Hi Gavin, On 8/15/21 2:59 AM, Gavin Shan wrote: > This adds inline helper kvm_check_async_pf_completion_queue() to > check if there are pending completion in the queue. The empty stub > is also added on !CONFIG_KVM_ASYNC_PF so that the caller needn't > consider if CONFIG_KVM_ASYNC_PF is enabled. > > All checks on the completion queue is done by the newly added inline > function since list_empty() and list_empty_careful() are interchangeable. why is it interchangeable?
> > Signed-off-by: Gavin Shan <[email protected]> > --- > arch/x86/kvm/x86.c | 2 +- > include/linux/kvm_host.h | 10 ++++++++++ > virt/kvm/async_pf.c | 10 +++++----- > virt/kvm/kvm_main.c | 4 +--- > 4 files changed, 17 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index e5d5c5ed7dd4..7f35d9324b99 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -11591,7 +11591,7 @@ static inline bool > kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu) > > static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu) > { > - if (!list_empty_careful(&vcpu->async_pf.done)) > + if (kvm_check_async_pf_completion_queue(vcpu)) > return true; > > if (kvm_apic_has_events(vcpu)) > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 85b61a456f1c..a5f990f6dc35 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -339,12 +339,22 @@ struct kvm_async_pf { > bool notpresent_injected; > }; > > +static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) > +{ > + return !list_empty_careful(&vcpu->async_pf.done); > +} > + > void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu); > void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu); > bool kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, > unsigned long hva, struct kvm_arch_async_pf *arch); > int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu); > #else > +static inline bool kvm_check_async_pf_completion_queue(struct kvm_vcpu *vcpu) > +{ > + return false; > +} > + > static inline void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) { } > #endif > > diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c > index dd777688d14a..d145a61a046a 100644 > --- a/virt/kvm/async_pf.c > +++ b/virt/kvm/async_pf.c > @@ -70,7 +70,7 @@ static void async_pf_execute(struct work_struct *work) > kvm_arch_async_page_present(vcpu, apf); > > spin_lock(&vcpu->async_pf.lock); > - first = list_empty(&vcpu->async_pf.done); > + first = !kvm_check_async_pf_completion_queue(vcpu); > list_add_tail(&apf->link, &vcpu->async_pf.done); > apf->vcpu = NULL; > spin_unlock(&vcpu->async_pf.lock); > @@ -122,7 +122,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu > *vcpu) > spin_lock(&vcpu->async_pf.lock); > } > > - while (!list_empty(&vcpu->async_pf.done)) { > + while (kvm_check_async_pf_completion_queue(vcpu)) { this is replaced by a stronger check. Please can you explain why is it equivalent? > struct kvm_async_pf *work = > list_first_entry(&vcpu->async_pf.done, > typeof(*work), link); > @@ -138,7 +138,7 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu) > { > struct kvm_async_pf *work; > > - while (!list_empty_careful(&vcpu->async_pf.done) && > + while (kvm_check_async_pf_completion_queue(vcpu) && > kvm_arch_can_dequeue_async_page_present(vcpu)) { > spin_lock(&vcpu->async_pf.lock); > work = list_first_entry(&vcpu->async_pf.done, typeof(*work), > @@ -205,7 +205,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) > struct kvm_async_pf *work; > bool first; > > - if (!list_empty_careful(&vcpu->async_pf.done)) > + if (kvm_check_async_pf_completion_queue(vcpu)) > return 0; > > work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC); > @@ -216,7 +216,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu) > INIT_LIST_HEAD(&work->queue); /* for list_del to work */ > > spin_lock(&vcpu->async_pf.lock); > - first = list_empty(&vcpu->async_pf.done); > + first = !kvm_check_async_pf_completion_queue(vcpu); > list_add_tail(&work->link, &vcpu->async_pf.done); > spin_unlock(&vcpu->async_pf.lock); > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index b50dbe269f4b..8795503651b1 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -3282,10 +3282,8 @@ static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu) > if (kvm_arch_dy_runnable(vcpu)) > return true; > > -#ifdef CONFIG_KVM_ASYNC_PF > - if (!list_empty_careful(&vcpu->async_pf.done)) > + if (kvm_check_async_pf_completion_queue(vcpu)) > return true; > -#endif > > return false; > } > Thanks Eric _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
