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 <[email protected]> --- arch/s390/kvm/kvm-s390.c | 10 ++++++---- 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 46f37df..c25d4e5 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -2010,12 +2010,14 @@ 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 d12b210..2d3b3ce 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -749,16 +749,10 @@ 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 @@ -769,12 +763,27 @@ 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); } -- 2.3.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
