From: Thomas Gleixner <tglx@linutronix.de>
To: "Van De Ven, Arjan" <arjan.van.de.ven@intel.com>
Cc: "Hansen, Dave" <dave.hansen@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
"x86@kernel.org" <x86@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>,
David Woodhouse <dwmw@amazon.co.uk>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Greg KH <gregkh@linuxfoundation.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
"Raj, Ashok" <ashok.raj@intel.com>
Subject: RE: [patch RFC 1/5] x86/CPU: Sync CPU feature flags late
Date: Wed, 10 Jan 2018 02:47:01 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1801100245010.2200@nanos> (raw)
In-Reply-To: <0575AF4FD06DD142AD198903C74E1CC87A571BD8@ORSMSX103.amr.corp.intel.com>
On Wed, 10 Jan 2018, Van De Ven, Arjan wrote:
> > In other words, if you use late microcode loading for getting IBRS, you
> > don't get ALTERNATIVE patching and its benefits?
> >
> > I'll also profess some microcode ignorance here. Is "late microcode
> > patching" *all* of the stuff we do from the OS, or do we have early and
> > late Linux loading in addition to what the BIOS can do?
>
> the early boot loader level stuff is much better generally (but does not
> work when the microcode comes out after the system booted... like really
> long uptimes)
That stuff indeed would be way simpler w/o the late support, but the fact
that the microcode for this might reach the user way later than the kernel
support makes it almost a must to support the late loading.
Thanks,
tglx
next prev parent reply other threads:[~2018-01-10 1:47 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-10 1:06 [patch RFC 0/5] x86/spectre_v2: Initial integration of IBRS into the spectre_v2 mechanics Thomas Gleixner
2018-01-10 1:06 ` [patch RFC 1/5] x86/CPU: Sync CPU feature flags late Thomas Gleixner
2018-01-10 1:37 ` Dave Hansen
2018-01-10 1:39 ` Van De Ven, Arjan
2018-01-10 1:47 ` Thomas Gleixner [this message]
2018-01-10 2:57 ` Andy Lutomirski
2018-01-10 11:02 ` Thomas Gleixner
2018-01-10 1:44 ` Thomas Gleixner
2018-01-10 6:20 ` Ingo Molnar
2018-01-10 11:33 ` Borislav Petkov
2018-01-10 12:38 ` Thomas Gleixner
2018-01-10 1:06 ` [patch RFC 2/5] x86/spectre: Simplify spectre code a bit Thomas Gleixner
2018-01-10 6:22 ` Ingo Molnar
2018-01-10 1:06 ` [patch RFC 3/5] x86/spectre: Prepare for IBRS selection Thomas Gleixner
2018-01-10 1:51 ` Dave Hansen
2018-01-10 1:06 ` [patch RFC 4/5] x86/cpufeatures: Detect Speculation control feature Thomas Gleixner
2018-01-10 6:32 ` Ingo Molnar
2018-01-10 11:06 ` Thomas Gleixner
2018-01-10 1:06 ` [patch RFC 5/5] x86/speculation: Add basic speculation control code Thomas Gleixner
2018-01-10 2:02 ` Dave Hansen
2018-01-10 4:11 ` Justin Forbes
2018-01-10 9:22 ` Peter Zijlstra
2018-01-10 9:27 ` David Woodhouse
2018-01-10 10:03 ` Peter Zijlstra
2018-01-10 11:22 ` David Woodhouse
2018-01-10 11:41 ` Thomas Gleixner
2018-01-10 11:45 ` Peter Zijlstra
2018-01-10 11:54 ` Andrea Arcangeli
2018-01-10 11:58 ` David Woodhouse
2018-01-10 12:01 ` Andrea Arcangeli
2018-01-10 12:07 ` Andrea Arcangeli
2018-01-10 12:12 ` David Woodhouse
2018-01-10 12:20 ` Andrea Arcangeli
2018-01-10 12:27 ` Andrea Arcangeli
2018-01-10 13:42 ` Van De Ven, Arjan
2018-01-10 12:09 ` David Woodhouse
2018-01-10 12:17 ` Andrea Arcangeli
2018-01-10 12:29 ` David Woodhouse
2018-01-10 12:41 ` Andrea Arcangeli
2018-01-10 12:47 ` Jiri Kosina
2018-01-10 12:51 ` David Woodhouse
2018-01-10 13:02 ` Andrea Arcangeli
2018-01-10 13:05 ` Andrea Arcangeli
2018-01-10 13:10 ` Andrea Arcangeli
2018-01-10 13:12 ` Andrea Arcangeli
2018-01-10 12:57 ` Andrea Arcangeli
2018-01-10 13:07 ` David Woodhouse
2018-01-10 13:45 ` Van De Ven, Arjan
2018-01-10 13:52 ` Andrea Arcangeli
2018-01-10 13:53 ` Van De Ven, Arjan
2018-01-10 21:35 ` Tim Chen
2018-01-10 22:13 ` Andrea Arcangeli
2018-01-10 13:46 ` Thomas Gleixner
2018-01-10 13:51 ` Van De Ven, Arjan
2018-01-10 13:53 ` Thomas Gleixner
2018-01-10 13:58 ` David Woodhouse
2018-01-10 14:10 ` Andrea Arcangeli
2018-01-10 14:14 ` Van De Ven, Arjan
2018-01-10 14:59 ` Dave Hansen
2018-01-10 15:13 ` Andrea Arcangeli
2018-01-10 15:24 ` David Woodhouse
2018-01-10 15:47 ` Andrea Arcangeli
2018-01-10 15:56 ` David Woodhouse
2018-01-10 13:10 ` Jiri Kosina
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