[2/4] hw/pci: Introduce an API to set PCI host downstream mr for IOMMU integration

Commit Message

Jason Chien March 7, 2025, 8:39 p.m. UTC

When an IOMMU detects that a PCI host has registered struct PCIIOMMUOps,
it should call pci_setup_iommu_downstream_mr(), which invokes
PCIIOMMUOps.set_downstream_mr() to configure the PCI host's downstream
memory region, directing inbound transactions to the IOMMU.

Signed-off-by: Jason Chien <[e-mail]>
---
 hw/pci/pci.c         | 8 ++++++++
 include/hw/pci/pci.h | 9 +++++++++
 2 files changed, 17 insertions(+)

Patch

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 1d42847ef0..983290ef0b 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2858,6 +2858,14 @@  void pci_device_unset_iommu_device(PCIDevice *dev)
     }
 }
 
+void pci_setup_iommu_downstream_mr(PCIBus *bus, MemoryRegion *mr)
+{
+    assert(bus->iommu_ops);
+    assert(bus->iommu_ops->set_downstream_mr);
+
+    bus->iommu_ops->set_downstream_mr(bus->iommu_opaque, mr);
+}
+
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
 {
     /*
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index fcf648da19..1ad5dc7d9d 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -442,6 +442,15 @@  bool pci_device_set_iommu_device(PCIDevice *dev, HostIOMMUDevice *hiod,
                                  Error **errp);
 void pci_device_unset_iommu_device(PCIDevice *dev);
 
+/**
+ * pci_setup_iommu_downstream_mr: Designate a downstream memory region
+ * for a PCIBus
+ *
+ * @bus: the #PCIBus being updated.
+ * @mr: the designated memory region.
+ */
+void pci_setup_iommu_downstream_mr(PCIBus *bus, MemoryRegion *mr);
+
 /**
  * pci_setup_iommu: Initialize specific IOMMU handlers for a PCIBus
  *