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

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, May 31, 2023 at 11:03:23AM +0100, Joao Martins wrote:
> 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.


yea keep that pls. It should be possible to figure out the header
from the name.

> >> +} 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,
> >