Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754183AbaGOQDD (ORCPT ); Tue, 15 Jul 2014 12:03:03 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:41423 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751540AbaGOQDA (ORCPT ); Tue, 15 Jul 2014 12:03:00 -0400 Message-ID: <53C5513F.7050707@oracle.com> Date: Tue, 15 Jul 2014 12:05:19 -0400 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Andy Lutomirski CC: Konrad Rzeszutek Wilk , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , stable Subject: Re: [PATCH] x86_64,xen,espfix: Initialize espfix on secondary CPUs References: <195642a5e9fd4515ad8ca4cd8bcffd4900df5790.1405437568.git.luto@amacapital.net> <20140715153801.GX3403@laptop.dumpdata.com> <53C54CA0.1060904@oracle.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/15/2014 11:54 AM, Andy Lutomirski wrote: > On Tue, Jul 15, 2014 at 8:45 AM, Boris Ostrovsky > wrote: >> On 07/15/2014 11:38 AM, Konrad Rzeszutek Wilk wrote: >>> On Tue, Jul 15, 2014 at 08:26:41AM -0700, Andy Lutomirski wrote: >>>> Xen doesn't call start_secondary. >>> Duh! >>>> Cc: stable@vger.kernel.org >>>> Signed-off-by: Andy Lutomirski >>>> --- >>>> >>>> espfix still doesn't seem to work on Xen (it goes boom in some way that >>>> I don't understand right now), but initializing all CPUs instead of just >>>> one of them seems like a good start. >>>> >>>> ISTM the right fix is probably to shove the espfix logic into >>>> native_iret and to tweak the paravirt logic so that native_iret always >>>> gets invoked. I suspect that Xen will need its own implementation of >>>> espfix64 in the hypervisor and that, ultimately, someone may want to >>>> stop initializing espfix64 at all on Xen guests. >>> I think just disallowing would be preferrable. >> >> I've been looking at sigreturn_64 and it seems to be crashing dom0 (with >> both mine and your patches). In kprobe_int3_handler(). > You need: > > http://lkml.kernel.org/g/c4e339882c121aa76254f2adde3fcbdf502faec2.1405099506.git.luto@amacapital.net > > The newer version of sigreturn_32 that I pushed is a much better test > -- it tests the 64-bit cases (yay thunks!) and works on kernels > without my SS sigcontext fix. Yes, that does it. At least we don't have yet another failure mode with this, which was the biggest concern. Thanks. -boris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/