On 8/15/21 2:13 AM, Gavin Shan wrote:
> The injected SDEI event is to send notification to guest. The SDEI
> event might not be needed after it's injected. This introduces API
> to support cancellation on the injected SDEI event if it's not fired
> to the guest yet.
> 
> This mechanism will be needed when we're going to support asynchronous
> page fault.

if we are able to manage the migration of an executing SDEI why can't we
manage the migration of pending SDEIs?

Eric
> 
> Signed-off-by: Gavin Shan <gs...@redhat.com>
> ---
>  arch/arm64/include/asm/kvm_sdei.h |  1 +
>  arch/arm64/kvm/sdei.c             | 49 +++++++++++++++++++++++++++++++
>  2 files changed, 50 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/kvm_sdei.h 
> b/arch/arm64/include/asm/kvm_sdei.h
> index 51087fe971ba..353744c7bad9 100644
> --- a/arch/arm64/include/asm/kvm_sdei.h
> +++ b/arch/arm64/include/asm/kvm_sdei.h
> @@ -126,6 +126,7 @@ int kvm_sdei_register_notifier(struct kvm *kvm, unsigned 
> long num,
>                              kvm_sdei_notifier notifier);
>  int kvm_sdei_inject(struct kvm_vcpu *vcpu,
>                   unsigned long num, bool immediate);
> +int kvm_sdei_cancel(struct kvm_vcpu *vcpu, unsigned long num);
>  void kvm_sdei_deliver(struct kvm_vcpu *vcpu);
>  long kvm_sdei_vm_ioctl(struct kvm *kvm, unsigned long arg);
>  long kvm_sdei_vcpu_ioctl(struct kvm_vcpu *vcpu, unsigned long arg);
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index 7c2789cd1421..4f5a582daa97 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -907,6 +907,55 @@ int kvm_sdei_inject(struct kvm_vcpu *vcpu,
>       return ret;
>  }
>  
> +int kvm_sdei_cancel(struct kvm_vcpu *vcpu, unsigned long num)
> +{
> +     struct kvm *kvm = vcpu->kvm;
> +     struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
> +     struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> +     struct kvm_sdei_kvm_event *kske = NULL;
> +     struct kvm_sdei_vcpu_event *ksve = NULL;
> +     int ret = 0;
> +
> +     if (!(ksdei && vsdei)) {
> +             ret = -EPERM;
> +             goto out;
> +     }
> +
> +     /* Find the vCPU event */
> +     spin_lock(&vsdei->lock);
> +     ksve = kvm_sdei_find_vcpu_event(vcpu, num);
> +     if (!ksve) {
> +             ret = -EINVAL;
> +             goto unlock;
> +     }
> +
> +     /* Event can't be cancelled if it has been delivered */
> +     if (ksve->state.refcount <= 1 &&
> +         (vsdei->critical_event == ksve ||
> +          vsdei->normal_event == ksve)) {
> +             ret = -EINPROGRESS;
> +             goto unlock;
> +     }
> +
> +     /* Free the vCPU event if necessary */
> +     kske = ksve->kske;
> +     ksve->state.refcount--;
> +     if (!ksve->state.refcount) {
> +             list_del(&ksve->link);
> +             kfree(ksve);
> +     }
> +
> +unlock:
> +     spin_unlock(&vsdei->lock);
> +     if (kske) {
> +             spin_lock(&ksdei->lock);
> +             kske->state.refcount--;
> +             spin_unlock(&ksdei->lock);
> +     }
> +out:
> +     return ret;
> +}
> +
>  void kvm_sdei_deliver(struct kvm_vcpu *vcpu)
>  {
>       struct kvm *kvm = vcpu->kvm;
> 

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