Re: [RFC PATCH v2 0/5] hw/pci, hw/arm/virt: fixed PCI BAR placement

[Tushar Dave <tdave@nvidia.com>]

On 9/3/2026 4:47 AM, Gerd Hoffmann wrote:
>   Hi,
> 
>>> Also note that OVMF already has an incompatible pci device driver and
>>> there can be only one instance, so the code must be merged into the
>>> existing driver instead of adding a second.
>>
>> I checked OvmfPkg/IncompatiblePciDeviceSupportDxe -- its CheckDevice()
>> is unconditional, it returns the same 64-bit-MMIO-preference descriptor
>> for every device regardless of VendorId/DeviceId. Merging Fixed BAR
>> design in would make it a simple dispatch: if the device has an entry in
>> the fw_cfg blob we export, return our descriptor; otherwise fall through
>> to the existing behavior unchanged. Does that match what you had in
>> mind, or is there a different integration point you'd prefer?
> 
> For the most part yes.
> 
> I'd suggest to keep the fixed-bars code in a separate source file,
> then just add a small dispatch hook to the existing CheckDevice
> function.  In case there is a fixed-bars entry use that instead of the
> hardcoded template.
> 
> The option rom tweak for confidential VMs should be applied to the
> fixed-bars entries too, so don't return early.

Okay, thanks. I will incorporate all the changes and send the non-RFC
patch series.

Thanks.
-Tushar
> 
> take care,
>   Gerd