Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755334AbaGOPiK (ORCPT ); Tue, 15 Jul 2014 11:38:10 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:51910 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103AbaGOPiI (ORCPT ); Tue, 15 Jul 2014 11:38:08 -0400 Date: Tue, 15 Jul 2014 11:38:01 -0400 From: Konrad Rzeszutek Wilk To: Andy Lutomirski Cc: "H. Peter Anvin" , boris.ostrovsky@oracle.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] x86_64,xen,espfix: Initialize espfix on secondary CPUs Message-ID: <20140715153801.GX3403@laptop.dumpdata.com> References: <195642a5e9fd4515ad8ca4cd8bcffd4900df5790.1405437568.git.luto@amacapital.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <195642a5e9fd4515ad8ca4cd8bcffd4900df5790.1405437568.git.luto@amacapital.net> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Thanks for posting this patch! > > arch/x86/xen/smp.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > index 7005974..eea9bcc 100644 > --- a/arch/x86/xen/smp.c > +++ b/arch/x86/xen/smp.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -85,6 +86,13 @@ static void cpu_bringup(void) > > xen_setup_cpu_clockevents(); > > + /* > + * Enable the espfix hack for this CPU > + */ > +#ifdef CONFIG_X86_ESPFIX64 > + init_espfix_ap(); > +#endif > + > notify_cpu_starting(cpu); > > set_cpu_online(cpu, true); > -- > 1.9.3 > -- 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/