+ /* Most hypervisors only have information in leaf 0x40000000.
+ *
+ * Some hypervisors have "Viridian [HyperV] extensions", and those
+ * must appear in slot 0x40000000, but they will also have the true
+ * hypervisor in a higher slot.
+ *
+ * CPUID is supposed to return the maximum leaf offset in %eax, but
+ * this is not reliable. Instead we check the returned signatures
+ * against a known list (the others will be empty or garbage) and
+ * only print the ones we know about. This is OK because if we add
+ * a new test in virt-what we can update the list.
+ *
+ * By searching backwards we only print the highest entry, thus
+ * ignoring Viridian for Xen (and Nutanix). If we ever encounter a
+ * hypervisor that has more than 2 entries we may need to revisit
+ * this.