Re: [PATCH v2 4/5] pci: Add pci_for_each_root_bus()

[David Hildenbrand]

On 28.10.21 06:31, Peter Xu wrote:
> Add a helper to loop over each root bus of the system, either the default root
> bus or extended buses like pxb-pcie.
> 
> There're three places that can be rewritten with the pci_for_each_root_bus()
> helper that we just introduced.  De-dup the code.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/arm/virt-acpi-build.c | 31 +++++++++++--------------------
>  hw/i386/acpi-build.c     | 38 ++++++++++----------------------------
>  hw/pci/pci.c             | 26 ++++++++++++++++++++++++++
>  include/hw/pci/pci.h     |  2 ++
>  4 files changed, 49 insertions(+), 48 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 674f902652..adba51f35a 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -264,28 +264,20 @@ struct AcpiIortIdMapping {
>  typedef struct AcpiIortIdMapping AcpiIortIdMapping;
>  
>  /* Build the iort ID mapping to SMMUv3 for a given PCI host bridge */
> -static int
> -iort_host_bridges(Object *obj, void *opaque)
> +static void
> +iort_host_bridges(PCIBus *bus, void *opaque)
>  {
> -    GArray *idmap_blob = opaque;
> -
> -    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
> -        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
> -
> -        if (bus && !pci_bus_bypass_iommu(bus)) {
> -            int min_bus, max_bus;
> +    if (!pci_bus_bypass_iommu(bus)) {
> +        int min_bus, max_bus;
>  
> -            pci_bus_range(bus, &min_bus, &max_bus);
> +        pci_bus_range(bus, &min_bus, &max_bus);
>  
> -            AcpiIortIdMapping idmap = {
> -                .input_base = min_bus << 8,
> -                .id_count = (max_bus - min_bus + 1) << 8,
> -            };
> -            g_array_append_val(idmap_blob, idmap);
> -        }
> +        AcpiIortIdMapping idmap = {
> +            .input_base = min_bus << 8,
> +            .id_count = (max_bus - min_bus + 1) << 8,
> +        };
> +        g_array_append_val((GArray *)opaque, idmap);
>      }
> -
> -    return 0;
>  }
>  
>  static int iort_idmap_compare(gconstpointer a, gconstpointer b)
> @@ -320,8 +312,7 @@ build_iort(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>      if (vms->iommu == VIRT_IOMMU_SMMUV3) {
>          AcpiIortIdMapping next_range = {0};
>  
> -        object_child_foreach_recursive(object_get_root(),
> -                                       iort_host_bridges, smmu_idmaps);
> +        pci_for_each_root_bus(iort_host_bridges, smmu_idmaps);
>  
>          /* Sort the smmu idmap by input_base */
>          g_array_sort(smmu_idmaps, iort_idmap_compare);
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index a76b17ed92..3e50acfe35 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2123,20 +2123,12 @@ insert_scope(PCIBus *bus, PCIDevice *dev, void 
> *opaque)
>  }
>  
>  /* For a given PCI host bridge, walk and insert DMAR scope */
> -static int
> -dmar_host_bridges(Object *obj, void *opaque)
> +static void
> +dmar_host_bridges(PCIBus *bus, void *opaque)
>  {
> -    GArray *scope_blob = opaque;
> -
> -    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
> -        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
> -
> -        if (bus && !pci_bus_bypass_iommu(bus)) {
> -            pci_for_each_device_under_bus(bus, insert_scope, scope_blob);
> -        }
> +    if (!pci_bus_bypass_iommu(bus)) {
> +        pci_for_each_device_under_bus(bus, insert_scope, opaque);
>      }
> -
> -    return 0;
>  }
>  
>  /*
> @@ -2165,8 +2157,7 @@ build_dmar_q35(GArray *table_data, BIOSLinker *linker, 
> const char *oem_id,
>       * Insert scope for each PCI bridge and endpoint device which
>       * is attached to a bus with iommu enabled.
>       */
> -    object_child_foreach_recursive(object_get_root(),
> -                                   dmar_host_bridges, scope_blob);
> +    pci_for_each_root_bus(dmar_host_bridges, scope_blob);
>  
>      assert(iommu);
>      if (x86_iommu_ir_supported(iommu)) {
> @@ -2329,20 +2320,12 @@ insert_ivhd(PCIBus *bus, PCIDevice *dev, void *opaque)
>  }
>  
>  /* For all PCI host bridges, walk and insert IVHD entries */
> -static int
> -ivrs_host_bridges(Object *obj, void *opaque)
> +static void
> +ivrs_host_bridges(PCIBus *bus, void *opaque)
>  {
> -    GArray *ivhd_blob = opaque;
> -
> -    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
> -        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
> -
> -        if (bus && !pci_bus_bypass_iommu(bus)) {
> -            pci_for_each_device_under_bus(bus, insert_ivhd, ivhd_blob);
> -        }
> +    if (!pci_bus_bypass_iommu(bus)) {
> +        pci_for_each_device_under_bus(bus, insert_ivhd, opaque);
>      }
> -
> -    return 0;
>  }
>  
>  static void
> @@ -2380,8 +2363,7 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, 
> const char *oem_id,
>       * blob further below.  Fall back to an entry covering all devices, which
>       * is sufficient when no aliases are present.
>       */
> -    object_child_foreach_recursive(object_get_root(),
> -                                   ivrs_host_bridges, ivhd_blob);
> +    pci_for_each_root_bus(ivrs_host_bridges, ivhd_blob);
>  
>      if (!ivhd_blob->len) {
>          /*
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 4a84e478ce..258290f4eb 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2097,6 +2097,32 @@ void pci_for_each_bus_depth_first(PCIBus *bus, 
> pci_bus_ret_fn begin,
>      }
>  }
>  
> +typedef struct {
> +    pci_bus_fn fn;
> +    void *opaque;
> +} PCIRootBusArgs;
> +
> +static int pci_find_root_bus(Object *obj, void *opaque)
> +{
> +    PCIRootBusArgs *args = opaque;
> +    PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
> +
> +    if (bus) {
> +        args->fn(bus, args->opaque);
> +    }
> +
> +    return 0;
> +}
> +
> +void pci_for_each_root_bus(pci_bus_fn fn, void *opaque)
> +{
> +    PCIRootBusArgs args = { .fn = fn, .opaque = opaque };
> +
> +    object_child_foreach_recursive_type(object_get_root(),
> +                                        TYPE_PCI_HOST_BRIDGE,
> +                                        pci_find_root_bus,
> +                                        &args);
> +}
>  
>  PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
>  {
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 5c4016b995..6813f128e0 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -474,6 +474,8 @@ void pci_for_each_device_under_bus_reverse(PCIBus *bus,
>                                             void *opaque);
>  void pci_for_each_bus_depth_first(PCIBus *bus, pci_bus_ret_fn begin,
>                                    pci_bus_fn end, void *parent_state);
> +/* Call `fn' for each pci root bus on the system */
> +void pci_for_each_root_bus(pci_bus_fn fn, void *opaque);
>  PCIDevice *pci_get_function_0(PCIDevice *pci_dev);
>  
>  /* Use this wrapper when specific scan order is not required. */
> 

LGTM

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb