If an Oracle product has been certified against and is supported on a version of Red Hat Enterprise Linux (RHEL), it is automatically certified and supported on the corresponding version of Oracle Linux . For example, RHEL4 -> Oracle Linux 4.
If a product is supported and certified on Oracle Linux or RHEL, it is also certified and supported in the virtualized installation of the same version of Oracle Linux or RHEL running on Oracle Cloud Infrastructure Virtual Machines (VM) or Oracle Linux KVM. For example, Oracle Linux 7 -> Oracle Linux 7 on Oracle VM, Oracle Linux 7 -> Oracle Linux 7 on Oracle KVM, RHEL7 -> RHEL7 on Oracle VM, RHEL 7 -> RHEL7 on Oracle KVM. Oracle recommends using latest update levels and Oracle Linux KVM or Oracle VM versions available.
Every Oracle product that is certified on Windows is also certified and supported when running on Windows virtual guest on Oracle VM or Oracle Linux KVM as long as the release of Windows is supported with Oracle VM or Oracle Linux KVM.
Every Oracle product that is certified on Oracle Solaris is also certified and supported when running on Oracle Solaris virtual guest on Oracle VM as long as the release of Oracle Solaris is supported with Oracle VM.
As per the Oracle Software Technical Support Policies (PDF) document, you must remain on a supported environment—including applications and platforms—to receive technical support. If a vendor retires support for its product, you may be required to upgrade to a current certified and supported product, application, hardware platform, framework, database, and/or operating system configuration to continue receiving technical support services from Oracle.