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Shutemov" To: Khalid Ali Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, corbet@lwn.net, luto@kernel.org, peterz@infradead.org, ardb@kernel.org, jan.kiszka@siemens.com, kbingham@kernel.org, michael.roth@amd.com, rick.p.edgecombe@intel.com, brijesh.singh@amd.com, sandipan.das@amd.com, jgross@suse.com, thomas.lendacky@amd.com, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv2 0/3] x86: Make 5-level paging support unconditional for x86-64 Message-ID: References: <20250516091534.3414310-1-kirill.shutemov@linux.intel.com> <20250624081400.2284-1-khaliidcaliy@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250624081400.2284-1-khaliidcaliy@gmail.com> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: DE3E014000F X-Stat-Signature: cxp4moiqudkt69wuh544oe6rpu5c8tgh X-Rspam-User: X-HE-Tag: 1750754993-409639 X-HE-Meta: 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 wFCXWN+k HfihXMaAuHgqRP2ywzG+T8sKdScJ4m03oq0DoCHZuvINOxc6Vc9xFKUyCmXYGBSPb5FUcl+mcc979F/m1cjScAyrbAPeyoNPR52RqqvsUDQm7bWjKhAnWJbCY5uqyGSd4cQBS7a3pMjuzjtSEAQmftprD3w== 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 Tue, Jun 24, 2025 at 08:11:15AM +0000, Khalid Ali wrote: > This will break x86_64 cpus that doesn't support 5-level paging. No, it won't. The patchset removes compile-time config option to disable 5-level paging. After tha patchset all kernels will be built with 5-level paging *support*. The actual paging mode is chosen at boot time based on machine capabilities and kernel command line. Older HW will boot in 4-level paging mode just fine. -- Kiryl Shutsemau / Kirill A. Shutemov