Add an "accel" property to enable SMMUv3 accelerator mode.

Accelerator mode relies on IORT RMR entries for MSI support and is
therefore not supported when booting with a device tree.

In this mode, the host SMMUv3 operates in nested translation
(Stage-1 + Stage-2), with the guest owning the Stage-1 page tables.
Expose only Stage-1 to the guest to ensure it uses the correct page
table format

Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
---
 hw/arm/smmuv3.c          | 32 ++++++++++++++++++++++++++++++++
 hw/arm/virt-acpi-build.c |  4 +---
 hw/arm/virt.c            | 23 ++++++++++++++---------
 3 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 2be056d792..8ca1d4ad35 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -1916,6 +1916,29 @@ static void smmu_reset_exit(Object *obj, ResetType type)
     smmuv3_accel_reset(s);
 }
 
+static bool smmu_validate_property(SMMUv3State *s, Error **errp)
+{
+#ifndef CONFIG_ARM_SMMUV3_ACCEL
+    if (s->accel) {
+        error_setg(errp, "accel=on support not compiled in");
+        return false;
+    }
+#endif
+
+    if (!s->accel) {
+        return true;
+    }
+
+    /* If no stage specified, SMMUv3 defaults to stage 1 */
+    if (s->stage && strcmp(s->stage, "1")) {
+        error_setg(errp,
+                   "Only stage1 is supported for SMMUv3 with accel=on");
+        return false;
+    }
+
+    return true;
+}
+
 static void smmu_realize(DeviceState *d, Error **errp)
 {
     SMMUState *sys = ARM_SMMU(d);
@@ -1924,6 +1947,10 @@ static void smmu_realize(DeviceState *d, Error **errp)
     SysBusDevice *dev = SYS_BUS_DEVICE(d);
     Error *local_err = NULL;
 
+    if (!smmu_validate_property(s, errp)) {
+        return;
+    }
+
     if (s->accel) {
         smmuv3_accel_init(s);
         error_setg(&s->migration_blocker, "Migration not supported with SMMUv3 "
@@ -2029,6 +2056,7 @@ static const Property smmuv3_properties[] = {
      * Defaults to stage 1
      */
     DEFINE_PROP_STRING("stage", SMMUv3State, stage),
+    DEFINE_PROP_BOOL("accel", SMMUv3State, accel, false),
     /* GPA of MSI doorbell, for SMMUv3 accel use. */
     DEFINE_PROP_UINT64("msi-gpa", SMMUv3State, msi_gpa, 0),
 };
@@ -2052,6 +2080,10 @@ static void smmuv3_class_init(ObjectClass *klass, const void *data)
     device_class_set_props(dc, smmuv3_properties);
     dc->hotpluggable = false;
     dc->user_creatable = true;
+
+    object_class_property_set_description(klass, "accel",
+        "Enable SMMUv3 accelerator support. Allows host SMMUv3 to be "
+        "configured in nested mode for vfio-pci dev assignment");
 }
 
 static int smmuv3_notify_flag_changed(IOMMUMemoryRegion *iommu,
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 89abbf641b..bb408de43a 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -400,9 +400,7 @@ static int iort_smmuv3_devices(Object *obj, void *opaque)
     }
 
     bus = PCI_BUS(object_property_get_link(obj, "primary-bus", &error_abort));
-    if (object_property_find(obj, "accel")) {
-        sdev.accel = object_property_get_bool(obj, "accel", &error_abort);
-    }
+    sdev.accel = object_property_get_bool(obj, "accel", &error_abort);
     pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
     sbdev = SYS_BUS_DEVICE(obj);
     sdev.base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index d0321cea2d..c7de5fe185 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1491,8 +1491,8 @@ static void create_smmuv3_dt_bindings(const VirtMachineState *vms, hwaddr base,
     g_free(node);
 }
 
-static void create_smmuv3_dev_dtb(VirtMachineState *vms,
-                                  DeviceState *dev, PCIBus *bus)
+static void create_smmuv3_dev_dtb(VirtMachineState *vms, DeviceState *dev,
+                                  PCIBus *bus, Error **errp)
 {
     PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
     SysBusDevice *sbdev = SYS_BUS_DEVICE(dev);
@@ -1500,11 +1500,17 @@ static void create_smmuv3_dev_dtb(VirtMachineState *vms,
     hwaddr base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
     MachineState *ms = MACHINE(vms);
 
-    if (!(vms->bootinfo.firmware_loaded && virt_is_acpi_enabled(vms)) &&
-        strcmp("pcie.0", bus->qbus.name)) {
-        warn_report("SMMUv3 device only supported with pcie.0 for DT");
-        return;
+    if (!(vms->bootinfo.firmware_loaded && virt_is_acpi_enabled(vms))) {
+        if (object_property_get_bool(OBJECT(dev), "accel", &error_abort)) {
+            error_setg(errp, "SMMUv3 with accel=on not supported for DT");
+            return;
+        }
+        if (strcmp("pcie.0", bus->qbus.name)) {
+            warn_report("SMMUv3 device only supported with pcie.0 for DT");
+            return;
+        }
     }
+
     base += vms->memmap[VIRT_PLATFORM_BUS].base;
     irq += vms->irqmap[VIRT_PLATFORM_BUS];
 
@@ -3052,8 +3058,7 @@ static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
             /* The new SMMUv3 device is specific to the PCI bus */
             object_property_set_bool(OBJECT(dev), "smmu_per_bus", true, NULL);
         }
-        if (object_property_find(OBJECT(dev), "accel") &&
-            object_property_get_bool(OBJECT(dev), "accel", &error_abort)) {
+        if (object_property_get_bool(OBJECT(dev), "accel", &error_abort)) {
             hwaddr db_start;
 
             if (!kvm_enabled() || !kvm_irqchip_in_kernel()) {
@@ -3108,7 +3113,7 @@ static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
                 return;
             }
 
-            create_smmuv3_dev_dtb(vms, dev, bus);
+            create_smmuv3_dev_dtb(vms, dev, bus, errp);
         }
     }
 
-- 
2.43.0