KVM: Add method to check for backwards-compatible API extensions
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 5d24203..39cf8fd 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -2416,6 +2416,12 @@
r = 0;
break;
}
+ case KVM_CHECK_EXTENSION:
+ /*
+ * No extensions defined at present.
+ */
+ r = 0;
+ break;
default:
;
}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 93472da..c93cf53 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -232,6 +232,11 @@
#define KVM_GET_API_VERSION _IO(KVMIO, 0x00)
#define KVM_CREATE_VM _IO(KVMIO, 0x01) /* returns a VM fd */
#define KVM_GET_MSR_INDEX_LIST _IOWR(KVMIO, 0x02, struct kvm_msr_list)
+/*
+ * Check if a kvm extension is available. Argument is extension number,
+ * return is 1 (yes) or 0 (no, sorry).
+ */
+#define KVM_CHECK_EXTENSION _IO(KVMIO, 0x03)
/*
* ioctls for VM fds