Re: [PATCH] hw/acpi: Set memory regions to native endian as a work around

[Paolo Bonzini]

On 3/6/23 23:56, Paolo Bonzini wrote:
> On 2/21/23 13:55, BALATON Zoltan wrote:
> > To get that menu with Shut Down, first Quit the installer then again 
> > right click or click on background first to get the menu of the 
> > Ambient desktop. I also see an error from the firmware at the beginning:
> > Initializing KBD...00000012    FAILED.
> > when it's broken and it says Done without the hex number when it 
> > works. (Two other FAILED messages about clock chip is normal as we 
> > don't emulate that but all others should be green.)
>
> Ok, I've reproduced it.  The mouse is a bit flaky but using the keyboard 
> for everything except right clicking works better.

Now the OS doesn't boot anymore, it doesn't get to the point where it 
initializes the VGA.  I got some quick logs with .impl.min_access_size 
to 1, to understand what the firmware (but not the OS) does.  With this 
at least I could confirm that your patch is wrong:

cnt 1 1 write 80
evt 3 1 write 1         // enable timer
evt 0 2 read
evt 0 2 write 1         // just writes again the same value
evt 1 1 write
evt 1 1 write 0

Since you have both 1-size and 2-size writes, and the 2-byte 
reads/writes are done with byte swapping instructions lhbrx and sthbrx, 
your patch would cause 0x100 to be read and written on the third and 
fourth lines.

Likewise, any 4-byte read of the timer port would be byte swapped.

The solution is a patch similar to mine, applied to both evt and cnt; 
while perhaps tmr can be left as is and only accept 4-byte reads, I 
don't know.  I'll try to come up with something that can be tested at 
least with the firmware.

Paolo