Re: [PATCH v3 01/15] hw/pci: Refactor pci_device_iommu_address_space()

[Joao Martins]

On 30/05/2023 23:04, Philippe Mathieu-Daudé wrote:
> Hi Joao,
> 
> On 30/5/23 19:59, Joao Martins wrote:
>> Rename pci_device_iommu_address_space() into pci_device_iommu_info().
>> In the new function return a new type PCIAddressSpace that encapsulates
>> the AddressSpace pointer that originally was returned.
>>
>> The new type is added in preparation to expanding it to include the IOMMU
>> memory region as a new field, such that we are able to fetch attributes of
>> the vIOMMU e.g. at vfio migration setup.
>>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>>   hw/pci/pci.c         |  9 ++++++---
>>   include/hw/pci/pci.h | 21 ++++++++++++++++++++-
> 
> Please consider using scripts/git.orderfile.
> 
Will do -- wasn't aware of that script.

>>   2 files changed, 26 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
>> index 1cc7c89036b5..ecf8a543aa77 100644
>> --- a/hw/pci/pci.c
>> +++ b/hw/pci/pci.c
>> @@ -2633,11 +2633,12 @@ static void pci_device_class_base_init(ObjectClass
>> *klass, void *data)
>>       }
>>   }
>>   -AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
>> +PCIAddressSpace pci_device_iommu_info(PCIDevice *dev)
>>   {
> 
> This function is PCI specific, ...
> 
>>   }
>>     void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque)
>> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
>> index e6d0574a2999..9ffaf47fe2ab 100644
>> --- a/include/hw/pci/pci.h
>> +++ b/include/hw/pci/pci.h
>> @@ -363,9 +363,28 @@ void pci_bus_get_w64_range(PCIBus *bus, Range *range);
>>     void pci_device_deassert_intx(PCIDevice *dev);
>>   +typedef struct PCIAddressSpace {
>> +    AddressSpace *as;
> 
> ... but here I fail to understand what is PCI specific in this
> structure. You are just trying to an AS with a IOMMU MR, right?
> 
Right. The patch is trying to better split the changes to use one function to
return everything (via pci_device_iommu_info) with the PCIAddressSpace
intermediate structure as retval, such that patch 3 just adds a
IOMMUMemoryRegion* in the latter for usage with the
pci_device_iommu_memory_region().

I've named the structure with a 'PCI' prefix, because it seemed to me that it is
the only case (AIUI) that cares about whether a PCI has a different address
space that the memory map.

>> +} PCIAddressSpace;
>> +
>>   typedef AddressSpace *(*PCIIOMMUFunc)(PCIBus *, void *, int);
>> +static inline PCIAddressSpace as_to_pci_as(AddressSpace *as)
>> +{
>> +    PCIAddressSpace ret = { .as = as };
>> +
>> +    return ret;
>> +}
>> +static inline AddressSpace *pci_as_to_as(PCIAddressSpace pci_as)
>> +{
>> +    return pci_as.as;
>> +}
>> +
>> +PCIAddressSpace pci_device_iommu_info(PCIDevice *dev);
>> +static inline AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
>> +{
>> +    return pci_as_to_as(pci_device_iommu_info(dev));
>> +}
>>   -AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
>>   void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque);
>>     pcibus_t pci_bar_address(PCIDevice *d,
>