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Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1wxPyJ-00BOWn-2i; Fri, 21 Aug 2026 14:11:52 +0000 Date: Fri, 21 Aug 2026 07:11:47 -0700 From: Breno Leitao To: Pratyush Yadav Cc: Kiryl Shutsemau , Ard Biesheuvel , Ilias Apalodimas , Miaohe Lin , Naoya Horiguchi , Andrew Morton , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rmikey@meta.com, riel@surriel.com, kexec@lists.infradead.org, kernel-team@meta.com Subject: Re: [PATCH v2 2/6] efi: add the LINUX_EFI_POISONED_MEMORY configuration table Message-ID: References: <20260821-hwpoison-kho-v2-0-5743791e48e6@debian.org> <20260821-hwpoison-kho-v2-2-5743791e48e6@debian.org> <2vxz5x13znn1.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2vxz5x13znn1.fsf@kernel.org> X-Debian-User: leitao X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 303AA1C000C X-Stat-Signature: xnbrpcdas7nnaxa93umxj6rzi1mj7e8j X-Rspam-User: X-HE-Tag: 1787321523-806771 X-HE-Meta: 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 UoqTUFxr g/LHUsWhW4BefSvuvpN6ECLAUmPGOQLQ1CBdvG+1If+F/MgenboxyWP3/4ecfqHMp/qMJ7C+qWbczqAjME8kxdWnwKG7/RnIy9PE8lYCZtVZCPgmZeHsl8JLMtMFLwnC8euJkZVIRlEHE+9A/Z/KHsvojMxSINLKxgl7r8I9FM7sDcBoFLNTkHIHj7tcPokN7OjqmIYlPlAyeNap5c2ysRqh5Cg1OXHN2jcv+1snFggGa5utI4uoID6xdakXKltkuVXWAIb/UPCYudmOeaMiREgPYlJECGzGFgABbB3BbBZO9lMTHT+0uAzF0cZ8JSHHVugICbGa1YERKBNI4hOjZ2nAGBwtJqm7ePam+H1JTbF4U+mArjPhn2FQBl5+F/5saDKJQ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello Pratyush, On Fri, Aug 21, 2026 at 02:03:30PM +0200, Pratyush Yadav wrote: > >> +config EFI_POISONED_MEMORY > >> + bool "Carry hardware-poisoned pages across kexec" > >> + depends on EFI_STUB && MEMORY_FAILURE && 64BIT > >> + help > >> + Record page frames that are hardware-poisoned while this kernel runs > >> + into an EFI configuration table, and honor that table early on the > >> + next kernel so a kexec does not hand known-bad RAM back out. > >> + > >> + If unsure, say N. > >> + > > > > Do we want to make it conditional? Maybe just for everyone with EFI_STUB > > && MEMORY_FAILURE? > > +1. Each config we add is a decision someone has to make when compiling > the kernel. If they rely on the default, they will miss out on this > fairly useful feature. > > So, is there any downside to just doing this by default without any > config? The only downside I see is that this extra config table gets carved out of main memory for every MEMORY_FAILURE user. That is roughly 64 KiB per TiB of RAM, though, so maybe it is small enough to just enable by default?! Thanks for the review, --breno