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From: "Van De Ven, Arjan" <arjan.van.de.ven@intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Tim Chen <tim.c.chen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	"Hansen, Dave" <dave.hansen@intel.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <ak@linux.intel.com>,
	David Woodhouse <dwmw@amazon.co.uk>,
	"Williams, Dan J" <dan.j.williams@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3 3/5] x86/enter: Use IBRS on syscall and interrupts
Date: Wed, 10 Jan 2018 18:47:08 +0000	[thread overview]
Message-ID: <0575AF4FD06DD142AD198903C74E1CC87A572A2C@ORSMSX103.amr.corp.intel.com> (raw)
In-Reply-To: <20180110182856.GQ6176@hirez.programming.kicks-ass.net>

> On SKL+ retpoline is mostly there, but has a few dinky holes in and it
> _might_ make sense to use IBRS.
> 
> But I feel it needs explaining what the exact holes are (pjt and dwmw2
> had a fair enumeration IIRC) such that people can judge the risk.

you are correct to need and want this.

the problem is one of patch sequencing a bit;

as retpoline is now it has more of these dinky holes, in the next few days
patches will flow that will fix a bunch of these.

I would like to suggest we do the documentation part after a few days once 
we know how much of these we can reasonable pre-plug.

but yes we must do this tradeoff documentation.


  parent reply	other threads:[~2018-01-10 18:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-10  2:26 [PATCH v3 0/5] IBRS patch series Tim Chen
2018-01-10  2:26 ` [PATCH v3 1/5] x86/feature: Detect the x86 IBRS feature to control Speculation Tim Chen
2018-01-10  2:26 ` [PATCH v3 2/5] x86/enter: Create macros to set/clear IBRS Tim Chen
2018-01-11 16:04   ` Thomas Gleixner
2018-01-11 21:05     ` Tim Chen
2018-01-11 21:24       ` Tim Chen
2018-01-10  2:26 ` [PATCH v3 3/5] x86/enter: Use IBRS on syscall and interrupts Tim Chen
2018-01-10 10:04   ` Peter Zijlstra
2018-01-10 11:27     ` Paolo Bonzini
2018-01-10 18:16     ` Tim Chen
2018-01-10 18:28       ` Peter Zijlstra
2018-01-10 18:44         ` Tim Chen
2018-01-10 18:47         ` Van De Ven, Arjan [this message]
2018-01-11 12:45   ` Woodhouse, David
2018-01-10  2:26 ` [PATCH v3 4/5] x86/ibrs: Create boot option for IBRS Tim Chen
2018-01-10  2:26 ` [PATCH v3 5/5] x86/idle: Disable IBRS entering idle and enable it on wakeup Tim Chen

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