From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (193.142.43.55:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 24 Oct 2019 20:44:09 -0000 Received: from esa5.hc3370-68.iphmx.com ([216.71.155.168]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iNjxo-0000xh-8o for speck@linutronix.de; Thu, 24 Oct 2019 22:44:09 +0200 Subject: [MODERATED] Re: [PATCH 3/9] TAA 3 References: <580e02757c3e639bff00fcea830aa46eba46a92f.1571905227.git.bp@suse.de> <6f1ab744-622c-179b-276b-5506b2fd9ae1@citrix.com> <20191024194503.GH14115@zn.tnic> <20191024195959.nvdja4kxlbjrgq24@treble> <20191024200558.GJ14115@zn.tnic> <20191024201403.tibjxoywbd2rrjzq@treble> <20191024203600.GM14115@zn.tnic> From: Andrew Cooper Message-ID: Date: Thu, 24 Oct 2019 21:43:56 +0100 MIME-Version: 1.0 In-Reply-To: <20191024203600.GM14115@zn.tnic> Content-Type: multipart/mixed; boundary="GkkqxFpe0H6fFaSJ2Ov2FOkq4clE95tSK"; protected-headers="v1" To: speck@linutronix.de List-ID: --GkkqxFpe0H6fFaSJ2Ov2FOkq4clE95tSK Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-GB On 24/10/2019 21:36, speck for Borislav Petkov wrote: > On Thu, Oct 24, 2019 at 03:14:03PM -0500, speck for Josh Poimboeuf wrot= e: >> Actually, according to the patches, with TSX_CTRL CPUs, HLE is >> unconditionally disabled, but still enumerated as present in CPUID >> (why???) > I found it: in an older email thread Andrew talks about migration > compatibility and HLE. Dunno if we care but maybe someone else has a > better idea. The first TSX problem in Haswell/Broadwell lead to chaos when a microcode update took feature bits out. When the second problem came around, I understand from IRL conversations that several vendors firmly expressed their opinion about whether feature bits should disappear in microcode. As HLE is a hint bit at best, it was left visible despite being disabled behind the scenes. ~Andrew --GkkqxFpe0H6fFaSJ2Ov2FOkq4clE95tSK--