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 BC47434545; Tue, 3 Jun 2025 16:35:18 +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=1748968521; cv=none; b=FgbImmidFWocfdkQ4tiFDh/dk2LxRbrdn9SMKdjqVBxNU94EtahaZr6cMr73qgnAOAz82/beBF1otiMBk45FtwvkQvMzfA326dLhv8XwGbS8eSQ4Mr9uL4wJz04rZNRaV16LEwh6Xd9cNxq1wVADbaFGipNkA9hNGOPJ8qbUu7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748968521; c=relaxed/simple; bh=nxaCfdWauzjNiTIgCxophxKa0Ige88EfFoo8WmagOwk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=mIOJu5WerhNuLDzT1V8v+hVJ1OTvAql8sCOFyuJjhPkRB1b2t4wVX/jJ5cTfEokjBow2rIkRIG10MjaF693a9LY+DgXvkbCjlIL4DBW8jFFjX3grzn+fKMrul+6j7RV8hcTxq3DJctJq655VJOJxzd8acMRzbf/Xc72j9jBTxGg= 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=YU5sBwUz; 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="YU5sBwUz" 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 553GYR2v3906763 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 3 Jun 2025 09:34:28 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 553GYR2v3906763 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025052101; t=1748968479; bh=B4whhvRWBFRCoJ6hVF+KD7HMcx0awQWFQvakW3OGf4s=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=YU5sBwUzJA0fHvoPTdDw7FhsWEYRZK4g72VOSHCcdCFCiV150jNxjEO3uz+G6o7an voHH+OdGZvMTqANn6sJHxVJ7RaSCdxfDEdXJSj06CHtfk7zu7T6LiAg12rawuZ1Ap5 DW7SJGAKuGccnPD980W1wh9jcmFdWaUKJW5FHnZD5u1CJtqZjiKH0yzo/Xxh5V58Pi V2p2Y4K+UYvNEDovZ9cZ4+mKmFYAps9lHtuwSx7aOZZjDyrDpAAiE3QrQTLI56hsCR Wvl7zYm1rM/j8OpZwidt/pnU6Mc/A5rGE6BMzFcjbl0Ru2EgRYUSO/jZ7zeWHA4XSW HAT7481f5BVWg== Message-ID: <9950dc5a-05ab-4a7c-a4e8-34012ef98549@zytor.com> Date: Tue, 3 Jun 2025 09:34:27 -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 v6 4/9] x86/nmi: Assign and register NMI-source vectors To: Sohil Mehta , x86@kernel.org, linux-kernel@vger.kernel.org Cc: "H . Peter Anvin" , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Peter Zijlstra , Sean Christopherson , Adrian Hunter , Kan Liang , Tony Luck , Zhang Rui , Steven Rostedt , Andrew Cooper , "Kirill A . Shutemov" , Jacob Pan , Andi Kleen , Kai Huang , Sandipan Das , linux-perf-users@vger.kernel.org, linux-edac@vger.kernel.org, kvm@vger.kernel.org, linux-pm@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20250513203803.2636561-1-sohil.mehta@intel.com> <20250513203803.2636561-5-sohil.mehta@intel.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: <20250513203803.2636561-5-sohil.mehta@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/13/2025 1:37 PM, Sohil Mehta wrote: > Prior to NMI-source support, the vector information was ignored by the > hardware while delivering NMIs. With NMI-source, the architecture > currently supports a 16-bit source bitmap to identify the source of the > NMI. Upon receiving an NMI, this bitmap is delivered as part of the FRED > event delivery mechanism to the kernel. > > Assign a vector space of 0-15 that is specific to NMI-source and > independent of the IDT vector space of 0-255. Being a bitmap, the > NMI-source vectors do not have any inherent priority associated with > them. The order of executing the NMI handlers is up to the kernel. I'm thinking should we mention that the bitmap could be extended more than 16 bits in future? Or we just don't emphasize 16-bit or 0~15? > > Existing NMI handling already has a priority mechanism for the NMI > handlers, with CPU-specific (NMI_LOCAL) handlers executed first, > followed by platform NMI handlers and unknown NMI (NMI_UNKNOWN) handlers > being last. Within each of these NMI types, the handlers registered with > NMI_FLAG_FIRST are given priority. > > NMI-source follows the same priority scheme to avoid unnecessary > complexity. Therefore, the NMI-source vectors are assigned arbitrarily, > except for vectors 0 and 2. > > Vector 0 is set by the hardware whenever a source vector was not used > while generating an NMI or the originator could not be reliably > identified. Do not assign it to any handler. > > Vector 2 is reserved for external NMIs corresponding to Local APIC - > LINT1. Some third-party chipsets may send NMI messages with a hardcoded > vector of 2, which would result in vector 2 being set in the NMI-source > bitmap. To avoid confusion, do not assign vector 2 to any handler. > > NMI-source vectors are only assigned for NMI_LOCAL type handlers. > Platform NMI handlers have a single handler registered per type. They > don't need additional source information to differentiate among them. > > Use the assigned vectors to register the respective NMI handlers. Warn > if the vector values are unexpected. > > A couple of NMI handlers, such as the microcode rendezvous and the crash > reboot, do not use the typical NMI registration interface. Leave them > as-is for now. > > Originally-by: Jacob Pan > Signed-off-by: Sohil Mehta Reviewed-by: Xin Li (Intel)