Re: [Qemu-devel] [PATCH 1/2 v2] pci: change default value of rom_bar to 2

[Bandan Das]

Alex Williamson <address@hidden> writes:

> On Wed, 2014-02-19 at 15:20 -0500, Bandan Das wrote:
>> The following patch depends on the value of rom_bar to
>> determine rom blacklist behavior. Existing code shouldn't
>> be affected by changing the default value of rom_bar since
>> all relevant decisions only rely on whether rom_bar is zero
>> or non-zero.
>> 
>> Signed-off-by: Bandan Das <address@hidden>
>> ---
>>  hw/pci/pci.c | 7 ++++++-
>>  1 file changed, 6 insertions(+), 1 deletion(-)
>> 
>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>> index 4e0701d..12c3e27 100644
>> --- a/hw/pci/pci.c
>> +++ b/hw/pci/pci.c
>> @@ -53,7 +53,12 @@ static void pci_bus_finalize(Object *obj);
>>  static Property pci_props[] = {
>>      DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
>>      DEFINE_PROP_STRING("romfile", PCIDevice, romfile),
>> -    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
>> +    /*
>> +     * 0 = disable
>> +     * 1 = user requested on, force loading even if rom blacklisted
>> +     * 2 = enabled but disables loading of blacklisted roms (default)
>> +     */
>> +    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 2),
>>      DEFINE_PROP_BIT("multifunction", PCIDevice, cap_present,
>>                      QEMU_PCI_CAP_MULTIFUNCTION_BITNR, false),
>>      DEFINE_PROP_BIT("command_serr_enable", PCIDevice, cap_present,
>
> A slightly more satisfying option might be to define rom_bar as int32_t
> with default of -1.  I don't know if that would break libvirt though.
> I'll let MST weigh in.  Thanks,

IMO, since the default is "enabled", having a value of -1 for an enabled
option could be a bit confusing to some.

Bandan

> Alex