context_tracking: Move guest exit vtime accounting to separate helpers

Provide separate vtime accounting functions for guest exit instead of
open coding the logic within the context tracking code.  This will allow
KVM x86 to handle vtime accounting slightly differently when using
tick-based accounting.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210505002735.1684165-3-seanjc@google.com

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index b8c7313495a7720dab4d949b59014d4d2c9f7b6b..4f4556232dcf7d2c5a957985dd3deca1281004b5 100644 (file)
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -137,15 +137,20 @@ static __always_inline void context_tracking_guest_exit(void)
                __context_tracking_exit(CONTEXT_GUEST);
 }
 
-static __always_inline void guest_exit_irqoff(void)
+static __always_inline void vtime_account_guest_exit(void)
 {
-       context_tracking_guest_exit();
-
-       instrumentation_begin();
        if (vtime_accounting_enabled_this_cpu())
                vtime_guest_exit(current);
        else
                current->flags &= ~PF_VCPU;
+}
+
+static __always_inline void guest_exit_irqoff(void)
+{
+       context_tracking_guest_exit();
+
+       instrumentation_begin();
+       vtime_account_guest_exit();
        instrumentation_end();
 }
 
@@ -166,12 +171,17 @@ static __always_inline void guest_enter_irqoff(void)
 
 static __always_inline void context_tracking_guest_exit(void) { }
 
+static __always_inline void vtime_account_guest_exit(void)
+{
+       vtime_account_kernel(current);
+       current->flags &= ~PF_VCPU;
+}
+
 static __always_inline void guest_exit_irqoff(void)
 {
        instrumentation_begin();
        /* Flush the guest cputime we spent on the guest */
-       vtime_account_kernel(current);
-       current->flags &= ~PF_VCPU;
+       vtime_account_guest_exit();
        instrumentation_end();
 }
 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */