[PATCH v9 15/18] KVM: s390: pv: api documentation for asynchronous destroy

Claudio Imbrenda
2022-03-30T12:37:18Z

Add documentation for the new commands added to the KVM_S390_PV_COMMAND
ioctl.

Signed-off-by: Claudio Imbrenda <imbrenda@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 9f3172376ec3..52ba1c52ae3c 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5010,11 +5010,13 @@ 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
@@ -5027,6 +5029,23 @@ 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
+ subsequent asynchronous teardown. The current protected VM will then
+ resume execution immediately as non-protected. If a protected VM had
+ already been prepared without starting the asynchronous teardown process,
+ this call will fail. In that case, the userspace process should issue a
+ normal KVM_PV_DISABLE.
+
+KVM_PV_ASYNC_DISABLE
+ Tear down the protected VM previously prepared for asynchronous teardown.
+ The resources that had been set aside will be freed asynchronously during
+ the execution of this command.
+ This PV command should ideally be issued by userspace from a separate
+ thread. If a fatal signal is received (or the process terminates
+ naturally), the command will terminate immediately without completing.
+
4.126 KVM_X86_SET_MSR_FILTER
----------------------------

--
2.34.1