From 0097d12e504b3ce57b68810737ad6a5a64a98c68 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Thu, 30 Apr 2015 13:43:30 +0200 Subject: KVM: provide irq_unsafe kvm_guest_{enter|exit} Several kvm architectures disable interrupts before kvm_guest_enter. kvm_guest_enter then uses local_irq_save/restore to disable interrupts again or for the first time. Lets provide underscore versions of kvm_guest_{enter|exit} that assume being called locked. kvm_guest_enter now disables interrupts for the full function and thus we can remove the check for preemptible. This patch then adopts s390/kvm to use local_irq_disable/enable calls which are slighty cheaper that local_irq_save/restore and call these new functions. Signed-off-by: Christian Borntraeger Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index ad45054309a0..efc16df1fc5d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -762,16 +762,10 @@ static inline void kvm_iommu_unmap_pages(struct kvm *kvm, } #endif -static inline void kvm_guest_enter(void) +/* must be called with irqs disabled */ +static inline void __kvm_guest_enter(void) { - unsigned long flags; - - BUG_ON(preemptible()); - - local_irq_save(flags); guest_enter(); - local_irq_restore(flags); - /* 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 @@ -783,12 +777,27 @@ static inline void kvm_guest_enter(void) rcu_virt_note_context_switch(smp_processor_id()); } +/* must be called with irqs disabled */ +static inline void __kvm_guest_exit(void) +{ + guest_exit(); +} + +static inline void kvm_guest_enter(void) +{ + unsigned long flags; + + local_irq_save(flags); + __kvm_guest_enter(); + local_irq_restore(flags); +} + static inline void kvm_guest_exit(void) { unsigned long flags; local_irq_save(flags); - guest_exit(); + __kvm_guest_exit(); local_irq_restore(flags); } -- cgit v1.2.3