[BUG]Add PCIE devie to SMMUv3 fail

[sisyphean <sisyphean@zlw.email>]

Hi,

I try to run XEN on my ARM board(Sorry, for some commercial reasons, I 
can't tell you
on which platform I run XEN)  and add PCIE device passthrough to 
DomU.But an error
occurred while adding the PCIE device to SMMUv3.

Through reading the code and tracing debugging, the error is found in 
the function
arm_smmu_add_device, which will obtain and determine whether the fwspec 
of the
device to be added to SMMU exists.But for the XEN of arm, the fwspec of 
the device is
created and added by judging whether the iommu field exists in the 
device node when
XEN parses the device tree.However, the PCIE device does not appear in 
the device tree,
so there will be no fwspec for all PCIE devices. When attempting to add 
a PCIE device to
SMMU, a ENODEV error will be returned.

In addition, the code at xen/drivers/passthrough/pci.c also verifies the 
above view.
For PCIE devices, pdev is alloc in function pci_add_device by 
alloc_pdev.However,
the function alloc_pdev does not create and add fwspec to the PCIE 
device.Therefore,
when function pci_add_device executes to iommu_add_device,it will get 
the error
return of ENODEV.

How can I resolve the above errors?

The XEN version I am running is RELEASE-4.16.2.

English is not my native language; please excuse typing errors.

Cheers,

--
Sisyphean