Re: [Qemu-devel] [PATCH 1/6] ahci: Correct PIO/D2H FIS responses

[Markus Armbruster]

John Snow <address@hidden> writes:

> Currently, the D2H FIS packets AHCI generates simply parrot back
> the LBA that the guest sent to us in the cmd_fis. However, some
> commands (like READ NATIVE MAX) modify the LBA registers as a
> return value, through which the AHCI D2H FIS is the only response
> mechanism. Thus, the D2H response should use the current register
> values, not the initial ones.
>
> This patch adjusts the LBA and drive select register responses for
> PIO Setup and D2H FIS response packets.
>
> Additionally, the PIO and D2H FIS responses copy too many bytes
> from the command FIS that it is being generated from. Specifically,
> byte 11 which is the Features(15:8) field for Register Host to
> Device FIS packets, is instead reserved for the PIO Setup FIS and
> should always be 0.

Ignorant q: is this based on observation or some specification?  If
specification: where can I find a copy?