[09/12] x86/xen: save and restore steal clock
diff mbox series

Message ID 6f39a1594a25ab5325f34e1e297900d699cd92bf.1589926004.git.anchalag@amazon.com
State Superseded, archived
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Series
  • Fix PM hibernation in Xen guests
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Commit Message

Agarwal, Anchal May 19, 2020, 11:28 p.m. UTC
From: Munehisa Kamata <kamatam@amazon.com>

Save steal clock values of all present CPUs in the system core ops
suspend callbacks. Also, restore a boot CPU's steal clock in the system
core resume callback. For non-boot CPUs, restore after they're brought
up, because runstate info for non-boot CPUs are not active until then.

Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
Signed-off-by: Anchal Agarwal <anchalag@amazon.com>
---
 arch/x86/xen/suspend.c | 13 ++++++++++++-
 arch/x86/xen/time.c    |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

Comments

Boris Ostrovsky May 30, 2020, 11:44 p.m. UTC | #1
On 5/19/20 7:28 PM, Anchal Agarwal wrote:
> From: Munehisa Kamata <kamatam@amazon.com>
>
> Save steal clock values of all present CPUs in the system core ops
> suspend callbacks. Also, restore a boot CPU's steal clock in the system
> core resume callback. For non-boot CPUs, restore after they're brought
> up, because runstate info for non-boot CPUs are not active until then.
>
> Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
> Signed-off-by: Anchal Agarwal <anchalag@amazon.com>
> ---
>  arch/x86/xen/suspend.c | 13 ++++++++++++-
>  arch/x86/xen/time.c    |  3 +++
>  2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
> index 784c4484100b..dae0f74f5390 100644
> --- a/arch/x86/xen/suspend.c
> +++ b/arch/x86/xen/suspend.c
> @@ -91,12 +91,20 @@ void xen_arch_suspend(void)
>  static int xen_syscore_suspend(void)
>  {
>  	struct xen_remove_from_physmap xrfp;
> -	int ret;
> +	int cpu, ret;
>  
>  	/* Xen suspend does similar stuffs in its own logic */
>  	if (xen_suspend_mode_is_xen_suspend())
>  		return 0;
>  
> +	for_each_present_cpu(cpu) {
> +		/*
> +		 * Nonboot CPUs are already offline, but the last copy of
> +		 * runstate info is still accessible.
> +		 */
> +		xen_save_steal_clock(cpu);
> +	}
> +
>  	xrfp.domid = DOMID_SELF;
>  	xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT;
>  
> @@ -118,6 +126,9 @@ static void xen_syscore_resume(void)
>  
>  	pvclock_resume();


Doesn't make any difference but I think since this patch is where you
are dealing with clock then pvclock_resume() should be added here and
not in the earlier patch.


-boris


>  
> +	/* Nonboot CPUs will be resumed when they're brought up */
> +	xen_restore_steal_clock(smp_processor_id());
> +
>  	gnttab_resume();
>  }
>  
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index c8897aad13cd..33d754564b09 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -545,6 +545,9 @@ static void xen_hvm_setup_cpu_clockevents(void)
>  {
>  	int cpu = smp_processor_id();
>  	xen_setup_runstate_info(cpu);
> +	if (cpu)
> +		xen_restore_steal_clock(cpu);
> +
>  	/*
>  	 * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
>  	 * doing it xen_hvm_cpu_notify (which gets called by smp_init during
Agarwal, Anchal June 4, 2020, 6:33 p.m. UTC | #2
On Sat, May 30, 2020 at 07:44:06PM -0400, Boris Ostrovsky wrote:
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
> 
> 
> 
> On 5/19/20 7:28 PM, Anchal Agarwal wrote:
> > From: Munehisa Kamata <kamatam@amazon.com>
> >
> > Save steal clock values of all present CPUs in the system core ops
> > suspend callbacks. Also, restore a boot CPU's steal clock in the system
> > core resume callback. For non-boot CPUs, restore after they're brought
> > up, because runstate info for non-boot CPUs are not active until then.
> >
> > Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
> > Signed-off-by: Anchal Agarwal <anchalag@amazon.com>
> > ---
> >  arch/x86/xen/suspend.c | 13 ++++++++++++-
> >  arch/x86/xen/time.c    |  3 +++
> >  2 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
> > index 784c4484100b..dae0f74f5390 100644
> > --- a/arch/x86/xen/suspend.c
> > +++ b/arch/x86/xen/suspend.c
> > @@ -91,12 +91,20 @@ void xen_arch_suspend(void)
> >  static int xen_syscore_suspend(void)
> >  {
> >       struct xen_remove_from_physmap xrfp;
> > -     int ret;
> > +     int cpu, ret;
> >
> >       /* Xen suspend does similar stuffs in its own logic */
> >       if (xen_suspend_mode_is_xen_suspend())
> >               return 0;
> >
> > +     for_each_present_cpu(cpu) {
> > +             /*
> > +              * Nonboot CPUs are already offline, but the last copy of
> > +              * runstate info is still accessible.
> > +              */
> > +             xen_save_steal_clock(cpu);
> > +     }
> > +
> >       xrfp.domid = DOMID_SELF;
> >       xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT;
> >
> > @@ -118,6 +126,9 @@ static void xen_syscore_resume(void)
> >
> >       pvclock_resume();
> 
> 
> Doesn't make any difference but I think since this patch is where you
> are dealing with clock then pvclock_resume() should be added here and
> not in the earlier patch.
> 
> 
> -boris
I think the reason it may be in previous patch because it was a part
of syscore_resume and steal clock fix came in later. 
It could me moved to this patch that deals with all clock stuff.

-Anchal
> 
> 

> >
> > +     /* Nonboot CPUs will be resumed when they're brought up */
> > +     xen_restore_steal_clock(smp_processor_id());
> > +
> >       gnttab_resume();
> >  }
> >
> > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> > index c8897aad13cd..33d754564b09 100644
> > --- a/arch/x86/xen/time.c
> > +++ b/arch/x86/xen/time.c
> > @@ -545,6 +545,9 @@ static void xen_hvm_setup_cpu_clockevents(void)
> >  {
> >       int cpu = smp_processor_id();
> >       xen_setup_runstate_info(cpu);
> > +     if (cpu)
> > +             xen_restore_steal_clock(cpu);
> > +
> >       /*
> >        * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
> >        * doing it xen_hvm_cpu_notify (which gets called by smp_init during
> 
> 
>

Patch
diff mbox series

diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 784c4484100b..dae0f74f5390 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -91,12 +91,20 @@  void xen_arch_suspend(void)
 static int xen_syscore_suspend(void)
 {
 	struct xen_remove_from_physmap xrfp;
-	int ret;
+	int cpu, ret;
 
 	/* Xen suspend does similar stuffs in its own logic */
 	if (xen_suspend_mode_is_xen_suspend())
 		return 0;
 
+	for_each_present_cpu(cpu) {
+		/*
+		 * Nonboot CPUs are already offline, but the last copy of
+		 * runstate info is still accessible.
+		 */
+		xen_save_steal_clock(cpu);
+	}
+
 	xrfp.domid = DOMID_SELF;
 	xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT;
 
@@ -118,6 +126,9 @@  static void xen_syscore_resume(void)
 
 	pvclock_resume();
 
+	/* Nonboot CPUs will be resumed when they're brought up */
+	xen_restore_steal_clock(smp_processor_id());
+
 	gnttab_resume();
 }
 
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index c8897aad13cd..33d754564b09 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -545,6 +545,9 @@  static void xen_hvm_setup_cpu_clockevents(void)
 {
 	int cpu = smp_processor_id();
 	xen_setup_runstate_info(cpu);
+	if (cpu)
+		xen_restore_steal_clock(cpu);
+
 	/*
 	 * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
 	 * doing it xen_hvm_cpu_notify (which gets called by smp_init during