Re: [PATCH v11 16/19] KVM: s390: pv: api documentation for asynchronous destroy

[Janosch Frank <frankja@linux.ibm.com>]

On 6/3/22 08:56, Claudio Imbrenda wrote:
> Add documentation for the new commands added to the KVM_S390_PV_COMMAND
> ioctl.
> 
> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
> ---
>   Documentation/virt/kvm/api.rst | 25 ++++++++++++++++++++++---
>   1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
> index 11e00a46c610..97d35b30ce3b 100644
> --- a/Documentation/virt/kvm/api.rst
> +++ b/Documentation/virt/kvm/api.rst
> @@ -5143,11 +5143,13 @@ KVM_PV_ENABLE
>     =====      =============================
>   
>   KVM_PV_DISABLE
> -
>     Deregister the VM from the Ultravisor and reclaim the memory that
>     had been donated to the Ultravisor, making it usable by the kernel
> -  again.  All registered VCPUs are converted back to non-protected
> -  ones.
> +  again. All registered VCPUs are converted back to non-protected
> +  ones. If a previous VM had been prepared for asynchonous teardown
> +  with KVM_PV_ASYNC_DISABLE_PREPARE and not actually torn down with
> +  KVM_PV_ASYNC_DISABLE, it will be torn down in this call together with
> +  the current VM.
>   
>   KVM_PV_VM_SET_SEC_PARMS
>     Pass the image header from VM memory to the Ultravisor in
> @@ -5160,6 +5162,23 @@ KVM_PV_VM_VERIFY
>     Verify the integrity of the unpacked image. Only if this succeeds,
>     KVM is allowed to start protected VCPUs.
>   
> +KVM_PV_ASYNC_DISABLE_PREPARE
> +  Prepare the current protected VM for asynchronous teardown. Most
> +  resources used by the current protected VM will be set aside for a

We should state that leftover UV state needs cleanup, namely secure 
storage and the configuration.