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authorPaolo Bonzini <pbonzini@redhat.com>2016-06-15 15:09:28 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2016-06-28 14:15:25 +0200
commitebaac1736245e78109cd47d453a86a18dcfc94b8 (patch)
treea3c5e049e0ee9345316f538ccc1acc19b0edbfe1 /include/linux/context_tracking.h
parentfb6cec1492d6a693d33224487061e92d0275c6e2 (diff)
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context_tracking: move rcu_virt_note_context_switch out of kvm_host.h
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: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/linux/context_tracking.h')
-rw-r--r--include/linux/context_tracking.h38
1 files changed, 34 insertions, 4 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index d259274238db..ff4a32d24d56 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -84,7 +84,8 @@ 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);
@@ -93,9 +94,19 @@ 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);
@@ -107,7 +118,7 @@ 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
@@ -116,9 +127,10 @@ 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);
@@ -126,4 +138,22 @@ 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