Re: [Qemu-devel] [PATCH v2] piix: fix 32bit pci hole

[Laszlo Ersek <lersek@redhat.com>]

On 11/28/13 17:03, Laszlo Ersek wrote:
> Mike,
> 
> On 11/27/13 12:57, Gerd Hoffmann wrote:
>> Make the 32bit pci hole start at end of ram, so all possible address
>> space is covered.  Of course the firmware can use less than that.
>> Leaving space unused is no problem, mapping pci bars outside the
>> hole causes problems though.
>>
>> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>> ---
>>  hw/pci-host/piix.c | 10 +---------
>>  1 file changed, 1 insertion(+), 9 deletions(-)
>>
>> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
>> index edc974e..8e41ac1 100644
>> --- a/hw/pci-host/piix.c
>> +++ b/hw/pci-host/piix.c
>> @@ -345,15 +345,7 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
>>      f->ram_memory = ram_memory;
>>  
>>      i440fx = I440FX_PCI_HOST_BRIDGE(dev);
>> -    /* Set PCI window size the way seabios has always done it. */
>> -    /* Power of 2 so bios can cover it with a single MTRR */
>> -    if (ram_size <= 0x80000000) {
>> -        i440fx->pci_info.w32.begin = 0x80000000;
>> -    } else if (ram_size <= 0xc0000000) {
>> -        i440fx->pci_info.w32.begin = 0xc0000000;
>> -    } else {
>> -        i440fx->pci_info.w32.begin = 0xe0000000;
>> -    }
>> +    i440fx->pci_info.w32.begin = pci_hole_start;
>>  
>>      memory_region_init_alias(&f->pci_hole, OBJECT(d), "pci-hole", f->pci_address_space,
>>                               pci_hole_start, pci_hole_size);
>>
> 
> please pick this up for 1.7.1.
> 
> 1.7.0 has been released without this patch, also without etc/pci-info,
> but with etc/acpi/tables.
> 
> For OVMF to work with "etc/acpi/tables" correctly, with eg. a guest RAM
> size of 2560MB, OVMF needs:
> - either this patch in qemu, or
> - etc/pci-info (which won't come back), or
> - a hack in OVMF that mimicks the same 0x80000000/0xc0000000/0xe0000000
>   logic (which I won't add).

Nominating this for v1.7.1 again.

The qemu-2.0 version (ie. a forward-port) of this patch has been merged as

  ddaaefb piix: fix 32bit pci hole

If necessary I can resubmit the v1.7.1 patch.

Thanks,
Laszlo