Re: [edk2-devel] [PATCH v4 7/9] OvmfPkg/PciHostBridgeUtilityLib: Extend parameter list of GetRootBridges

["Jiahui Cen" <cenjiahui@huawei.com>]

Hi Laszlo,

On 2021/1/14 18:46, Laszlo Ersek wrote:
>> @@ -124,6 +132,10 @@ PciHostBridgeUtilityGetRootBridges (
>>    UINTN                    *Count,
>>    UINT64                   Attributes,
>>    UINT64                   AllocationAttributes,
>> +  BOOLEAN                  DmaAbove4G,
>> +  BOOLEAN                  NoExtendedConfigSpace,
>> +  UINT32                   BusMin,
>> +  UINT32                   BusMax,
>>    PCI_ROOT_BRIDGE_APERTURE *Io,
>>    PCI_ROOT_BRIDGE_APERTURE *Mem,
>>    PCI_ROOT_BRIDGE_APERTURE *MemAbove4G,
> (1) You forgot to annotate the new params with IN. (Also update the C
> file please, in sync.)
> 
> (2) The BusMin / BusMax addition must absolutely be a separate patch, so
> that we can discuss and review it separately. It's not a simple data
> propagation change -- it generalizes the function internally.
> 
> (3) BusMax should be documented as an inclusive maximum (but see more on
> this below).

A little bit confused. IIUC, the original hard-coded bus ranges, from 0 to
PCI_MAX_BUS, are inclusive, as PCI_MAX_BUS = 255. So in my opinion, the
addition of BusMin/BusMax simply extends the parameters, like DmaAbove4G
and NoExtendedConfigSpace, and replaces [0, PCI_MAX_BUS] with [BusMin, BusMax].
Please correct me if I misunderstand.

Does it really generalize the function?

Thanks,
Jiahui