Currently the default input range can extend to 64 bits. On x86,
when the virtio-iommu protects vfio devices, the physical iommu
may support only 39 bits. Let's set the default to 39, as done
for the intel-iommu.

We use hw_compat_8_2 to handle the compatibility for machines
before 9.0 which used to have a virtio-iommu default input range
of 64 bits.

Of course if aw-bits is set from the command line, the default
is overriden.

Signed-off-by: Eric Auger <eric.auger@redhat.com>

---

v6 -> v7:
- use static pc_q35_compat_defaults
- remove spurious header addition
- s/32/UINT32_MAX in the qtest

v5 -> v6:
- split pc/arm settings

v3 -> v4:
- update the qos test to relax the check on the max input IOVA

v2 -> v3:
- collected Zhenzhong's R-b
- use &error_abort instead of NULL error handle
  on object_property_get_uint() call (Cédric)
- use VTD_HOST_AW_39BIT (Cédric)

v1 -> v2:
- set aw-bits to 48b on ARM
- use hw_compat_8_2 to handle the compat for older machines
  which used 64b as a default
---
 hw/core/machine.c               | 1 +
 hw/i386/pc_q35.c                | 9 +++++++++
 tests/qtest/virtio-iommu-test.c | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 6bd09d4592..4b89172d1c 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -35,6 +35,7 @@
 
 GlobalProperty hw_compat_8_2[] = {
     { TYPE_VIRTIO_IOMMU_PCI, "granule", "4k" },
+    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "64" },
 };
 const size_t hw_compat_8_2_len = G_N_ELEMENTS(hw_compat_8_2);
 
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 45a4102e75..1e7464d39a 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -45,6 +45,7 @@
 #include "hw/i386/pc.h"
 #include "hw/i386/amd_iommu.h"
 #include "hw/i386/intel_iommu.h"
+#include "hw/virtio/virtio-iommu.h"
 #include "hw/display/ramfb.h"
 #include "hw/ide/pci.h"
 #include "hw/ide/ahci-pci.h"
@@ -63,6 +64,12 @@
 /* ICH9 AHCI has 6 ports */
 #define MAX_SATA_PORTS     6
 
+static GlobalProperty pc_q35_compat_defaults[] = {
+    { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "39" },
+};
+static const size_t pc_q35_compat_defaults_len =
+    G_N_ELEMENTS(pc_q35_compat_defaults);
+
 struct ehci_companions {
     const char *name;
     int func;
@@ -356,6 +363,8 @@ static void pc_q35_machine_options(MachineClass *m)
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE);
     machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE);
+    compat_props_add(m->compat_props,
+                     pc_q35_compat_defaults, pc_q35_compat_defaults_len);
 }
 
 static void pc_q35_9_0_machine_options(MachineClass *m)
diff --git a/tests/qtest/virtio-iommu-test.c b/tests/qtest/virtio-iommu-test.c
index 068e7a9e6c..afb225971d 100644
--- a/tests/qtest/virtio-iommu-test.c
+++ b/tests/qtest/virtio-iommu-test.c
@@ -34,7 +34,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
     uint8_t bypass = qvirtio_config_readb(dev, 36);
 
     g_assert_cmpint(input_range_start, ==, 0);
-    g_assert_cmphex(input_range_end, ==, UINT64_MAX);
+    g_assert_cmphex(input_range_end, >=, UINT32_MAX);
     g_assert_cmpint(domain_range_start, ==, 0);
     g_assert_cmpint(domain_range_end, ==, UINT32_MAX);
     g_assert_cmpint(bypass, ==, 1);
-- 
2.41.0