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X-CSE-ConnectionGUID: LXrg6GWOTUSpXZWblBjNcg== X-CSE-MsgGUID: DrJ9prskQKiCi2jO14N+uQ== X-IronPort-AV: E=McAfee;i="6800,10657,11888"; a="88286792" X-IronPort-AV: E=Sophos;i="6.25,247,1779174000"; d="scan'208";a="88286792" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2026 11:17:00 -0700 X-CSE-ConnectionGUID: eQPmF8lcSF+SYQxndLuFCw== X-CSE-MsgGUID: uN+GdqPBSAqKphEQRxC5EQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,247,1779174000"; d="scan'208";a="272164505" Received: from smithj1-mobl2.amr.corp.intel.com (HELO [10.125.109.108]) ([10.125.109.108]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Aug 2026 11:16:59 -0700 Message-ID: <9ab4d7b8-6be9-4219-a410-ed26ae25c47e@intel.com> Date: Thu, 27 Aug 2026 11:17:01 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v9 13/25] mm: kpkeys: Introduce early page table allocator To: Kevin Brodsky , linux-hardening@vger.kernel.org Cc: Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linu Cherian , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?UTF-8?Q?Pierre-Cl=C3=A9ment_Tosi?= , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner References: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> <20260818-kpkeys-v9-13-743ad31b2c8f@arm.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 697151C0002 X-Stat-Signature: xa1pdmtyhn1rei7pu4yynfhffdcmkat6 X-Rspam-User: X-HE-Tag: 1787854621-938419 X-HE-Meta: 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 JWmo19wf AseS8htks6A5jg2r67/rfz1QapKopkss+gKfo+fWdKrrv9rKPXoaejAD5avayUiU4PIOd2ZOi7VqmEE7HVvEQuBQ4b6GnLtkrl/SbLS1qPJLL8GkT0juAjNrtszkOUoSE+qcTQ1mvDH/feMPoemXpid1Bn8iVLU71Qypqmlq8YT23fVgR5djNP2GBIeSIUJCIBtLKmg/+F9t2pNC7dhJ/1TzvueINsl8NhwQC Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/18/26 07:08, Kevin Brodsky wrote: > This patch addresses the second category: PTPs allocated via memblock. > Such PTPs are notably used to create the linear map. Protecting them as > soon as they are allocated would require modifying the linear map while > it is being created, which seems at best difficult. Instead, a > simple allocator is introduced, obtaining pages from memblock and > keeping track of all allocated ranges to set their pkey once it is > safe to do so. What makes setting a pkey on the memory "unsafe"? Is there something preventing just making access permissive during boot?