KVM: PPC: Book3S: Allow only implemented hcalls to be enabled or disabled

This adds code to check that when the KVM_CAP_PPC_ENABLE_HCALL
capability is used to enable or disable in-kernel handling of an
hcall, that the hcall is actually implemented by the kernel.
If not an EINVAL error is returned.

This also checks the default-enabled list of hcalls and prints a
warning if any hcall there is not actually implemented.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 5c54d196f4c8..69553183ef0f 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3039,3 +3039,7 @@ not to attempt to handle the hcall, but will always exit to userspace
 to handle it.  Note that it may not make sense to enable some and
 disable others of a group of related hcalls, but KVM does not prevent
 userspace from doing that.
+
+If the hcall number specified is not one that has an in-kernel
+implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL
+error.