[PATCH v4.1 36/36] KVM: s390: protvirt: Add KVM api documentation

Christian Borntraeger
2020-02-27T08:47:23Z

From: Janosch Frank <frankja@linux.ibm.com>

Add documentation for KVM_CAP_S390_PROTECTED capability and the
KVM_S390_PV_COMMAND ioctl.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
Documentation/virt/kvm/api.rst | 59 ++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 7505d7a6c0d8..bae90f3cd11d 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -4648,6 +4648,54 @@ the clear cpu reset definition in the POP. However, the cpu is not put
into ESA mode. This reset is a superset of the initial reset.

+4.125 KVM_S390_PV_COMMAND
+-------------------------
+
+:Capability: KVM_CAP_S390_PROTECTED
+:Architectures: s390
+:Type: vm ioctl
+:Parameters: struct kvm_pv_cmd
+:Returns: 0 on success, < 0 on error
+
+::
+
+ struct kvm_pv_cmd {
+ __u32 cmd; /* Command to be executed */
+ __u16 rc; /* Ultravisor return code */
+ __u16 rrc; /* Ultravisor return reason code */
+ __u64 data; /* Data or address */
+ __u32 flags; /* flags for future extensions. Must be 0 for now */
+ __u32 reserved[3];
+ };
+
+cmd values:
+
+KVM_PV_ENABLE
+ Allocate memory and register the VM with the Ultravisor, thereby
+ donating memory to the Ultravisor that will become inaccessible to
+ KVM. All existing CPUs are converted to protected ones. After this
+ command has succeeded, any CPU added via hotplug will become
+ protected during its creation as well.
+
+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.
+
+KVM_PV_VM_SET_SEC_PARMS
+ Pass the image header from VM memory to the Ultravisor in
+ preparation of image unpacking and verification.
+
+KVM_PV_VM_UNPACK
+ Unpack (protect and decrypt) a page of the encrypted boot image.
+
+KVM_PV_VM_VERIFY
+ Verify the integrity of the unpacked image. Only if this succeeds,
+ KVM is allowed to start protected VCPUs.
+
+
5. The kvm_run structure
========================

@@ -6026,3 +6074,14 @@ Architectures: s390

This capability indicates that the KVM_S390_NORMAL_RESET and
KVM_S390_CLEAR_RESET ioctls are available.
+
+8.23 KVM_CAP_S390_PROTECTED
+
+Architecture: s390
+
+
+This capability indicates that the Ultravisor has been initialized and
+KVM can therefore start protected VMs.
+This capability governs the KVM_S390_PV_COMMAND ioctl and the
+KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected
+guests when the state change is invalid.
--
2.25.0