[PATCH v4 20/27] hw/arm/smmuv3: Add accel property for SMMUv3 device

Shameer Kolothum posted 27 patches 1 month, 2 weeks ago
There is a newer version of this series
[PATCH v4 20/27] hw/arm/smmuv3: Add accel property for SMMUv3 device
Posted by Shameer Kolothum 1 month, 2 weeks ago
Introduce an “accel” property to enable accelerator mode.

Live migration is currently unsupported when accelerator mode is enabled,
so a migration blocker is added.

Because this mode relies on IORT RMR for MSI support, accelerator mode is
not supported for device tree boot.

Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
---
 hw/arm/smmuv3.c         | 28 ++++++++++++++++++++++++++++
 hw/arm/virt.c           | 19 ++++++++++++-------
 include/hw/arm/smmuv3.h |  1 +
 3 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/hw/arm/smmuv3.c b/hw/arm/smmuv3.c
index 94b2bbc374..a0f704fc35 100644
--- a/hw/arm/smmuv3.c
+++ b/hw/arm/smmuv3.c
@@ -20,6 +20,7 @@
 #include "qemu/bitops.h"
 #include "hw/irq.h"
 #include "hw/sysbus.h"
+#include "migration/blocker.h"
 #include "migration/vmstate.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-core.h"
@@ -1916,6 +1917,17 @@ static void smmu_reset_exit(Object *obj, ResetType type)
     smmuv3_accel_attach_bypass_hwpt(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
+    return true;
+}
+
 static void smmu_realize(DeviceState *d, Error **errp)
 {
     SMMUState *sys = ARM_SMMU(d);
@@ -1924,8 +1936,17 @@ 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 "
+                   "accelerator mode enabled");
+        if (migrate_add_blocker(&s->migration_blocker, errp) < 0) {
+            return;
+        }
     }
 
     c->parent_realize(d, &local_err);
@@ -2025,6 +2046,7 @@ static const Property smmuv3_properties[] = {
      * Defaults to stage 1
      */
     DEFINE_PROP_STRING("stage", SMMUv3State, stage),
+    DEFINE_PROP_BOOL("accel", SMMUv3State, accel, false),
 };
 
 static void smmuv3_instance_init(Object *obj)
@@ -2046,6 +2068,12 @@ 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.c b/hw/arm/virt.c
index 6467d7cfc8..6b789fd7b5 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1474,8 +1474,8 @@ 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);
@@ -1483,10 +1483,15 @@ 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];
@@ -3086,7 +3091,7 @@ static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
                 }
             }
 
-            create_smmuv3_dev_dtb(vms, dev, bus);
+            create_smmuv3_dev_dtb(vms, dev, bus, errp);
             if (object_property_get_bool(OBJECT(dev), "accel", &error_abort) &&
                                          !vms->pci_preserve_config) {
                 vms->pci_preserve_config = true;
diff --git a/include/hw/arm/smmuv3.h b/include/hw/arm/smmuv3.h
index 5f3e9089a7..874cbaaf32 100644
--- a/include/hw/arm/smmuv3.h
+++ b/include/hw/arm/smmuv3.h
@@ -67,6 +67,7 @@ struct SMMUv3State {
     /* SMMU has HW accelerator support for nested S1 + s2 */
     bool accel;
     struct SMMUv3AccelState  *s_accel;
+    Error  *migration_blocker;
 };
 
 typedef enum {
-- 
2.43.0


Re: [PATCH v4 20/27] hw/arm/smmuv3: Add accel property for SMMUv3 device
Posted by Nicolin Chen 4 weeks, 1 day ago
On Mon, Sep 29, 2025 at 02:36:36PM +0100, Shameer Kolothum wrote:
> Introduce an “accel” property to enable accelerator mode.

Looks better with ASCII quotation marks: "accel".

> Live migration is currently unsupported when accelerator mode is enabled,
> so a migration blocker is added.
> 
> Because this mode relies on IORT RMR for MSI support, accelerator mode is
> not supported for device tree boot.
> 
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>

Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>

> @@ -67,6 +67,7 @@ struct SMMUv3State {
>      /* SMMU has HW accelerator support for nested S1 + s2 */
>      bool accel;
>      struct SMMUv3AccelState  *s_accel;
> +    Error  *migration_blocker;

No need of double space.

Re: [PATCH v4 20/27] hw/arm/smmuv3: Add accel property for SMMUv3 device
Posted by Eric Auger 2 weeks, 4 days ago

On 10/16/25 11:48 PM, Nicolin Chen wrote:
> On Mon, Sep 29, 2025 at 02:36:36PM +0100, Shameer Kolothum wrote:
>> Introduce an “accel” property to enable accelerator mode.
> Looks better with ASCII quotation marks: "accel".
>
>> Live migration is currently unsupported when accelerator mode is enabled,
>> so a migration blocker is added.
>>
>> Because this mode relies on IORT RMR for MSI support, accelerator mode is
>> not supported for device tree boot.
>>
>> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
> Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
>
>> @@ -67,6 +67,7 @@ struct SMMUv3State {
>>      /* SMMU has HW accelerator support for nested S1 + s2 */
>>      bool accel;
>>      struct SMMUv3AccelState  *s_accel;
>> +    Error  *migration_blocker;
> No need of double space.
>
With Nicolin's comments:

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

Eric