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authorPaul Mackerras <paulus@ozlabs.org>2018-09-21 13:02:01 +0300
committerPaul Mackerras <paulus@ozlabs.org>2018-10-09 08:14:47 +0300
commitaa069a996951f3e2e38437ef0316685a5893fc7e (patch)
tree40de54d39eeb75cb318b221a3d497a032ca72ab4 /Documentation/virtual/kvm/api.txt
parent9d67121a4fce20e0f7f127d40cd824fbbf5297dc (diff)
downloadlinux-aa069a996951f3e2e38437ef0316685a5893fc7e.tar.xz
KVM: PPC: Book3S HV: Add a VM capability to enable nested virtualization
With this, userspace can enable a KVM-HV guest to run nested guests under it. The administrator can control whether any nested guests can be run; setting the "nested" module parameter to false prevents any guests becoming nested hypervisors (that is, any attempt to enable the nested capability on a guest will fail). Guests which are already nested hypervisors will continue to be so. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'Documentation/virtual/kvm/api.txt')
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diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 2f5f9b743bff..fde48b6708f1 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4532,6 +4532,20 @@ With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise,
a #GP would be raised when the guest tries to access. Currently, this
capability does not enable write permissions of this MSR for the guest.
+7.16 KVM_CAP_PPC_NESTED_HV
+
+Architectures: ppc
+Parameters: none
+Returns: 0 on success, -EINVAL when the implementation doesn't support
+ nested-HV virtualization.
+
+HV-KVM on POWER9 and later systems allows for "nested-HV"
+virtualization, which provides a way for a guest VM to run guests that
+can run using the CPU's supervisor mode (privileged non-hypervisor
+state). Enabling this capability on a VM depends on the CPU having
+the necessary functionality and on the facility being enabled with a
+kvm-hv module parameter.
+
8. Other capabilities.
----------------------