From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout2.mo534.mail-out.ovh.net (smtpout2.mo534.mail-out.ovh.net [51.210.94.141]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 065832D0C8A for ; Wed, 20 Aug 2025 10:17:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=51.210.94.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755685062; cv=none; b=hlhCOrLw6MXZ2Ds1sAB9vja1knSgvWkD/OZT0++y7QMGBLtFkZ2yX1ELAaL0Y7d+z9NRH0uHqS1dXnV2P5T1u/9MyVJ7FE6oF+MA4Jp/kF5eofq99l792+7aEVY3pWsFIy19h8UWguzAEvGd3oYmTsYWI/X4lmEvAm1SynDpPP4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755685062; c=relaxed/simple; bh=wciRcggMJi5GG6dGYY5OwzT4DYT1ab+VyI2ZUzHlmuU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VB1uLc9a+RrGsi+n/jlBV7cpJLyYnOEqG4yl4ZhT7BFlQsjb/VkrNGqp7VwQLUgj7ER43nWsgLI8184iUisopUiweJSlhpjOvIvUe4WKTm9ghTtcy3BV0RrBwHpnzjEPSNNU6edUYATL/JDp9fJto5j6QtvsHlyl4MzPQ8YoxrM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orca.pet; spf=pass smtp.mailfrom=orca.pet; dkim=pass (2048-bit key) header.d=orca.pet header.i=@orca.pet header.b=GiwykPBy; arc=none smtp.client-ip=51.210.94.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orca.pet Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=orca.pet Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=orca.pet header.i=@orca.pet header.b="GiwykPBy" Received: from director4.derp.mail-out.ovh.net (director4.derp.mail-out.ovh.net [79.137.60.37]) by mo534.mail-out.ovh.net (Postfix) with ESMTPS id 4c6MRf6CLSz6G6G; Wed, 20 Aug 2025 10:01:34 +0000 (UTC) Received: from director4.derp.mail-out.ovh.net (director4.derp.mail-out.ovh.net. [127.0.0.1]) by director4.derp.mail-out.ovh.net (inspect_sender_mail_agent) with SMTP for ; Wed, 20 Aug 2025 10:01:34 +0000 (UTC) Received: from mta11.priv.ovhmail-u1.ea.mail.ovh.net (unknown [10.110.54.141]) by director4.derp.mail-out.ovh.net (Postfix) with ESMTPS id 4c6MRd55hhz1xsB; Wed, 20 Aug 2025 10:01:33 +0000 (UTC) Received: from orca.pet (unknown [10.1.6.11]) by mta11.priv.ovhmail-u1.ea.mail.ovh.net (Postfix) with ESMTPSA id C8D619A32D3; Wed, 20 Aug 2025 10:01:30 +0000 (UTC) Authentication-Results:garm.ovh; auth=pass (GARM-111S005f0ff9220-28eb-43fd-b921-a03cb197dcb3, 616188B862BD6F9D24C783D7A018D61FF224AB69) smtp.auth=marcos@orca.pet X-OVh-ClientIp:79.117.22.109 Message-ID: <3db7d599-c2a7-4bec-94b1-4872649dde8d@orca.pet> Date: Wed, 20 Aug 2025 12:01:30 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] x86: add hintable NOPs emulation To: Borislav Petkov Cc: "Ahmed S. Darwish" , linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Brian Gerst , Uros Bizjak , Ard Biesheuvel , David Kaplan , Kees Cook , "Peter Zijlstra (Intel)" , Andrew Cooper , Oleg Nesterov , "Xin Li (Intel)" , Sabyrzhan Tasbolatov References: <20250820013452.495481-1-marcos@orca.pet> <2cd7b099-095d-405c-a7d9-b0f1f72184c2@orca.pet> <20250820094347.GDaKWY02hR3AAoT7la@fat_crate.local> <20250820095556.GEaKWbrMh24T7jTfBg@fat_crate.local> Content-Language: es-ES From: Marcos Del Sol Vives In-Reply-To: <20250820095556.GEaKWbrMh24T7jTfBg@fat_crate.local> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Ovh-Tracer-Id: 11312197839614072500 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeeffedrtdefgdduheektdejucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepkfffgggfuffvvehfhfgjtgfgsehtkeertddtvdejnecuhfhrohhmpeforghrtghoshcuffgvlhcuufholhcugghivhgvshcuoehmrghrtghoshesohhrtggrrdhpvghtqeenucggtffrrghtthgvrhhnpedtgedugfeiudfgkeduhfelgfejgfeuvdejffeiveegteejvddviefhiedujedvheenucfkphepuddvjedrtddrtddruddpjeelrdduudejrddvvddruddtleenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeduvdejrddtrddtrddupdhmrghilhhfrhhomhepmhgrrhgtohhssehorhgtrgdrphgvthdpnhgspghrtghpthhtohepudekpdhrtghpthhtohepsghpsegrlhhivghnkedruggvpdhrtghpthhtohepuggrvhhiugdrkhgrphhlrghnsegrmhgurdgtohhmpdhrtghpthhtoheprghnughrvgifrdgtohhophgvrhefsegtihhtrhhigidrtghomhdprhgtphhtthhopegsrhhgvghrshhtsehgmhgrihhlrdgtohhmpdhrtghpthhtohepshhnohhvihhtohhllhesghhmrghilhdrtghomhdprhgtphhtthhopehusghiiihjrghksehgmhgrihhlrdgtohhmpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgrug gvrggurdhorhhgpdhrtghpthhtoheprghruggssehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkvggvsheskhgvrhhnvghlrdhorhhg DKIM-Signature: a=rsa-sha256; bh=7ywoVmuDJMvVjQW9qj9BNxgunVZT9il645jXAJ7dNcE=; c=relaxed/relaxed; d=orca.pet; h=From; s=ovhmo-selector-1; t=1755684095; v=1; b=GiwykPBy1OzrZbKpCBLbIAsOnq0uww5YO/OnEXSrB5+UCxUUJdQHyg5K0yB5n5mBgsUhox2H k11zAb99+CqDD1SVkXC5fmAPi6DqdeuutWHEmMQ1A5m3Lsgdumwa8GU6sxXr8bk/3QZpIZAMjCy eNDpk8gF4O1cz+ZWGnRFaHY3khTjopT7utdC+FHEh9es4HSRuz9p9+CfpqweQtj2n57uHx8Z1f8 TApUGLSb/EsOaQ250Lk9uBuFXBiiph3YFW1CTAxpHNm3nBiKF3E0HlgNMyCxq0uGm+peylHsbrO V0FYkV2gdUMZ78HUvCOPzFyiH3zBjXTPIhuNEa6RB+Z6A== El 20/08/2025 a las 11:55, Borislav Petkov escribió: > On Wed, Aug 20, 2025 at 11:51:27AM +0200, Marcos Del Sol Vives wrote: >> I mean, they should know what they need to recompile if they want to, not >> just that their machine is having a bug triggered by some binary. > > And what's stopping you from writing a proper error message explaining that? > > And issuing that error message *exactly once* instead of flooding dmesg for no > good reason? Please define "once". Once per what? Per boot? Per executable? Per process? Once per boot would mean they'd need to reboot to see if any other executables are affected. Per executable AFAIK there are no facilities to do that, and the closest is per process which is what it's currently being done (again, like IOPL emulation which was already deemed okay a couple years ago and merged into the kernel)