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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Michael Tokarev <mjt@tls.msk.ru>,
	Christian Borntraeger <borntraeger@de.ibm.com>
Subject: [PATCH v3 6/9] context_tracking: Consolidate guest enter/exit wrappers
Date: Thu, 15 Apr 2021 15:21:03 -0700
Message-ID: <20210415222106.1643837-7-seanjc@google.com> (raw)
In-Reply-To: <20210415222106.1643837-1-seanjc@google.com>

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: Sean Christopherson <seanjc@google.com>
---
 include/linux/context_tracking.h | 65 ++++++++++++--------------------
 1 file changed, 24 insertions(+), 41 deletions(-)

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 1c05035396ad..e172a547b2d0 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -71,6 +71,19 @@ static inline void exception_exit(enum ctx_state prev_ctx)
 	}
 }
 
+static __always_inline bool context_tracking_guest_enter_irqoff(void)
+{
+	if (context_tracking_enabled())
+		__context_tracking_enter(CONTEXT_GUEST);
+
+	return context_tracking_enabled_this_cpu();
+}
+
+static __always_inline void context_tracking_guest_exit_irqoff(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_irqoff(void) { return false; }
+static inline void context_tracking_guest_exit_irqoff(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_irqoff()) {
 		instrumentation_begin();
 		rcu_virt_note_context_switch(smp_processor_id());
 		instrumentation_end();
 	}
 }
 
-static __always_inline void context_tracking_guest_exit_irqoff(void)
-{
-	if (context_tracking_enabled())
-		__context_tracking_exit(CONTEXT_GUEST);
-}
-
 static __always_inline void guest_exit_irqoff(void)
 {
 	context_tracking_guest_exit_irqoff();
 
-	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_irqoff(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)
 {
-- 
2.31.1.368.gbe11c130af-goog


  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15 22:20 [PATCH v3 0/9] KVM: Fix tick-based accounting for x86 guests Sean Christopherson
2021-04-15 22:20 ` [PATCH v3 1/9] context_tracking: Move guest exit context tracking to separate helpers Sean Christopherson
2021-04-20 18:48   ` Christian Borntraeger
2021-04-21 10:57   ` Frederic Weisbecker
2021-04-15 22:20 ` [PATCH v3 2/9] context_tracking: Move guest exit vtime accounting " Sean Christopherson
2021-04-20 18:48   ` Christian Borntraeger
2021-04-15 22:21 ` [PATCH v3 3/9] KVM: x86: Defer tick-based accounting 'til after IRQ handling Sean Christopherson
2021-04-20 23:14   ` Frederic Weisbecker
2021-04-20 23:26     ` Sean Christopherson
2021-04-21 10:11       ` Frederic Weisbecker
2021-04-21 12:19       ` Frederic Weisbecker
2021-04-28 22:38         ` Sean Christopherson
2021-04-21 10:07   ` Frederic Weisbecker
2021-04-15 22:21 ` [PATCH v3 4/9] sched/vtime: Move vtime accounting external declarations above inlines Sean Christopherson
2021-04-21  7:02   ` Christian Borntraeger
2021-04-15 22:21 ` [PATCH v3 5/9] sched/vtime: Move guest enter/exit vtime accounting to vtime.h Sean Christopherson
2021-04-15 22:21 ` Sean Christopherson [this message]
2021-04-15 22:21 ` [PATCH v3 7/9] context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain Sean Christopherson
2021-04-21  7:10   ` Christian Borntraeger
2021-04-15 22:21 ` [PATCH v3 8/9] KVM: x86: Consolidate guest enter/exit logic to common helpers Sean Christopherson
2021-04-15 22:21 ` [PATCH v3 9/9] KVM: Move instrumentation-safe annotations for enter/exit to x86 code Sean Christopherson
2021-04-21  8:09   ` Christian Borntraeger
2021-04-22 14:38     ` Sven Schnelle
2021-04-23  9:32       ` Vasily Gorbik
2021-04-20 23:33 ` [PATCH v3 0/9] KVM: Fix tick-based accounting for x86 guests Frederic Weisbecker

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