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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH v7 00/10] TAAv7 0
Date: Tue, 22 Oct 2019 00:06:18 +0100	[thread overview]
Message-ID: <e8ef154a-53d1-aef3-e109-a38f0970b285@citrix.com> (raw)
In-Reply-To: <ba64d6d5-370a-7be8-1465-9a132fd0ce3a@amacapital.net>

[-- Attachment #1: Type: text/plain, Size: 1318 bytes --]

On 21/10/2019 22:32, speck for Andy Lutomirski wrote:
> On 10/21/19 1:22 PM, speck for Pawan Gupta wrote:
>> From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
>> Subject: [PATCH v7 00/10] TAAv7
>>
>> Changes since v6:
>> - Add Michal's patch to allow tsx=on|off|auto via CONFIG
>> - Rebase to v5.4-rc4
>> - Changelog, comments and documentation update.
>>
>> Changes since v5:
>> - Remove unsafe X86_FEATURE_RTM toggles.
> I'm wondering if maybe these patches shouldn't touch the cpu
> capabilities at all.  After all, even with TSX toggled off, TSX is still
> present -- XBEGIN doesn't give #UD.

So, there is some history here.

The first microcode version had XBEGIN giving #UD, and a fair chunk of
ancillary behaviour revolved around that.

However, that is rather catastrophic for late-loading the microcode and
securing the system in place, so the behaviour was relaxed from #UD to
abort.

That way, folk who late-load the microcode can secure their systems by
setting the RTM_ABORT bit, and folk booting "fresh" with the new
microcode can set both the RTM_ABORT and CPUID bits, to cause userspace
to believe there is no RTM at all, and avoid their unconditional abort.

~Andrew

P.S. I did ask if we could have both #UD and abort, and got a firm no
based on patch space.


  reply	other threads:[~2019-10-21 23:06 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-21 20:22 [MODERATED] [PATCH v7 00/10] TAAv7 0 Pawan Gupta
2019-10-21 20:23 ` [MODERATED] [PATCH v7 01/10] TAAv7 1 Pawan Gupta
2019-10-21 20:24 ` [MODERATED] [PATCH v7 02/10] TAAv7 2 Pawan Gupta
2019-10-21 20:25 ` [MODERATED] [PATCH v7 03/10] TAAv7 3 Pawan Gupta
2019-10-21 20:26 ` [MODERATED] [PATCH v7 04/10] TAAv7 4 Pawan Gupta
2019-10-21 20:27 ` [MODERATED] [PATCH v7 05/10] TAAv7 5 Pawan Gupta
2019-10-21 20:28 ` [MODERATED] [PATCH v7 06/10] TAAv7 6 Pawan Gupta
2019-10-21 20:29 ` [MODERATED] [PATCH v7 07/10] TAAv7 7 Pawan Gupta
2019-10-21 20:30 ` [MODERATED] [PATCH v7 08/10] TAAv7 8 Pawan Gupta
2019-10-21 20:31 ` [MODERATED] [PATCH v7 09/10] TAAv7 9 Michal Hocko
2019-10-21 20:32 ` [MODERATED] [PATCH v7 10/10] TAAv7 10 Pawan Gupta
2019-10-21 21:32 ` [MODERATED] Re: [PATCH v7 00/10] TAAv7 0 Andy Lutomirski
2019-10-21 23:06   ` Andrew Cooper [this message]
2019-10-22  0:34   ` Pawan Gupta
2019-10-22  4:10 ` [MODERATED] Jon Masters
2019-10-22  5:53   ` [MODERATED] Pawan Gupta
2019-10-22  7:58 ` [MODERATED] Re: ***UNCHECKED*** [PATCH v7 07/10] TAAv7 7 Michal Hocko
2019-10-22 16:55   ` [MODERATED] " Pawan Gupta
2019-10-22  8:00 ` [MODERATED] Re: ***UNCHECKED*** [PATCH v7 09/10] TAAv7 9 Michal Hocko
2019-10-22  8:15 ` [MODERATED] Re: ***UNCHECKED*** [PATCH v7 03/10] TAAv7 3 Michal Hocko
2019-10-22 14:42   ` Josh Poimboeuf
2019-10-22 16:48     ` [MODERATED] " Pawan Gupta
2019-10-22 17:01       ` [MODERATED] Re: ***UNCHECKED*** " Michal Hocko
2019-10-22 17:35         ` Josh Poimboeuf
2019-10-22 14:38 ` [MODERATED] " Borislav Petkov
2019-10-22 16:58   ` Pawan Gupta
2019-10-22 14:48 ` Borislav Petkov
2019-10-22 17:00   ` Pawan Gupta
2019-10-22 17:16     ` [MODERATED] " Borislav Petkov
2019-10-22 18:07       ` [MODERATED] " Pawan Gupta
2019-10-22 15:07 ` Borislav Petkov
2019-10-22 18:36   ` Pawan Gupta
2019-10-22 18:59     ` [MODERATED] " Borislav Petkov
2019-10-22 16:51 ` [MODERATED] Re: [PATCH v7 04/10] TAAv7 4 Borislav Petkov
2019-10-22 17:02   ` Borislav Petkov
2019-10-22 18:00     ` Pawan Gupta
2019-10-22 18:12       ` [MODERATED] " Borislav Petkov
2019-10-22 19:16         ` Luck, Tony
2019-10-22 19:28           ` [MODERATED] " Borislav Petkov
2019-10-22 20:02             ` Luck, Tony
2019-10-22 20:48               ` [MODERATED] Jon Masters
2019-10-22 20:54               ` [MODERATED] Re: [PATCH v7 04/10] TAAv7 4 Borislav Petkov
2019-10-22 21:38                 ` Josh Poimboeuf
2019-10-22 21:46                   ` Borislav Petkov
2019-10-22 22:06                     ` Josh Poimboeuf
2019-10-22 22:13                       ` Borislav Petkov
2019-10-22 17:44   ` Pawan Gupta
2019-10-22 19:04     ` [MODERATED] " Borislav Petkov
2019-10-22 21:29       ` [MODERATED] " Pawan Gupta
2019-10-22 21:53         ` Borislav Petkov
2019-10-22 22:05           ` Borislav Petkov
2019-10-23  0:27             ` Pawan Gupta
2019-10-23  5:25               ` Pawan Gupta
2019-10-23  6:46                 ` Borislav Petkov
2019-10-23 13:28                   ` Pawan Gupta
2019-10-23 14:39                     ` Borislav Petkov
2019-10-23  1:33   ` Pawan Gupta
2019-10-23  6:48     ` Borislav Petkov
2019-10-22 17:25 ` [MODERATED] Re: [PATCH v7 01/10] TAAv7 1 Josh Poimboeuf
2019-10-23  9:26   ` Borislav Petkov
2019-10-22 17:26 ` Josh Poimboeuf
2019-10-22 20:44   ` [MODERATED] Jon Masters
2019-10-22 17:47 ` [MODERATED] Re: [PATCH v7 03/10] TAAv7 3 Josh Poimboeuf
2019-10-22 18:39 ` [MODERATED] Re: [PATCH v7 10/10] TAAv7 10 Josh Poimboeuf
2019-10-23  7:24   ` Borislav Petkov
2019-10-22 21:20 ` [MODERATED] Re: [PATCH v7 04/10] TAAv7 4 Josh Poimboeuf
2019-10-22 21:35   ` Andrew Cooper
2019-10-22 21:44     ` Josh Poimboeuf
2019-10-22 22:03       ` Andrew Cooper
2019-10-23  1:16         ` Josh Poimboeuf
2019-10-23 15:46 ` [MODERATED] Re: [PATCH v7 00/10] TAAv7 0 Borislav Petkov
2019-10-23 17:11   ` Josh Poimboeuf
2019-10-23 21:49     ` Borislav Petkov
2019-10-23 22:12   ` Pawan Gupta
2019-10-24 14:08     ` Borislav Petkov
     [not found] ` <5dae165e.1c69fb81.4beee.e271SMTPIN_ADDED_BROKEN@mx.google.com>
2019-10-24 20:53   ` [MODERATED] Re: [PATCH v7 06/10] TAAv7 6 Paolo Bonzini
2019-10-24 21:00     ` Luck, Tony
2019-10-24 21:33       ` Paolo Bonzini

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