From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <4F46C3CF.40303@zytor.com> Date: Thu, 23 Feb 2012 14:55:11 -0800 From: "H. Peter Anvin" MIME-Version: 1.0 To: Willy Tarreau CC: Linus Torvalds , Greg Kroah-Hartman , stable@vger.kernel.org, Raphael Prevost , Suresh Siddha , Linux Kernel Mailing List Subject: Re: [PATCH 0/5] i387: stable kernel backport References: <20120223200905.GA5475@kroah.com> <4F46A1C4.90506@zytor.com> <20120223204832.GA30322@kroah.com> <4F46A6EC.8050804@zytor.com> <20120223211016.GA16275@kroah.com> <20120223215242.GA1306@1wt.eu> <20120223222733.GB1306@1wt.eu> <4F46C253.106@zytor.com> <20120223225227.GD1306@1wt.eu> In-Reply-To: <20120223225227.GD1306@1wt.eu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: On 02/23/2012 02:52 PM, Willy Tarreau wrote: > On Thu, Feb 23, 2012 at 02:48:51PM -0800, H. Peter Anvin wrote: >> On 02/23/2012 02:38 PM, Linus Torvalds wrote: >>> >>> You'd still need an x86-32 machine to test on, because x86-64 was >>> immune to this issue. >>> >>> But yeah, the impact of this seems to be small enough that for older >>> kernels (which are likely used on older systems for maintenance >>> anyway) disabling AES-NI on x86-32 really might be the way to go. >>> >> >> That would really suck for users of encrypted hard disks. > > Peter, do you really think there are that many ? I think I only saw > AES-NI on recent 64-bit capable chips, and it's been a while that > users have been installing 64-bit distros on such machines. Note that > I'm not advocating for breaking existing setups, just that I'm surprized > by this combination (aes-ni + 32-bit). > There are still people running 32-bit systems because they have some odd compatibility constraints but now have to deal with corporate or other security constraints; they may also have been using disk encryption since before AES-NI was in but doing it on the integer side is way slower. This is not AES-NI in the interrupt path, but I don't think there is a knob for that. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.