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X-CSE-ConnectionGUID: YZcmEtbQQruhYmWpfws04Q== X-CSE-MsgGUID: jL2El2qOSm+jQx1qpfrKfQ== X-IronPort-AV: E=McAfee;i="6800,10657,11888"; a="88286795" X-IronPort-AV: E=Sophos;i="6.25,247,1779174000"; d="scan'208";a="88286795" 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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260827_111702_697610_97B9AE6A X-CRM114-Status: UNSURE ( 9.35 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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?