4 files changed, 58 insertions, 0 deletions

diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index bff9152..98dd06a 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -877,6 +877,52 @@ PropertyInfo qdev_prop_pci_devfn = {
     .max   = 0xFFFFFFFFULL,
 };
 
+/* --- blocksize --- */
+
+static void set_blocksize(Object *obj, Visitor *v, void *opaque,
+                          const char *name, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
+    int16_t *ptr = qdev_get_prop_ptr(dev, prop);
+    Error *local_err = NULL;
+    int64_t value;
+
+    if (dev->state != DEV_STATE_CREATED) {
+        error_set(errp, QERR_PERMISSION_DENIED);
+        return;
+    }
+
+    visit_type_int(v, &value, name, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+    if (value < prop->info->min || value > prop->info->max) {
+        error_set(errp, QERR_PROPERTY_VALUE_OUT_OF_RANGE,
+                  dev->id?:"", name, value, prop->info->min,
+                  prop->info->max);
+        return;
+    }
+
+    /* We rely on power-of-2 blocksizes for bitmasks */
+    if ((value & (value - 1)) != 0) {
+        error_set(errp, QERR_PROPERTY_VALUE_NOT_POWER_OF_2,
+                  dev->id?:"", name, value);
+        return;
+    }
+
+    *ptr = value;
+}
+
+PropertyInfo qdev_prop_blocksize = {
+    .name  = "blocksize",
+    .get   = get_int16,
+    .set   = set_blocksize,
+    .min   = 512,
+    .max   = 65024,
+};
+
 /* --- public helpers --- */
 
 static Property *qdev_prop_walk(Property *props, const char *name)
diff --git a/hw/qdev.h b/hw/qdev.h
index a8df42f..1c10960 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -223,6 +223,7 @@ extern PropertyInfo qdev_prop_drive;
 extern PropertyInfo qdev_prop_netdev;
 extern PropertyInfo qdev_prop_vlan;
 extern PropertyInfo qdev_prop_pci_devfn;
+extern PropertyInfo qdev_prop_blocksize;
 
 #define DEFINE_PROP(_name, _state, _field, _prop, _type) { \
         .name      = (_name),                                    \
@@ -284,6 +285,8 @@ extern PropertyInfo qdev_prop_pci_devfn;
 #define DEFINE_PROP_LOSTTICKPOLICY(_n, _s, _f, _d) \
     DEFINE_PROP_DEFAULT(_n, _s, _f, _d, qdev_prop_losttickpolicy, \
                         LostTickPolicy)
+#define DEFINE_PROP_BLOCKSIZE(_n, _s, _f, _d) \
+    DEFINE_PROP_DEFAULT(_n, _s, _f, _d, qdev_prop_blocksize, uint16_t)
 
 #define DEFINE_PROP_END_OF_LIST()               \
     {}
diff --git a/qerror.c b/qerror.c
index 1f565fc..96fbe71 100644
--- a/qerror.c
+++ b/qerror.c
@@ -241,6 +241,11 @@ static const QErrorStringTable qerror_table[] = {
         .desc      = "Property '%(device).%(property)' can't find value '%(value)'",
     },
     {
+        .error_fmt = QERR_PROPERTY_VALUE_NOT_POWER_OF_2,
+        .desc      = "Property '%(device).%(property)' doesn't take "
+                     "value '%(value)', it's not a power of 2",
+    },
+    {
         .error_fmt = QERR_PROPERTY_VALUE_OUT_OF_RANGE,
         .desc      = "Property '%(device).%(property)' doesn't take "
                      "value %(value) (minimum: %(min), maximum: %(max))",
diff --git a/qerror.h b/qerror.h
index e16f9c2..5c23c1f 100644
--- a/qerror.h
+++ b/qerror.h
@@ -202,6 +202,10 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_PROPERTY_VALUE_NOT_FOUND \
     "{ 'class': 'PropertyValueNotFound', 'data': { 'device': %s, 'property': %s, 'value': %s } }"
 
+#define QERR_PROPERTY_VALUE_NOT_POWER_OF_2 \
+    "{ 'class': 'PropertyValueNotPowerOf2', 'data': { " \
+    "'device': %s, 'property': %s, 'value': %"PRId64" } }"
+
 #define QERR_PROPERTY_VALUE_OUT_OF_RANGE \
     "{ 'class': 'PropertyValueOutOfRange', 'data': { 'device': %s, 'property': %s, 'value': %"PRId64", 'min': %"PRId64", 'max': %"PRId64" } }"