339C6B00E6; Tue, 14 Jul 2026 11:09:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 186DC6B00DE for ; Tue, 14 Jul 2026 11:09:33 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id B2BDCC03ED for ; Tue, 14 Jul 2026 15:09:32 +0000 (UTC) X-FDA: 84987716184.27.B96596D Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) by imf16.hostedemail.com (Postfix) with ESMTP id C8A3518000F for ; Tue, 14 Jul 2026 15:09:29 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Zu45SdRD; spf=pass (imf16.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.15 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1784041770; 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=Go9xu294vQ/xZtWM33cFG/GQMdagVD3s+eiqGDNT+vo=; b=ChI6+4HdIXun5SHN7k4Cx2Qox5wQCo/g9EDCXn+KXYeFiURxejMEQk9fxMlus8JPU/05tc SVQIzSEHNkG3ILG81hHEWmPByze6rYVPsDruF/2mCq7BYtvIHdFj6EU+R/1DyyuU6phagE ZX1kUOClFNS0nUFRSeTVh/Irqzv7fPs= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Zu45SdRD; spf=pass (imf16.hostedemail.com: domain of dave.hansen@intel.com designates 198.175.65.15 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1784041770; b=aLcpqNhOF6MrN02aIcq25N2Wd7fdWm1JH9+lE2MImlINvgyB1r8tpxq2foFg/TASphGfS8 RXLmx5mrSYW23Yq9Rpyn6qVEeIAnO2WhH0R/B9r/nkbB4d+zGVw/LxCThXjEbEo8eGv741 OLMzkt68aVENiniUdlz7L58otnVeyss= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1784041770; x=1815577770; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=SHzp4jQz8eCvIdV8ejmgEgUpbyhbt03HpKcF+s/pm00=; b=Zu45SdRDUpTedchym1+CAPSKVM3OLxjH46haJbX64zEWibFBVyGX5Hyu irekaMSiTwRkBKD2bjw6BNloegglXhfKpw6twcKT5RfVXP9Grd4VvZRPZ GHvkEmtqWfW+G58L781tlaZQXx+3dTAIriSwcRbdKPBG81nA05KK63tO5 JPTjBEGJ0KdxZ+u91bkOibpnzkFKxC3T9R3VQkxFiK6kU6iIswLtCer5R w9Kp7hxavztIYEeLTzPH4+PhRAC/tt+/m+/vBqi8I3DKzJaDvY3SIHQkH kj2AQcddH3MZgpBSrB2At3+vZX9aWoEJUsQZToOT2m7RYvxzEQxRtKISr A==; X-CSE-ConnectionGUID: cqBNoTBvRL2yXyzCQGyCXA== X-CSE-MsgGUID: KCBAslVAQhusv/ZF/wRWZg== X-IronPort-AV: E=McAfee;i="6800,10657,11846"; a="88344357" X-IronPort-AV: E=Sophos;i="6.25,164,1779174000"; d="scan'208";a="88344357" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2026 08:09:28 -0700 X-CSE-ConnectionGUID: b6dfcSKcQJiv0EAhPLDFYA== X-CSE-MsgGUID: 47aAtZOESKmlSCqMXmHYjw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,164,1779174000"; d="scan'208";a="260186915" Received: from aschende-mobl.amr.corp.intel.com (HELO [10.125.108.120]) ([10.125.108.120]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2026 08:09:12 -0700 Message-ID: Date: Tue, 14 Jul 2026 08:09:15 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 12/22] x86/mm: use mm_is_kernel() for kernel mm checks To: Kevin Brodsky , linux-mm@kvack.org Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pasha Tatashin , Russell King , Catalin Marinas , Will Deacon , Ryan Roberts , linux-arm-kernel@lists.infradead.org, Huacai Chen , loongarch@lists.linux.dev, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Gerald Schaefer , linux-s390@vger.kernel.org, "David S. Miller" , Andreas Larsson , sparclinux@vger.kernel.org, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Ning Sun , x86@kernel.org, tboot-devel@lists.sourceforge.net, Ard Biesheuvel , Ilias Apalodimas , linux-efi@vger.kernel.org, Vishal Moola , Alistair Popple , "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org References: <20260714-remove_pgtable_cdtor-v1-0-44be8a7685d7@arm.com> <20260714-remove_pgtable_cdtor-v1-12-44be8a7685d7@arm.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: <20260714-remove_pgtable_cdtor-v1-12-44be8a7685d7@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C8A3518000F X-Stat-Signature: 9dp6opisy39qof4s4wtam7cxjcfdwqmj X-HE-Tag: 1784041769-728990 X-HE-Meta: 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 abc9MKb2 TOgBeILdMahgyxBeca8Zj6wD8doEVgHXbKK59Y5TR8LMbehxctr4LcyL3CseBthOI1owg+nAosa4p2RjGN7GkRFO4svTd0QrjWzpNw0bdJ0oHOynWC7hb3ZeXFiC3s0Mr/pQC1Ud/Z9HQljwbyviEoc69QMrDiJh3OymrkD5uroztKeZnJICoMNmkqlA2EPSGuyfI6A1z/FYbDUlIrHriA3FaR2r6MY4CkWuiCrUwS2vjkHSjrrUdUDqBmIpLxc2psZeN4+nmYog0U4Pd2OxoiQKx+ap/Q51g/o6fXFpJbS+9FxlmHhHu8f22UlvaUrhENOM3GX87mnBiBDw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/14/26 07:04, Kevin Brodsky wrote: ... > @@ -188,7 +188,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct tlb_state_shared, cpu_tlbstate_shared); > #define enter_lazy_tlb enter_lazy_tlb > static __always_inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) > { > - if (this_cpu_read(cpu_tlbstate.loaded_mm) == &init_mm) > + if (mm_is_kernel(this_cpu_read(cpu_tlbstate.loaded_mm))) > return; > > this_cpu_write(cpu_tlbstate_shared.is_lazy, true); This one makes me nervous, especially combined with the efi_mm changes later in the series. init_mm really is special. Before this patch, running on init_mm qualifies as being in lazy tlb mode. After this patch, efi_mm qualifies too. Is that OK? > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > index f32facdb3035..91d2a6f2ac5a 100644 > --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -168,7 +168,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) > bool failed = false; > gfp_t gfp = GFP_PGTABLE_USER; > > - if (mm == &init_mm) > + if (mm_is_kernel(mm)) > gfp &= ~__GFP_ACCOUNT; > gfp &= ~__GFP_HIGHMEM; This hunk is probably fine. > diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c > index 1023acadd8f8..5517cab8ad00 100644 > --- a/arch/x86/mm/tlb.c > +++ b/arch/x86/mm/tlb.c > @@ -594,7 +594,7 @@ void leave_mm(void) > * This needs to happen before any other sanity checks due to > * intel_idle's shenanigans. > */ > - if (loaded_mm == &init_mm) > + if (mm_is_kernel(loaded_mm)) > return; This one is almost *certainly* buggy. The efi_mm stuff uses leave_mm(). In fact, I think it's what's responsible for switching the hardware back over to use the init_mm page tables. If this check trips for init_mm, then the kernel will stay running on efi_mm when it's not intended to. Remember when I asked about whether there was going to be *a* kernel mm or lots? This is where it starts to matter. It's outside the diff context but the code here is basically: if (loaded_mm == &init_mm) return; switch_mm(NULL, &init_mm, NULL); So either all kernel mm's are equivalent or this code doesn't quite work. > /* Warn if we're not lazy. */ > @@ -855,7 +855,7 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, > * cpu_tlbstate_shared.is_lazy whether or not to send an IPI. > */ > if (IS_ENABLED(CONFIG_DEBUG_VM) && > - WARN_ON_ONCE(prev != &init_mm && !is_notrack_mm(prev) && > + WARN_ON_ONCE(!mm_is_kernel(prev) && !is_notrack_mm(prev) && > !cpumask_test_cpu(cpu, mm_cpumask(next)))) > cpumask_set_cpu(cpu, mm_cpumask(next)); > > @@ -932,7 +932,8 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, > * This way switch_mm() must see the new tlb_gen or > * flush_tlb_mm_range() must see the new loaded_mm, or both. > */ > - if (next != &init_mm && !cpumask_test_cpu(cpu, mm_cpumask(next))) > + if (!mm_is_kernel(next) && > + !cpumask_test_cpu(cpu, mm_cpumask(next))) > cpumask_set_cpu(cpu, mm_cpumask(next)); > else > smp_mb(); This one is interesting. It's basically saying that init_mm doesn't get mm_cpumask() updates. That makes sense since it has special TLB flushing rules. But what does this mean for efi_mm? Does it needs mm_cpumask() updates?