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PCI SATA capability for VirtualBox AHCI HBA

Posted: Thu Dec 31, 2015 7:01 pm
by cmpxchg64
Happy new year everyone,

I have a question regarding the data stored inside the SATA PCI-capability located in the PCI configuration space. According to the spec https://pcisig.com/sites/default/files/ ... _final.pdf the following DWORD contains a BAR and an offset to locate the HBA registers.

The problem is that this thing points to BAR4 which is filled with 16 PortI/O bytes for the PCI IDE DMA interface. The AHCI registers can be found throgh BAR5 w/o problems, but I'd like to know what is the reason behind the SATA capability pointing to IDE stuff, even the HBA reports (as configured) that there is no legacy interface.

cheers,
cmpxchg64

Re: PCI SATA capability for VirtualBox AHCI HBA

Posted: Sat Jan 16, 2016 11:11 am
by shmx
IDE registers for compatibility. If AHCI is initialized (in Global HBA Control registrer 31 bit set) IDE mode will no longer work.