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 47B33194137 for ; Thu, 16 Oct 2025 03:12:29 +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=1760584352; cv=none; b=kE0t1D6bLlBlWMfacCblXfNJ645SwXTiX8pZTBhwFdywGliDHnas/EV7EOSRbXmH8IV+EB17UUpzqF/w+BFXIur0na0x7yffm28iQP2ytxGgtUpKibMkTsXEFXoz6Z2djUBYdZhO0zOwNMki5eGI3GI0jq1Ex2uY0CC7NNVwK5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760584352; c=relaxed/simple; bh=Gpr6pMpqmS7OWb9GJ+hOB+VkU40x5ZrX809MGULl4nY=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=U4HUSxl1wAGIANRoshhEo4qtl4CN/qUncJ9kkmXZXA7Vn71XEdGIFGjRFl465lTVgYtnZZ6qcKaDAWHESkebLR0RiLHl6EHvAy8todwhJcSHMp6UmONBd5Sj+WiRVI2STLyMiVDrpUjblh/5dqqYgGOcmiNVzeMjDGqIohQ+SAk= 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=cRwPDWwK; 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="cRwPDWwK" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 59G3C9ZO2798968 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Wed, 15 Oct 2025 20:12:10 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 59G3C9ZO2798968 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025092201; t=1760584330; bh=Gpr6pMpqmS7OWb9GJ+hOB+VkU40x5ZrX809MGULl4nY=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=cRwPDWwK8J6lV0hGDPsJDidHXH9Y0YXu9Srb58bOctxF2mOLXqBQ0S5p3dpWmTeYK LPvfmgFH2kCfxvihPM4shYZ9IF7Q3Tq3M96bEBAoOnGC4VXJ/z3NKtsK+F2HjpjD5X UNrOrAwP/01PkPi+f58HzAYc1ewdNwWG5vyk7OoVMMsEBMk6HBU2F95vg2H7KaQsqB T0Z2HjNk3sUAW9JJiX9I2mxQATqGRXm4FS0/6CkPaLxKxqAk0GuiJRZ6g8aX+Q/hcl xDV7wndAEi31jr0hMnwwhbVyCSoHeYtGTI0T5S1pi/QcLRbzk5gUkIMT5KESS5Dn3f wvsKlsL+EqPOA== Date: Wed, 15 Oct 2025 20:12:08 -0700 From: "H. Peter Anvin" To: Borislav Petkov CC: Xin Li , Borislav Petkov , Xin Li , X86 ML , LKML Subject: Re: [PATCH] x86/cpufeatures: Correct LKGS feature flag description User-Agent: K-9 Mail for Android In-Reply-To: <20251015154911.GCaO_Cd0XNyE8bi5Db@fat_crate.local> References: <20251015103548.10194-1-bp@kernel.org> <2dd4dbee-dc7d-4118-be6d-94bd6d0d5030@zytor.com> <329BCA65-5152-4892-AFEA-DF72DCCE80B6@zytor.com> <530c3c1a-5fab-4798-830b-1fe0e8522bc9@zytor.com> <9B0843ED-5207-4A42-A95B-1DB5314DE747@zytor.com> <20251015154911.GCaO_Cd0XNyE8bi5Db@fat_crate.local> Message-ID: <4CDD31CE-7040-4ADB-B3F1-E095E3C5BDF5@zytor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On October 15, 2025 8:49:11 AM PDT, Borislav Petkov wrote: >On Wed, Oct 15, 2025 at 08:44:55AM -0700, H=2E Peter Anvin wrote: >> >> Except that that is also wrong, because that's not all of what the i= nstruction does=2E "Load user space GS" is really what it does, despite the= initiate historical naming=2E >> >>=20 >> > >> >Do you mean the load of GS attributes by LKGS is still missing? >>=20 >> Yes=2E It's really a modified MOV GS,=2E=2E=2E instruction that loads t= he base, limit, selector, and attributes; it just loads the base into a dif= ferent place=2E > >Ok, "Load user space GS base" it is=2E Considering how you can't load any= other >GS=2Ebase due to it GPing for CPL > 0=2E > No, "load user space GS=2E" It loads everything, not just the base=2E