Imported OVA with SATA controller unbootable in BIOS mode

[Roman Valov]

Steps to reproduce:

1. Import OVA/OVF template with following entry for disk controller:

<Item>
<rasd:Description>SATA Controller</rasd:Description>
<rasd:Caption>sataController0</rasd:Caption>
<rasd:InstanceID>4</rasd:InstanceID>
<rasd:ResourceType>20</rasd:ResourceType>
<rasd:ResourceSubType>AHCI</rasd:ResourceSubType>
<rasd:Address>0</rasd:Address>
<rasd:BusNumber>0</rasd:BusNumber>
</Item>

2. Try to boot...

Expected:

System booted up.

Actually

Got weird behavior -- on first boot strange error appears, on second boot system freezes after passing GRUB. Sometimes after several reboots system is booted.

Workaround Seems it's similar to #6984.

SATA controller is created with port count equal to 30. If port count is set to 1, system boots up flawlessly.

Also when SATA controlled is removed via VirtualBox UI, and new is one added to the system, it's port count is 0.

Tested with Fedora 30. Screenshot attached.

[Roman Valov]

Guest type: Fedora 30