hw/arm/virt: Default to two-stage SMMU from virt-9.2

Now that our SMMU model supports enabling both stages of translation
at once, we can enable this in the virt board.  This is no change in
behaviour for guests, because if they simply ignore stage 2 and never
configure it then it has no effect.  For the usual backwards
compatibility reasons we enable this only for machine types starting
with 9.2.

(Note that the SMMU is disabled by default on the virt board and is
only created if the user passes the 'iommu=smmuv3' machine option.)

Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Eric Auger <[email protected]>
Reviewed-by: Daniel P. Berrangé <[email protected]>
Message-id: [email protected]

hw/arm/virt.c

@@ -1408,6 +1408,7 @@ static void create_pcie_irq_map(const MachineState *ms,
 static void create_smmu(const VirtMachineState *vms,
                         PCIBus *bus)
 {
+    VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
     char *node;
     const char compat[] = "arm,smmu-v3";
     int irq =  vms->irqmap[VIRT_SMMU];
@@ -1424,6 +1425,9 @@ static void create_smmu(const VirtMachineState *vms,
 
     dev = qdev_new(TYPE_ARM_SMMUV3);
 
+    if (!vmc->no_nested_smmu) {
+        object_property_set_str(OBJECT(dev), "stage", "nested", &error_fatal);
+    }
     object_property_set_link(OBJECT(dev), "primary-bus", OBJECT(bus),
                              &error_abort);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
@@ -3308,8 +3312,12 @@ DEFINE_VIRT_MACHINE_AS_LATEST(9, 2)
 
 static void virt_machine_9_1_options(MachineClass *mc)
 {
+    VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
+
     virt_machine_9_2_options(mc);
     compat_props_add(mc->compat_props, hw_compat_9_1, hw_compat_9_1_len);
+    /* 9.1 and earlier have only a stage-1 SMMU, not a nested s1+2 one */
+    vmc->no_nested_smmu = true;
 }
 DEFINE_VIRT_MACHINE(9, 1)
 

include/hw/arm/virt.h

@@ -134,6 +134,7 @@ struct VirtMachineClass {
     bool no_cpu_topology;
     bool no_tcg_lpa2;
     bool no_ns_el2_virt_timer_irq;
+    bool no_nested_smmu;
 };
 
 struct VirtMachineState {