In VFIO core, we call iommufd_backend_get_device_info() to return vendor
specific hardware information data, but it's not good to retrieve this raw
data in VFIO core.

Introduce a new PCIIOMMUOps optional callback, get_host_iommu_quirk() which
allows to retrieve the vendor specific hardware information data and convert
it into bitmaps defined with enum host_iommu_quirks.

pci_device_get_host_iommu_quirks() is a wrapper that can be called on a PCI
device potentially protected by a vIOMMU.

Suggested-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 include/hw/iommu.h   |  5 +++++
 include/hw/pci/pci.h | 31 +++++++++++++++++++++++++++++++
 hw/pci/pci.c         | 12 ++++++++++++
 3 files changed, 48 insertions(+)

diff --git a/include/hw/iommu.h b/include/hw/iommu.h
index 9b8bb94fc2..6d61410703 100644
--- a/include/hw/iommu.h
+++ b/include/hw/iommu.h
@@ -22,4 +22,9 @@ enum viommu_flags {
     VIOMMU_FLAG_WANT_NESTING_PARENT = BIT_ULL(0),
 };
 
+/* Host IOMMU quirks. Extracted from host IOMMU capabilities */
+enum host_iommu_quirks {
+    HOST_IOMMU_QUIRK_NESTING_PARENT_BYPASS_RO = BIT_ULL(0),
+};
+
 #endif /* HW_IOMMU_H */
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index a3ca54859c..83dc995cf3 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -474,6 +474,23 @@ typedef struct PCIIOMMUOps {
      * enum viommu_flags.
      */
     uint64_t (*get_viommu_flags)(void *opaque);
+    /**
+     * @get_host_iommu_quirks: get host IOMMU quirks
+     *
+     * Optional callback, if not implemented, then vIOMMU doesn't support
+     * converting @type specific hardware information data into a standard
+     * bitmap format.
+     *
+     * @type: IOMMU hardware info type
+     *
+     * @caps: IOMMU @type specific hardware information data
+     *
+     * @size: size of @caps
+     *
+     * Returns: bitmap with each bit representing a host IOMMU quirk defined in
+     * enum host_iommu_quirks
+     */
+    uint64_t (*get_host_iommu_quirks)(uint32_t type, void *caps, uint32_t size);
     /**
      * @get_iotlb_info: get properties required to initialize a device IOTLB.
      *
@@ -666,6 +683,20 @@ void pci_device_unset_iommu_device(PCIDevice *dev);
  */
 uint64_t pci_device_get_viommu_flags(PCIDevice *dev);
 
+/**
+ * pci_device_get_host_iommu_quirks: get host IOMMU quirks.
+ *
+ * Returns: bitmap with each bit representing a host IOMMU quirk defined in
+ * enum host_iommu_quirks. Or 0 if vIOMMU doesn't convert any.
+ *
+ * @dev: PCI device pointer.
+ * @type: IOMMU hardware info type
+ * @caps: IOMMU @type specific hardware information data
+ * @size: size of @caps
+ */
+uint64_t pci_device_get_host_iommu_quirks(PCIDevice *dev, uint32_t type,
+                                          void *caps, uint32_t size);
+
 /**
  * pci_iommu_get_iotlb_info: get properties required to initialize a
  * device IOTLB.
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 8b62044a8e..520ec19982 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -3032,6 +3032,18 @@ uint64_t pci_device_get_viommu_flags(PCIDevice *dev)
     return 0;
 }
 
+uint64_t pci_device_get_host_iommu_quirks(PCIDevice *dev, uint32_t type,
+                                          void *caps, uint32_t size)
+{
+    PCIBus *iommu_bus;
+
+    pci_device_get_iommu_bus_devfn(dev, &iommu_bus, NULL, NULL);
+    if (iommu_bus && iommu_bus->iommu_ops->get_host_iommu_quirks) {
+        return iommu_bus->iommu_ops->get_host_iommu_quirks(type, caps, size);
+    }
+    return 0;
+}
+
 int pci_pri_request_page(PCIDevice *dev, uint32_t pasid, bool priv_req,
                          bool exec_req, hwaddr addr, bool lpig,
                          uint16_t prgi, bool is_read, bool is_write)
-- 
2.47.1