From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:44662 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751874AbeCFSvL (ORCPT ); Tue, 6 Mar 2018 13:51:11 -0500 Subject: Patch "x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend" has been added to the 4.4-stable tree To: jgross@suse.com, gregkh@linuxfoundation.org, jbeulich@suse.com, tglx@linutronix.de Cc: , From: Date: Tue, 06 Mar 2018 10:50:09 -0800 Message-ID: <1520362209251104@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-xen-zero-msr_ia32_spec_ctrl-before-suspend.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 71c208dd54ab971036d83ff6d9837bae4976e623 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Mon, 26 Feb 2018 15:08:18 +0100 Subject: x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend From: Juergen Gross commit 71c208dd54ab971036d83ff6d9837bae4976e623 upstream. Older Xen versions (4.5 and before) might have problems migrating pv guests with MSR_IA32_SPEC_CTRL having a non-zero value. So before suspending zero that MSR and restore it after being resumed. Signed-off-by: Juergen Gross Signed-off-by: Thomas Gleixner Reviewed-by: Jan Beulich Cc: stable@vger.kernel.org Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Link: https://lkml.kernel.org/r/20180226140818.4849-1-jgross@suse.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/suspend.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -1,11 +1,14 @@ #include #include +#include #include #include #include #include +#include +#include #include #include #include @@ -68,6 +71,8 @@ static void xen_pv_post_suspend(int susp xen_mm_unpin_all(); } +static DEFINE_PER_CPU(u64, spec_ctrl); + void xen_arch_pre_suspend(void) { if (xen_pv_domain()) @@ -84,6 +89,9 @@ void xen_arch_post_suspend(int cancelled static void xen_vcpu_notify_restore(void *data) { + if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL)) + wrmsrl(MSR_IA32_SPEC_CTRL, this_cpu_read(spec_ctrl)); + /* Boot processor notified via generic timekeeping_resume() */ if (smp_processor_id() == 0) return; @@ -93,7 +101,15 @@ static void xen_vcpu_notify_restore(void static void xen_vcpu_notify_suspend(void *data) { + u64 tmp; + tick_suspend_local(); + + if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL)) { + rdmsrl(MSR_IA32_SPEC_CTRL, tmp); + this_cpu_write(spec_ctrl, tmp); + wrmsrl(MSR_IA32_SPEC_CTRL, 0); + } } void xen_arch_resume(void) Patches currently in stable-queue which might be from jgross@suse.com are queue-4.4/x86-xen-zero-msr_ia32_spec_ctrl-before-suspend.patch