Re: [PATCH v3 7/9] context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain

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On 16.04.21 00:21, Sean Christopherson wrote:
Move the guest enter/exit wrappers to kvm_host.h so that KVM can manage
its context tracking vs. vtime accounting without bleeding too many KVM
details into the context tracking code.

No functional change intended.

Funny story. This used to be in kvm code and it was moved to context_tracking by
commit 521921bad1192fb1b8f9b6a5aa673635848b8b5f
    kvm: Move guest entry/exit APIs to context_tracking

I think with all your cleanup it can now move back as it no longer deals with
context tracking.



Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
  include/linux/context_tracking.h | 45 --------------------------------
  include/linux/kvm_host.h         | 45 ++++++++++++++++++++++++++++++++
  2 files changed, 45 insertions(+), 45 deletions(-)

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index e172a547b2d0..d4dc9c4d79aa 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -118,49 +118,4 @@ extern void context_tracking_init(void);
  static inline void context_tracking_init(void) { }
  #endif /* CONFIG_CONTEXT_TRACKING_FORCE */
-/* must be called with irqs disabled */
-static __always_inline void guest_enter_irqoff(void)
-{
-	/*
-	 * This is running in ioctl context so its safe to assume that it's the
-	 * stime pending cputime to flush.
-	 */
-	instrumentation_begin();
-	vtime_account_guest_enter();
-	instrumentation_end();
-
-	/*
-	 * 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_guest_enter_irqoff()) {
-		instrumentation_begin();
-		rcu_virt_note_context_switch(smp_processor_id());
-		instrumentation_end();
-	}
-}
-
-static __always_inline void guest_exit_irqoff(void)
-{
-	context_tracking_guest_exit_irqoff();
-
-	instrumentation_begin();
-	/* Flush the guest cputime we spent on the guest */
-	vtime_account_guest_exit();
-	instrumentation_end();
-}
-
-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 3b06d12ec37e..444d5f0225cb 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -332,6 +332,51 @@ struct kvm_vcpu {
  	struct kvm_dirty_ring dirty_ring;
  };
+/* must be called with irqs disabled */
+static __always_inline void guest_enter_irqoff(void)
+{
+	/*
+	 * This is running in ioctl context so its safe to assume that it's the
+	 * stime pending cputime to flush.
+	 */
+	instrumentation_begin();
+	vtime_account_guest_enter();
+	instrumentation_end();
+
+	/*
+	 * 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_guest_enter_irqoff()) {
+		instrumentation_begin();
+		rcu_virt_note_context_switch(smp_processor_id());
+		instrumentation_end();
+	}
+}
+
+static __always_inline void guest_exit_irqoff(void)
+{
+	context_tracking_guest_exit_irqoff();
+
+	instrumentation_begin();
+	/* Flush the guest cputime we spent on the guest */
+	vtime_account_guest_exit();
+	instrumentation_end();
+}
+
+static inline void guest_exit(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	guest_exit_irqoff();
+	local_irq_restore(flags);
+}
+
  static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu)
  {
  	/*




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