Commit 14296e0c authored by Sean Christopherson's avatar Sean Christopherson Committed by Thomas Gleixner
Browse files

context_tracking: Consolidate guest enter/exit wrappers 



Consolidate the guest enter/exit wrappers, providing and tweaking stubs
as needed.  This will allow moving the wrappers under KVM without having
to bleed #ifdefs into the soon-to-be KVM 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/20210505002735.1684165-7-seanjc@google.com
parent 6f922b89

include/linux/context_tracking.h

+24 −41
Original line number Diff line number Diff line
@@ -71,6 +71,19 @@ static inline void exception_exit(enum ctx_state prev_ctx) 
	}

}



static __always_inline bool context_tracking_guest_enter(void)

{

	if (context_tracking_enabled())

		__context_tracking_enter(CONTEXT_GUEST);



	return context_tracking_enabled_this_cpu();

}



static __always_inline void context_tracking_guest_exit(void)

{

	if (context_tracking_enabled())

		__context_tracking_exit(CONTEXT_GUEST);

}



/**

 * ct_state() - return the current context tracking state if known
@@ -92,6 +105,9 @@ static inline void user_exit_irqoff(void) { } 
static inline enum ctx_state exception_enter(void) { return 0; }

static inline void exception_exit(enum ctx_state prev_ctx) { }

static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }

static inline bool context_tracking_guest_enter(void) { return false; }

static inline void context_tracking_guest_exit(void) { }



#endif /* !CONFIG_CONTEXT_TRACKING */



#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
@@ -102,74 +118,41 @@ extern void context_tracking_init(void); 
static inline void context_tracking_init(void) { }

#endif /* CONFIG_CONTEXT_TRACKING_FORCE */





#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN

/* 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();

	if (vtime_accounting_enabled_this_cpu())

		vtime_guest_enter(current);

	else

		current->flags |= PF_VCPU;

	vtime_account_guest_enter();

	instrumentation_end();



	if (context_tracking_enabled())

		__context_tracking_enter(CONTEXT_GUEST);



	/* KVM does not hold any references to rcu protected data when it

	/*

	 * 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_enabled_this_cpu()) {

	if (!context_tracking_guest_enter()) {

		instrumentation_begin();

		rcu_virt_note_context_switch(smp_processor_id());

		instrumentation_end();

	}

}



static __always_inline void context_tracking_guest_exit(void)

{

	if (context_tracking_enabled())

		__context_tracking_exit(CONTEXT_GUEST);

}



static __always_inline void guest_exit_irqoff(void)

{

	context_tracking_guest_exit();



	instrumentation_begin();

	vtime_account_guest_exit();

	instrumentation_end();

}



#else

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();

	rcu_virt_note_context_switch(smp_processor_id());

	instrumentation_end();

}



static __always_inline void context_tracking_guest_exit(void) { }



static __always_inline void guest_exit_irqoff(void)

{

	instrumentation_begin();

	/* Flush the guest cputime we spent on the guest */

	vtime_account_guest_exit();

	instrumentation_end();

}

#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */



static inline void guest_exit(void)

{