[RFC v11 05/25] hw/pci: introduce pci_device_get_iommu_attr()

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

This patch adds pci_device_get_iommu_attr() to get vIOMMU attributes.
e.g. if nesting IOMMU wanted.

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>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
---
 hw/pci/pci.c         | 35 ++++++++++++++++++++++++++++++-----
 include/hw/pci/pci.h |  7 +++++++
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 61f115d742..19365e2799 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2665,7 +2665,8 @@ static void pci_device_class_base_init(ObjectClass *klass, void *data)
     }
 }
 
-AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
+static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
+                              PCIBus **pbus, uint8_t *pdevfn)
 {
     PCIBus *bus = pci_get_bus(dev);
     PCIBus *iommu_bus = bus;
@@ -2716,14 +2717,38 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
 
         iommu_bus = parent_bus;
     }
-    if (iommu_bus && iommu_bus->iommu_ops &&
-                     iommu_bus->iommu_ops->get_address_space) {
-        return iommu_bus->iommu_ops->get_address_space(bus,
-                                 iommu_bus->iommu_opaque, devfn);
+    *pbus = iommu_bus;
+    *pdevfn = devfn;
+}
+
+AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
+{
+    PCIBus *bus;
+    uint8_t devfn;
+
+    pci_device_get_iommu_bus_devfn(dev, &bus, &devfn);
+    if (bus && bus->iommu_ops &&
+        bus->iommu_ops->get_address_space) {
+        return bus->iommu_ops->get_address_space(bus,
+                                bus->iommu_opaque, devfn);
     }
     return &address_space_memory;
 }
 
+int pci_device_get_iommu_attr(PCIDevice *dev, IOMMUAttr attr, void *data)
+{
+    PCIBus *bus;
+    uint8_t devfn;
+
+    pci_device_get_iommu_bus_devfn(dev, &bus, &devfn);
+    if (bus && bus->iommu_ops &&
+        bus->iommu_ops->get_iommu_attr) {
+        return bus->iommu_ops->get_iommu_attr(bus, bus->iommu_opaque,
+                                               devfn, attr, data);
+    }
+    return -ENOENT;
+}
+
 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 d6b962f646..b99e05c81e 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -485,13 +485,20 @@ void pci_bus_get_w64_range(PCIBus *bus, Range *range);
 
 void pci_device_deassert_intx(PCIDevice *dev);
 
+typedef enum IOMMUAttr {
+    IOMMU_WANT_NESTING,
+} IOMMUAttr;
+
 typedef struct PCIIOMMUOps PCIIOMMUOps;
 struct PCIIOMMUOps {
     AddressSpace * (*get_address_space)(PCIBus *bus,
                                 void *opaque, int32_t devfn);
+    int (*get_iommu_attr)(PCIBus *bus, void *opaque, int32_t devfn,
+                           IOMMUAttr attr, void *data);
 };
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
+int pci_device_get_iommu_attr(PCIDevice *dev, IOMMUAttr attr, void *data);
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *iommu_ops, void *opaque);
 
 static inline void
-- 
2.25.1