Re: [PATCH v4 01/15] hw/pci: Add a pci_setup_iommu_ops() helper

[Joao Martins]

On 02/10/2023 16:12, Cédric Le Goater wrote:
> Hello Joao,
> 
> On 6/22/23 23:48, Joao Martins wrote:
>> From: Yi Liu <yi.l.liu@intel.com>
>>
>> Add a pci_setup_iommu_ops() that uses a newly added structure
>> (PCIIOMMUOps) instead of using PCIIOMMUFunc. The old pci_setup_iommu()
>> that uses PCIIOMMUFunc is still kept for other IOMMUs to get an
>> an address space for a PCI device in vendor specific way.
>>
>> In preparation to expand to supplying vIOMMU attributes, add a
>> alternate helper pci_setup_iommu_ops() to setup the PCI device IOMMU.
>> For now the PCIIOMMUOps just defines the address_space, but it will
>> be extended to have another callback.
>>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> [joao: Massage commit message and subject, and make it a complementary
>> rather than changing every single consumer of pci_setup_iommu()]
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>> v1: https://lore.kernel.org/all/20210302203827.437645-5-yi.l.liu@intel.com/
>> ---
>>   include/hw/pci/pci.h     |  7 +++++++
>>   include/hw/pci/pci_bus.h |  1 +
>>   hw/pci/pci.c             | 26 +++++++++++++++++++++++---
>>   3 files changed, 31 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
>> index e6d0574a2999..f59aef5a329a 100644
>> --- a/include/hw/pci/pci.h
>> +++ b/include/hw/pci/pci.h
>> @@ -368,6 +368,13 @@ typedef AddressSpace *(*PCIIOMMUFunc)(PCIBus *, void *,
>> int);
>>   AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
>>   void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque);
>>   +typedef struct PCIIOMMUOps PCIIOMMUOps;
>> +struct PCIIOMMUOps {
>> +    AddressSpace * (*get_address_space)(PCIBus *bus,
>> +                                void *opaque, int32_t devfn);
>> +};
>> +void pci_setup_iommu_ops(PCIBus *bus, const PCIIOMMUOps *iommu_ops, void
>> *opaque);
>> +
> 
> I think you should first convert all PHBs to PCIIOMMUOps to avoid all the
> tests as below and adapt pci_setup_iommu_ops() with the new parameter.
> 

OK, that's Yi's original patch:

https://lore.kernel.org/all/20210302203827.437645-5-yi.l.liu@intel.com/

I went with this one is that 1) it might take eons to get every single IOMMU
maintainer ack; and 2) it would allow each IOMMU to move at its own speed
specially as I can't test most of the other ones. essentially iterative, rather
than invasive change? Does that make sense?

        Joao