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sun4u: remap ebus BAR0 to use unassigned_io_ops instead of alias to PCI IO space 

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>
Message-ID: <20240311064345.2531197-1-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
master
Mark Cave-Ayland 2024-03-11 06:43:45 +00:00 committed by Philippe Mathieu-Daudé
parent b691b250d3
commit c1c73b31d9
1 changed files with 7 additions and 2 deletions
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9
hw/sparc64/sun4u.c
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@ -360,8 +360,13 @@ static void ebus_realize(PCIDevice *pci_dev, Error **errp)
pci_dev->config[0x09] = 0x00; // programming i/f
pci_dev->config[0x0D] = 0x0a; // latency_timer
memory_region_init_alias(&s->bar0, OBJECT(s), "bar0",
pci_address_space_io(pci_dev), 0, 0x1000000);
/*
* BAR0 is accessed by OpenBSD but not for ebus device access: allow any
* memory access to this region to succeed which allows the OpenBSD kernel
* to boot.
*/
memory_region_init_io(&s->bar0, OBJECT(s), &unassigned_io_ops, s,
"bar0", 0x1000000);
pci_register_bar(pci_dev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->bar0);
memory_region_init_alias(&s->bar1, OBJECT(s), "bar1",
pci_address_space_io(pci_dev), 0, 0x8000);