Hi Zhenzhong,
On 6/20/25 9:17 AM, Zhenzhong Duan wrote:
> Returns true if PCI device is aliased or false otherwise. This will be
> used in following patch to determine if a PCI device is under a PCI
> bridge.
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
> include/hw/pci/pci.h | 2 ++
> hw/pci/pci.c | 12 ++++++++----
> 2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 829757b2c2..3029cdf26f 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -640,6 +640,8 @@ typedef struct PCIIOMMUOps {
> bool is_write);
> } PCIIOMMUOps;
>
> +bool pci_device_get_iommu_bus_devfn(PCIDevice *dev, PCIBus **piommu_bus,
> + PCIBus **aliased_bus, int *aliased_devfn);
if I am correct you have a single caller of the helper using the
returned value, in intel_iommu.c, whereas all the existing callers are
not using the returned value. You may simply pass a non NULL aliased_bus
and aliased_devfn and check whether they differ from the original
bus/devfn. Besides the patch looks ok to me.
Thanks
Eric
> AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
> bool pci_device_set_iommu_device(PCIDevice *dev, HostIOMMUDevice *hiod,
> Error **errp);
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index df1fb615a8..87f7c942b3 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2857,20 +2857,21 @@ static void pci_device_class_base_init(ObjectClass *klass, const void *data)
> * For call sites which don't need aliased BDF, passing NULL to
> * aliased_[bus|devfn] is allowed.
> *
> + * Returns true if PCI device is aliased or false otherwise.
> + *
> * @piommu_bus: return root #PCIBus backed by an IOMMU for the PCI device.
> *
> * @aliased_bus: return aliased #PCIBus of the PCI device, optional.
> *
> * @aliased_devfn: return aliased devfn of the PCI device, optional.
> */
> -static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
> - PCIBus **piommu_bus,
> - PCIBus **aliased_bus,
> - int *aliased_devfn)
> +bool pci_device_get_iommu_bus_devfn(PCIDevice *dev, PCIBus **piommu_bus,
> + PCIBus **aliased_bus, int *aliased_devfn)
> {
> PCIBus *bus = pci_get_bus(dev);
> PCIBus *iommu_bus = bus;
> int devfn = dev->devfn;
> + bool aliased = false;
>
> while (iommu_bus && !iommu_bus->iommu_ops && iommu_bus->parent_dev) {
> PCIBus *parent_bus = pci_get_bus(iommu_bus->parent_dev);
> @@ -2907,6 +2908,7 @@ static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
> devfn = parent->devfn;
> bus = parent_bus;
> }
> + aliased = true;
> }
>
> iommu_bus = parent_bus;
> @@ -2928,6 +2930,8 @@ static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
> if (aliased_devfn) {
> *aliased_devfn = devfn;
> }
> +
> + return aliased;
> }
>
> AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)