[PATCH 3/2] context_tracking: move rcu_virt_note_context_switch out of kvm_host.h

Paolo Bonzini
2016-06-20T15:00:48Z

Make kvm_guest_{enter,exit} and __kvm_guest_{enter,exit} trivial wrappers
around the code in context_tracking.h. Name the context_tracking.h functions
consistently with what those for kernel<->user switch.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/linux/context_tracking.h | 38 ++++++++++++++++++++++++++++++++++----
include/linux/kvm_host.h | 25 ++++---------------------
2 files changed, 38 insertions(+), 25 deletions(-)

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index d9aef2a0ec8e..c78fc27418f2 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -99,7 +99,8 @@ static inline void context_tracking_init(void) { }

#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-static inline void guest_enter(void)
+/* must be called with irqs disabled */
+static inline void guest_enter_irqoff(void)
{
if (vtime_accounting_cpu_enabled())
vtime_guest_enter(current);
@@ -108,9 +109,19 @@ static inline void guest_enter(void)

if (context_tracking_is_enabled())
__context_tracking_enter(CONTEXT_GUEST);
+
+ /* KVM does not hold any references to rcu protected data when it
+ * switches CPU into a guest mode. In fact switching to a guest mode
+ * is very similar to exiting to userspace from rcu point of view. In
+ * addition CPU may stay in a guest mode for quite a long time (up to
+ * one time slice). Lets treat guest mode as quiescent state, just like
+ * we do with user-mode execution.
+ */
+ if (!context_tracking_cpu_is_enabled())
+ rcu_virt_note_context_switch(smp_processor_id());
}

-static inline void guest_exit(void)
+static inline void guest_exit_irqoff(void)
{
if (context_tracking_is_enabled())
__context_tracking_exit(CONTEXT_GUEST);
@@ -122,7 +133,7 @@ static inline void guest_exit(void)
}

#else
-static inline void guest_enter(void)
+static inline void guest_enter_irqoff(void)
{
/*
* This is running in ioctl context so its safe
@@ -131,9 +142,10 @@ static inline void guest_enter(void)
*/
vtime_account_system(current);
current->flags |= PF_VCPU;
+ rcu_virt_note_context_switch(smp_processor_id());
}

-static inline void guest_exit(void)
+static inline void guest_exit_irqoff(void)
{
/* Flush the guest cputime we spent on the guest */
vtime_account_system(current);
@@ -141,4 +153,22 @@ static inline void guest_exit(void)
}
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */

+static inline void guest_enter(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ guest_enter_irqoff();
+ local_irq_restore(flags);
+}
+
+static inline void guest_exit(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ guest_exit_irqoff();
+ local_irq_restore(flags);
+}
+
#endif
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 1c9c973a7dd9..30c9224545b1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -870,40 +870,23 @@ static inline void kvm_iommu_unmap_pages(struct kvm *kvm,
/* must be called with irqs disabled */
static inline void __kvm_guest_enter(void)
{
- guest_enter();
- /* KVM does not hold any references to rcu protected data when it
- * switches CPU into a guest mode. In fact switching to a guest mode
- * is very similar to exiting to userspace from rcu point of view. In
- * addition CPU may stay in a guest mode for quite a long time (up to
- * one time slice). Lets treat guest mode as quiescent state, just like
- * we do with user-mode execution.
- */
- if (!context_tracking_cpu_is_enabled())
- rcu_virt_note_context_switch(smp_processor_id());
+ guest_enter_irqoff();
}

/* must be called with irqs disabled */
static inline void __kvm_guest_exit(void)
{
- guest_exit();
+ guest_exit_irqoff();
}

static inline void kvm_guest_enter(void)
{
- unsigned long flags;
-
- local_irq_save(flags);
- __kvm_guest_enter();
- local_irq_restore(flags);
+ guest_enter();
}

static inline void kvm_guest_exit(void)
{
- unsigned long flags;
-
- local_irq_save(flags);
- __kvm_guest_exit();
- local_irq_restore(flags);
+ guest_exit();
}

/*
--
1.8.3.1