From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 5FCD027A90A for ; Tue, 22 Jul 2025 17:22:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753204947; cv=none; b=cu828cUP3fvdsKJKWTAZMy4dEaZgkZWLVwtipbqO1R4N5dd6hoEuXGIk6uyEAu/ly2yvGJcmkhEOIojZ1Sd3LmiXoxMF/6TOVsK5Sm8Tp0nhYMl2xAEfTyEPlBeCSY55dHGz/7p20m9HuYvYVaEPRw3Nz/c0vmlVzhyoeAzCl30= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753204947; c=relaxed/simple; bh=5UEi2NC+5Xrit0iKinNdi3nmduJtK6vG27yCY7e8BhU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WRhNkUO+yTxh5vztMOeqDFma30vfm/YqqvPlh36k5WuIm8GBprBWJ36f5BKynuPXGKdqh961lu6mA/Og+Z2CxvmOiEBRJE8ooAK2AMNP8nR/5GQc38jDZ5IRHVZcShCpuZhAloqJtVu9kBKd1JHwJZLUar+nU6mHgQ6prilwwt8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=PpTMaOy1; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="PpTMaOy1" Received: from [192.168.7.202] ([71.202.166.45]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 56MHM1bn666510 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 22 Jul 2025 10:22:01 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 56MHM1bn666510 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025062101; t=1753204922; bh=aqASFZb/hAVrA9isA+NHDa8/g4iNldjIhQygK7/qfY0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PpTMaOy1E1ZVpdZ8vJy7oAlGJrV2keXIkifpxVd9rtb1OwaIWyiJi/Fo+OY3v+UCn JTno5ANvfEWhi1KVkct4I3T6b1odOX9yefV4Dh3mETwmPcI9fxuNXSzY92n+69zSxT QQDgKA0tyfKIFhHlnYatH5hcseBN/zpTWBAihoa0pK41/1hs7eim/OGLDrGuYCdCsX xE79OL25+4W2XPZwmHiDpsvetJdsDt4RgDEuapX7tWfRk7rxHw4BlhAlTAJD+FPrpX D36huasW4+yGP8o+gi5a9C+XLcHkfvBKrwJVZeRUM7Pj800yKbazyPDcTUwi8kH8m6 5EGg2LK7cr8Fw== Message-ID: <5654b3bc-15d4-443b-a7b1-2f9fd1d3e0aa@zytor.com> Date: Tue, 22 Jul 2025 10:22:01 -0700 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: Clear LAM and FRED feature bits To: "H. Peter Anvin" , Wieczor-Retman Maciej Cc: Gleixner Thomas , Molnar Ingo , Petkov Borislav , Hansen Dave , x86@kernel.org, linux-kernel@vger.kernel.org References: <20250722074439.4069992-1-maciej.wieczor-retman@intel.com> <32382f60-79fb-4cfa-87b4-581f92c980da@zytor.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; keydata= xsDNBGUPz1cBDACS/9yOJGojBFPxFt0OfTWuMl0uSgpwk37uRrFPTTLw4BaxhlFL0bjs6q+0 2OfG34R+a0ZCuj5c9vggUMoOLdDyA7yPVAJU0OX6lqpg6z/kyQg3t4jvajG6aCgwSDx5Kzg5 Rj3AXl8k2wb0jdqRB4RvaOPFiHNGgXCs5Pkux/qr0laeFIpzMKMootGa4kfURgPhRzUaM1vy bsMsL8vpJtGUmitrSqe5dVNBH00whLtPFM7IbzKURPUOkRRiusFAsw0a1ztCgoFczq6VfAVu raTye0L/VXwZd+aGi401V2tLsAHxxckRi9p3mc0jExPc60joK+aZPy6amwSCy5kAJ/AboYtY VmKIGKx1yx8POy6m+1lZ8C0q9b8eJ8kWPAR78PgT37FQWKYS1uAroG2wLdK7FiIEpPhCD+zH wlslo2ETbdKjrLIPNehQCOWrT32k8vFNEMLP5G/mmjfNj5sEf3IOKgMTMVl9AFjsINLHcxEQ 6T8nGbX/n3msP6A36FDfdSEAEQEAAc0WWGluIExpIDx4aW5Aenl0b3IuY29tPsLBDQQTAQgA NxYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89XBQkFo5qAAhsDBAsJCAcFFQgJCgsFFgID AQAACgkQa70OVx2uN1HUpgv/cM2fsFCQodLArMTX5nt9yqAWgA5t1srri6EgS8W3F+3Kitge tYTBKu6j5BXuXaX3vyfCm+zajDJN77JHuYnpcKKr13VcZi1Swv6Jx1u0II8DOmoDYLb1Q2ZW v83W55fOWJ2g72x/UjVJBQ0sVjAngazU3ckc0TeNQlkcpSVGa/qBIHLfZraWtdrNAQT4A1fa sWGuJrChBFhtKbYXbUCu9AoYmmbQnsx2EWoJy3h7OjtfFapJbPZql+no5AJ3Mk9eE5oWyLH+ QWqtOeJM7kKvn/dBudokFSNhDUw06e7EoVPSJyUIMbYtUO7g2+Atu44G/EPP0yV0J4lRO6EA wYRXff7+I1jIWEHpj5EFVYO6SmBg7zF2illHEW31JAPtdDLDHYcZDfS41caEKOQIPsdzQkaQ oW2hchcjcMPAfyhhRzUpVHLPxLCetP8vrVhTvnaZUo0xaVYb3+wjP+D5j/3+hwblu2agPsaE vgVbZ8Fx3TUxUPCAdr/p73DGg57oHjgezsDNBGUPz1gBDAD4Mg7hMFRQqlzotcNSxatlAQNL MadLfUTFz8wUUa21LPLrHBkUwm8RujehJrzcVbPYwPXIO0uyL/F///CogMNx7Iwo6by43KOy g89wVFhyy237EY76j1lVfLzcMYmjBoTH95fJC/lVb5Whxil6KjSN/R/y3jfG1dPXfwAuZ/4N cMoOslWkfZKJeEut5aZTRepKKF54T5r49H9F7OFLyxrC/uI9UDttWqMxcWyCkHh0v1Di8176 jjYRNTrGEfYfGxSp+3jYL3PoNceIMkqM9haXjjGl0W1B4BidK1LVYBNov0rTEzyr0a1riUrp Qk+6z/LHxCM9lFFXnqH7KWeToTOPQebD2B/Ah5CZlft41i8L6LOF/LCuDBuYlu/fI2nuCc8d m4wwtkou1Y/kIwbEsE/6RQwRXUZhzO6llfoN96Fczr/RwvPIK5SVMixqWq4QGFAyK0m/1ap4 bhIRrdCLVQcgU4glo17vqfEaRcTW5SgX+pGs4KIPPBE5J/ABD6pBnUUAEQEAAcLA/AQYAQgA JhYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89ZBQkFo5qAAhsMAAoJEGu9DlcdrjdR4C0L /RcjolEjoZW8VsyxWtXazQPnaRvzZ4vhmGOsCPr2BPtMlSwDzTlri8BBG1/3t/DNK4JLuwEj OAIE3fkkm+UG4Kjud6aNeraDI52DRVCSx6xff3bjmJsJJMb12mWglN6LjdF6K+PE+OTJUh2F dOhslN5C2kgl0dvUuevwMgQF3IljLmi/6APKYJHjkJpu1E6luZec/lRbetHuNFtbh3xgFIJx 2RpgVDP4xB3f8r0I+y6ua+p7fgOjDLyoFjubRGed0Be45JJQEn7A3CSb6Xu7NYobnxfkwAGZ Q81a2XtvNS7Aj6NWVoOQB5KbM4yosO5+Me1V1SkX2jlnn26JPEvbV3KRFcwV5RnDxm4OQTSk PYbAkjBbm+tuJ/Sm+5Yp5T/BnKz21FoCS8uvTiziHj2H7Cuekn6F8EYhegONm+RVg3vikOpn gao85i4HwQTK9/D1wgJIQkdwWXVMZ6q/OALaBp82vQ2U9sjTyFXgDjglgh00VRAHP7u1Rcu4 l75w1xInsg== In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/22/2025 9:46 AM, H. Peter Anvin wrote: >> The following code will work as a generic fix: >> >> c->x86_capability[i] &= ~DISABLED_MASK(i); >> >> And DISABLED_MASK(x) needs to be defined like DISABLED_MASK_BIT_SET(x). >> >> Thanks! >> Xin > The easiest thing would be to initialize the setup disabled mask with the DISABLED bitmask instead of zero. This can be done statically; if it isn't already the awk script can produce the disabled bitmask in array form. Yes, something like: void __init init_cpu_cap(void) { for (i = 0; i < NCAPINTS; i++) { cpu_caps_set[i] = REQUIRED_MASK(i); cpu_caps_cleared[i] = DISABLED_MASK(i); } } And it would be better if it could be done at build time (to avoid changing Xen which has a dedicated startup code path): __u32 cpu_caps_{set,cleared}[NCAPINTS + NBUGINTS] = { {REQUIRED,DISABLED}_MASK(i), }; And then apply_forced_caps() will do the rest automatically :)