From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 263713A3E78 for ; Tue, 19 May 2026 19:29:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779218954; cv=none; b=HrMcYODQjRiuwtiszsjwuACCdNVZ5fSljh9kAoozL91KHAjoI3rwGPMiNwgu/NNG4duT1el91MombU6wans0MVfyWTKDosxC3VrKYnFg2gNjQLNrqvzsJlLKAQkh12EtDYWUiYtJfQ6LZ+Ulyg9GL48OcLF6+so2w6b8CRKNtd8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779218954; c=relaxed/simple; bh=2K6XCedv4QLe2vpXskFpc2c3i93VbwXmXNnYj4/6VA0=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=F66tkhMZVUzZcHOQ60ABzQc/9+SFAGHbM3OtdrTh+h28qsDF9o1oquKCoufjL9LUjoyhoShfqdzr7cUoP+Iz2BUyt029GukE4VnesZi71rqaiFwNifAf0jcdE/ujBZQPuNxiiF7E5IjfPdNwgOi6rhGA9BIo1TjhMUdtGbikQOM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b=P6gGU2ll; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b="P6gGU2ll" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=2K6XCedv4QLe2vpXskFpc2c3i93VbwXmXNnYj4/6VA0=; b=P6gGU2llJcEE0ToYValGYVBHpc aCRwjRPORut+W2PvSTSHL/JIAVR3mJuWVd7UT3E4QkyKxYrmyCBMZcda5BDMgEb4wmAl7zU5+AGaZ OJ613XxNlBfAIr0/EEPhUk0GpTQcuWTFwQC8Xsd8x3SZd5CEuIWrcvTrDrvALRxyHcx7MGD8nkSaw 9J2iXkRc1Yfi7b7Y5R741QO2ZyBaBgQrWa6jP80RoeUyvsNPq0lT9KkMXMv+bMI755ARaZTweKp5N lT0uyX/7lzAW3JSIvhhf4Hp9gMze3V+QMDbhIlW3Ri5CHKM6t8TaTGPPAx7iZ2QP20PD09hOQNJEI DNTKfkTA==; Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1wPQ7V-000000003GF-3Mjf; Tue, 19 May 2026 15:28:49 -0400 Message-ID: <590444fbdac331e9673e1222a186218d526d779b.camel@surriel.com> Subject: Re: [PATCH v2] x86/mm: Disable broadcast TLB flush when PCID is disabled From: Rik van Riel To: Tom Lendacky , linux-kernel@vger.kernel.org, x86@kernel.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Nadav Amit , Dave Hansen Date: Tue, 19 May 2026 15:28:49 -0400 In-Reply-To: References: Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-05-19 at 14:22 -0500, Tom Lendacky wrote: >=20 > All processors that support broadcast TLB invalidation also have PCID > support, so it is only the "nopcid" scenario that is of concern. In > this situation just disable the broadcast TLB support using the CPUID > dependency support by making X86_FEATURE_INVLPGB dependent on > X86_FEATURE_PCID. >=20 > Fixes: 4afeb0ed1753 ("x86/mm: Enable broadcast TLB invalidation for > multi-threaded processes") > Assisted-by: Claude:claude-opus-4.7 > Suggested-by: Dave Hansen > Signed-off-by: Tom Lendacky Acked-by: Rik van Riel --=20 All Rights Reversed.