[Xen-devel] [PATCH v10 5/5] xen/arm: account for stolen ticks

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Register the runstate_memory_area with the hypervisor.
Use pv_time_ops.steal_clock to account for stolen ticks.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

---

Changes in v4:
- don't use paravirt_steal_rq_enabled: we do not support retrieving
stolen ticks for vcpus other than one we are running on.

Changes in v3:
- use BUG_ON and smp_processor_id.
---
 arch/arm/xen/enlighten.c |   21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index eeeab07..7dd2cc0 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -14,7 +14,10 @@
 #include <xen/xen-ops.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
+#include <asm/arch_timer.h>
 #include <asm/system_misc.h>
+#include <asm/paravirt.h>
+#include <linux/jump_label.h>
 #include <linux/interrupt.h>
 #include <linux/irqreturn.h>
 #include <linux/module.h>
@@ -79,6 +82,19 @@ int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
 
+static unsigned long long xen_stolen_accounting(int cpu)
+{
+       struct vcpu_runstate_info state;
+
+       BUG_ON(cpu != smp_processor_id());
+
+       xen_get_runstate_snapshot(&state);
+
+       WARN_ON(state.state != RUNSTATE_running);
+
+       return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
+}
+
 static void xen_percpu_init(void)
 {
        struct vcpu_register_vcpu_info info;
@@ -96,6 +112,8 @@ static void xen_percpu_init(void)
        BUG_ON(err);
        per_cpu(xen_vcpu, cpu) = vcpup;
 
+       xen_setup_runstate_info(cpu);
+
        enable_percpu_irq(xen_events_irq, 0);
        put_cpu();
 }
@@ -259,6 +277,9 @@ static int __init xen_guest_init(void)
 
        register_cpu_notifier(&xen_cpu_notifier);
 
+       pv_time_ops.steal_clock = xen_stolen_accounting;
+       static_key_slow_inc(&paravirt_steal_enabled);
+
        return 0;
 }
 early_initcall(xen_guest_init);
-- 
1.7.10.4


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