[RFC v2 07/22] hw/pci: introduce pci_device_iommu_context()

[Liu Yi L <yi.l.liu@xxxxxxxxx>]

This patch adds pci_device_iommu_context() to get an iommu_context
for a given device. A new callback is added in PCIIOMMUOps. Users
who wants to listen to events issued by vIOMMU could use this new
interface to get an iommu_context and register their own notifiers,
then wait for notifications from vIOMMU. e.g. VFIO is the first user
of it to listen to the PASID_ALLOC/PASID_BIND/CACHE_INV events and
propagate the events to host.

Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Eric Auger <eric.auger@xxxxxxxxxx>
Cc: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
---
 hw/pci/pci.c         | 16 ++++++++++++++++
 include/hw/pci/pci.h |  5 +++++
 2 files changed, 21 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index b5ce9ca..4e6af06 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2625,6 +2625,22 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
     return &address_space_memory;
 }
 
+IOMMUContext *pci_device_iommu_context(PCIDevice *dev)
+{
+    PCIBus *bus = pci_get_bus(dev);
+    PCIBus *iommu_bus = bus;
+
+    while (iommu_bus && !iommu_bus->iommu_ops && iommu_bus->parent_dev) {
+        iommu_bus = pci_get_bus(iommu_bus->parent_dev);
+    }
+    if (iommu_bus && iommu_bus->iommu_ops &&
+        iommu_bus->iommu_ops->get_iommu_context) {
+        return iommu_bus->iommu_ops->get_iommu_context(bus,
+                           iommu_bus->iommu_opaque, dev->devfn);
+    }
+    return NULL;
+}
+
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
 {
     bus->iommu_ops = ops;
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index d9fed8d..ccada47 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -9,6 +9,8 @@
 
 #include "hw/pci/pcie.h"
 
+#include "hw/iommu/iommu.h"
+
 extern bool pci_available;
 
 /* PCI bus */
@@ -484,9 +486,12 @@ typedef struct PCIIOMMUOps PCIIOMMUOps;
 struct PCIIOMMUOps {
     AddressSpace * (*get_address_space)(PCIBus *bus,
                                 void *opaque, int32_t devfn);
+    IOMMUContext * (*get_iommu_context)(PCIBus *bus,
+                                void *opaque, int32_t devfn);
 };
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
+IOMMUContext *pci_device_iommu_context(PCIDevice *dev);
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *iommu_ops, void *opaque);
 
 static inline void
-- 
2.7.4