On Sat, May 30, 2020 at 07:44:06PM -0400, Boris Ostrovsky wrote:

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On 5/19/20 7:28 PM, Anchal Agarwal wrote:

quoted

From: Munehisa Kamata <redacted>

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 <redacted>
Signed-off-by: Anchal Agarwal <redacted>
---
 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

quoted

+     /* 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