Re: [PATCH] sun4u: remap ebus BAR0 to use unassigned_io_ops instead of alias to PCI IO space

[Philippe Mathieu-Daudé]

On 11/3/24 07:43, Mark Cave-Ayland wrote:
> During kernel startup OpenBSD accesses addresses mapped by BAR0 of the ebus 
> device
> but at offsets where no IO devices exist. Before commit 4aa07e8649 
> ("hw/sparc64/ebus:
> Access memory regions via pci_address_space_io()") BAR0 was mapped to legacy IO
> space which allows accesses to unmapped devices to succeed, but afterwards these
> accesses to unmapped PCI IO space cause a memory fault which prevents OpenBSD 
> from
> booting.
>
> Since no devices are mapped at the addresses accessed by OpenBSD, change ebus 
> BAR0
> from a PCI IO space alias to an IO memory region using unassigned_io_ops which 
> allows
> these accesses to succeed and so allows OpenBSD to boot once again.
>
> Fixes: 4aa07e8649 ("hw/sparc64/ebus: Access memory regions via 
> pci_address_space_io()")
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> ---
>
> [MCA: I'd like to merge this for 9.0 since I've been carrying various local 
> workarounds
> to allow OpenBSD to boot on SPARC64 for some time.]

Sure.

>   hw/sparc64/sun4u.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)