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Commit 71c208dd authored by Juergen Gross's avatar Juergen Gross Committed by Thomas Gleixner
Browse files

x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend 



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: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
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
parent 946fbbc1

arch/x86/xen/suspend.c

+16 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/types.h>

#include <linux/tick.h>

#include <linux/percpu-defs.h>



#include <xen/xen.h>

#include <xen/interface/xen.h>

#include <xen/grant_table.h>

#include <xen/events.h>



#include <asm/cpufeatures.h>

#include <asm/msr-index.h>

#include <asm/xen/hypercall.h>

#include <asm/xen/page.h>

#include <asm/fixmap.h>
@@ -15,6 +18,8 @@ 
#include "mmu.h"

#include "pmu.h"



static DEFINE_PER_CPU(u64, spec_ctrl);



void xen_arch_pre_suspend(void)

{

	xen_save_time_memory_area();
@@ -35,6 +40,9 @@ 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;
@@ -44,7 +52,15 @@ static void xen_vcpu_notify_restore(void *data) 


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)