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| author |   Christian Borntraeger <borntraeger@de.ibm.com> | 2015-04-30 13:43:30 +0200 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2015-05-07 11:28:21 +0200 |
| commit | 0097d12e504b3ce57b68810737ad6a5a64a98c68 (patch) | |
| tree | 806b73a1866d271ebe6ee2e7f9bdca3a73a51d62 | |
| parent | kvmclock: set scheduler clock stable (diff) | |
| download | linux-dev-0097d12e504b3ce57b68810737ad6a5a64a98c68.tar.xz linux-dev-0097d12e504b3ce57b68810737ad6a5a64a98c68.zip | |
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 <borntraeger@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 10 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 27 |
2 files changed, 24 insertions, 13 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 8cd8e7b288c5..2be391bb8557 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -1993,12 +1993,14 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) * As PF_VCPU will be used in fault handler, between * guest_enter and guest_exit should be no uaccess. */ - preempt_disable(); - kvm_guest_enter(); - preempt_enable(); + local_irq_disable(); + __kvm_guest_enter(); + local_irq_enable(); exit_reason = sie64a(vcpu->arch.sie_block, vcpu->run->s.regs.gprs); - kvm_guest_exit(); + local_irq_disable(); + __kvm_guest_exit(); + local_irq_enable(); vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); rc = vcpu_post_run(vcpu, exit_reason); 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); } |