How to disable the not configured ata5, ata6, ata7 and ata8 devices (SATA link down)?

Booting to Ubuntu 13.10 from Parallels Desktop for Mac version 8, having 2 hard drives configured and no CD/DVD drives.

When reviewing the dmesg output for delays (or ways to speed up the boot time), there are ata devices spotted which are not configured in the "Hardware" settings for this virtual machine.

The corresponding dmesg lines:

Code:

[    2.532276] ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 6 ports 3 Gbps 0x3f impl SATA mode
[    2.544849] ata3: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200100 irq 40
[    2.544852] ata4: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200180 irq 40
[    2.544854] ata5: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200200 irq 40
[    2.544856] ata6: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200280 irq 40
[    2.544858] ata7: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200300 irq 40
[    2.544859] ata8: SATA max UDMA/133 abar m8192@0xf0200000 port 0xf0200380 irq 40
...
[    3.514714] ata5: SATA link down (SStatus 0 SControl 300)
[    3.834712] ata6: SATA link down (SStatus 0 SControl 300)
[    4.154728] ata7: SATA link down (SStatus 0 SControl 300)
[    4.474693] ata8: SATA link down (SStatus 0 SControl 300)

How can ata5, ata6, ata7 and ata8 be disabled?

Also pata1 and pata2 can be disabled:

Code:

[    2.313922] ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xe000 irq 14
[    2.313924] ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xe008 irq 15

Could someone please give an example which "Boot Flags" to configure?