Commit 1ca0016c authored by Sean Christopherson's avatar Sean Christopherson Committed by Thomas Gleixner
Browse files

context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain 



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.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210505002735.1684165-8-seanjc@google.com
parent 14296e0c

include/linux/context_tracking.h

+0 −45
Original line number Diff line number Diff line
@@ -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()) {

		instrumentation_begin();

		rcu_virt_note_context_switch(smp_processor_id());

		instrumentation_end();

	}

}



static __always_inline void guest_exit_irqoff(void)

{

	context_tracking_guest_exit();



	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

include/linux/kvm_host.h

+45 −0
Original line number Diff line number Diff line
@@ -338,6 +338,51 @@ 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()) {

		instrumentation_begin();

		rcu_virt_note_context_switch(smp_processor_id());

		instrumentation_end();

	}

}



static __always_inline void guest_exit_irqoff(void)

{

	context_tracking_guest_exit();



	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)

{

	/*