Re: [PATCH 4/7] hw/hppa: Inform SeaBIOS about fw_cfg port address

[Helge Deller]

On 01.09.20 23:39, Richard Henderson wrote:
> On 9/1/20 11:34 AM, Helge Deller wrote:
>> -/* QEMU fw_cfg interface port */
>> -#define QEMU_FW_CFG_IO_BASE     (MEMORY_HPA + 0x80)
>> +#define FW_CFG_IO_BASE  0xfffa0000
>
> Why is this value changing?

Devices on hppa occupy at least 4k starting at the HPA,
so MEMORY_HPA+4k is blocked (by Linux) for the memory module.
I noticed this when testing the new Linux kernel patch to
let the fw_cfg entries show up in Linux under /proc:
https://patchwork.kernel.org/patch/11715133/
The Linux kernel driver could not allocate the region for fw_cfg.
This new base address seems to not conflict.

Helge