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 ; 10 Oct 2019 00:01:49 -0000 Received: from esa4.hc3370-68.iphmx.com ([216.71.155.144]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iILts-0005KC-5n for speck@linutronix.de; Thu, 10 Oct 2019 02:01:48 +0200 Subject: [MODERATED] Re: [PATCH v6 1/9] TAAv6 1 References: <761bccc8-4880-a190-a32f-98a487f0329e@citrix.com> <39d7dc3c-242b-693f-c950-05ccea9dc3df@citrix.com> <20191009235314.GA4287@agluck-desk2.amr.corp.intel.com> From: Andrew Cooper Message-ID: Date: Thu, 10 Oct 2019 01:01:38 +0100 MIME-Version: 1.0 In-Reply-To: <20191009235314.GA4287@agluck-desk2.amr.corp.intel.com> Content-Type: multipart/mixed; boundary="SPkXLg4HxCL7WM8LoGyagaSRMwNuTr9jc"; protected-headers="v1" To: speck@linutronix.de List-ID: --SPkXLg4HxCL7WM8LoGyagaSRMwNuTr9jc Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-GB On 10/10/2019 00:53, speck for Luck, Tony wrote: > On Thu, Oct 10, 2019 at 12:40:45AM +0100, speck for Andrew Cooper wrote= : >>> I don't know what the enabled status of HLE is on the MDS_NO, TAA par= ts, >>> and whether it is statically disabled with the TSX_CTRL microcode, bu= t >>> if it isn't statically disabled then it needs to be dynamically disab= led >>> by bit 0, or a 'CLFLUSH; XBEGIN ...; MOV secret' can still be used to= >>> exploit TAA. >> Apologies.=C2=A0 That is the RTM sequence. >> >> For HLE, I meant 'CLFLUSH; XAQUIRE ...; MOV secret'. > Did we send out a review copy of the white paper for TAA yet? Not as far as I am aware.=C2=A0 Have I missed something? I'm still working from the ppdf from June 26th, which I seem to recall was from just after the adjustment of bit 0's behaviour away from causing #UD's. > HLE is kind of buried, but we do say: > > On processors that enumerate IA32_ARCH_CAPABILITIES[TSX_CTRL] > (bit 7)=3D1, HLE prefix hints are always ignored. > > Which is to say that HLE is unconditionally disabled by the > new microcode for TAA. Great.=C2=A0 I look forward to a paper to review. Is that a firm decision on Ronak's suggestion that HLE is going to be sunset? ~Andrew --SPkXLg4HxCL7WM8LoGyagaSRMwNuTr9jc--