Implement get_viommu_flags() callback and expose a request for nesting
parent HWPT for now.

VFIO uses it to create nesting parent HWPT which is further used to create
nested HWPT in vIOMMU. All these will be implemented in following patches.

Suggested-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
---
 hw/i386/intel_iommu.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index ab8037a666..43f3a49769 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -24,6 +24,7 @@
 #include "qemu/main-loop.h"
 #include "qapi/error.h"
 #include "hw/sysbus.h"
+#include "hw/iommu.h"
 #include "intel_iommu_internal.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bus.h"
@@ -4696,6 +4697,16 @@ static void vtd_address_space_unmap_in_migration(VTDAddressSpace *as,
     }
 }
 
+static uint64_t vtd_get_viommu_flags(void *opaque)
+{
+    IntelIOMMUState *s = opaque;
+    uint64_t flags;
+
+    flags = s->fsts ? VIOMMU_FLAG_WANT_NESTING_PARENT : 0;
+
+    return flags;
+}
+
 /* Unmap the whole range in the notifier's scope. */
 static void vtd_address_space_unmap(VTDAddressSpace *as, IOMMUNotifier *n)
 {
@@ -5354,6 +5365,7 @@ static PCIIOMMUOps vtd_iommu_ops = {
     .pri_register_notifier = vtd_pri_register_notifier,
     .pri_unregister_notifier = vtd_pri_unregister_notifier,
     .pri_request_page = vtd_pri_request_page,
+    .get_viommu_flags = vtd_get_viommu_flags,
 };
 
 static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
-- 
2.47.1