Re: [PATCH v4 12/21] KVM: arm64: Support SDEI_{PRIVATE, SHARED}_RESET hypercall

Eric Auger
2021-11-09T20:37:52Z

On 8/15/21 2:13 AM, Gavin Shan wrote:
> This supports SDEI_{PRIVATE, SHARED}_RESET. They are used by the
> guest to purge the private or shared SDEI events, which are registered
to reset all private SDEI event registrations of the calling PE (resp.
PRIVATE or SHARED)
> previously.
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> arch/arm64/kvm/sdei.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/arch/arm64/kvm/sdei.c b/arch/arm64/kvm/sdei.c
> index 3fb33258b494..62efee2b67b8 100644
> --- a/arch/arm64/kvm/sdei.c
> +++ b/arch/arm64/kvm/sdei.c
> @@ -582,6 +582,29 @@ static unsigned long kvm_sdei_hypercall_mask(struct kvm_vcpu *vcpu,
> return ret;
> }
>
> +static unsigned long kvm_sdei_hypercall_reset(struct kvm_vcpu *vcpu,
> + bool private)
> +{
> + struct kvm *kvm = vcpu->kvm;
> + struct kvm_sdei_kvm *ksdei = kvm->arch.sdei;
> + struct kvm_sdei_vcpu *vsdei = vcpu->arch.sdei;
> + unsigned int mask = private ? (1 << SDEI_EVENT_TYPE_PRIVATE) :
> + (1 << SDEI_EVENT_TYPE_SHARED);
> + unsigned long ret = SDEI_SUCCESS;
> +
> + /* Sanity check */
> + if (!(ksdei && vsdei)) {
> + ret = SDEI_NOT_SUPPORTED;
> + goto out;
> + }
> +
> + spin_lock(&ksdei->lock);
> + kvm_sdei_remove_kvm_events(kvm, mask, false);
With kvm_sdei_remove_kvm_events() implementation, why do you make sure
that events which have a running handler get unregistered once the
handler completes? I just see the refcount check that prevents the "KVM
event object" from being removed.
> + spin_unlock(&ksdei->lock);
> +out:
> + return ret;
> +}
> +
> int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> {
> u32 func = smccc_get_function(vcpu);
> @@ -626,8 +649,14 @@ int kvm_sdei_hypercall(struct kvm_vcpu *vcpu)
> break;
> case SDEI_1_0_FN_SDEI_INTERRUPT_BIND:
> case SDEI_1_0_FN_SDEI_INTERRUPT_RELEASE:
> + ret = SDEI_NOT_SUPPORTED;
> + break;
> case SDEI_1_0_FN_SDEI_PRIVATE_RESET:
> + ret = kvm_sdei_hypercall_reset(vcpu, true);
> + break;
> case SDEI_1_0_FN_SDEI_SHARED_RESET:
> + ret = kvm_sdei_hypercall_reset(vcpu, false);
> + break;
> default:
> ret = SDEI_NOT_SUPPORTED;
> }
>
Eric