[Qemu-devel] [PATCH] virtio: set virtio-mmio transport features for various backends

[Mario Smarduch]

virtio:  set virtio-mmio transport features for various backends

Hi Peter, i.e others -

This is a second attempt at setting transport backend features, for
back-ends that are instantiated separately from transport and dynamically
plugged in. virtio-mmio transport is addressed by this patch for virtio-net
and virtio-blk back-ends.

This patch declares features for all back-ends in the transport file,
and based on the type of back-end applies the back-end features. A hook
is added in VirtioBusClass that each transport can override
to apply specific features for a back-end. The hook is called with the
back-end device when it's plugged in.

Thanks,
 Mario.

Signed-off-by: Mario Smarduch <m.smard...@samsung.com>
---
 hw/virtio/virtio-bus.c         |    5 +++++
 hw/virtio/virtio-mmio.c        |   46 ++++++++++++++++++++++++++++++++++++++++
 include/hw/virtio/virtio-bus.h |    4 ++++
 3 files changed, 55 insertions(+)

diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
index eb77019..5eb9ba1 100644
--- a/hw/virtio/virtio-bus.c
+++ b/hw/virtio/virtio-bus.c
@@ -44,8 +44,13 @@ int virtio_bus_device_plugged(VirtIODevice *vdev)
     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
     VirtioBusState *bus = VIRTIO_BUS(qbus);
     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
+    DeviceState *proxy = DEVICE(qbus->parent);
     DPRINTF("%s: plug device.\n", qbus->name);

+    if (klass->set_transport_features != NULL) {
+        klass->set_transport_features(proxy);
+    }
+
     if (klass->device_plugged != NULL) {
         klass->device_plugged(qbus->parent);
     }
diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
index 8829eb0..f4e67a2 100644
--- a/hw/virtio/virtio-mmio.c
+++ b/hw/virtio/virtio-mmio.c
@@ -23,6 +23,8 @@
 #include "hw/virtio/virtio.h"
 #include "qemu/host-utils.h"
 #include "hw/virtio/virtio-bus.h"
+#include "hw/virtio/virtio-net.h"
+#include "hw/virtio/virtio-blk.h"

 /* #define DEBUG_VIRTIO_MMIO */

@@ -89,6 +91,49 @@ typedef struct {
     VirtioBusState bus;
 } VirtIOMMIOProxy;

+/* supported features for virtio-net backend */
+static Property virtio_net_transport_properties[] = {
+    DEFINE_VIRTIO_NET_FEATURES(VirtIOMMIOProxy, host_features),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+/* supported features for virtio-blk backend */
+static Property virtio_blk_transport_properties[] = {
+    DEFINE_VIRTIO_BLK_FEATURES(VirtIOMMIOProxy, host_features),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static struct {
+    const char *backend_name;
+    const Property *props;
+} mmio_transport_backends[] = {
+    { TYPE_VIRTIO_NET, virtio_net_transport_properties },
+    { TYPE_VIRTIO_BLK, virtio_blk_transport_properties },
+    { NULL, NULL },
+};
+
+
+static void virtio_mmio_set_transport_features(DeviceState *d)
+{
+    VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
+    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
+    int i;
+
+    for (i = 0; mmio_transport_backends[i].backend_name != NULL; i++) {
+        if (object_dynamic_cast(OBJECT(vdev),
+                                 mmio_transport_backends[i].backend_name)) {
+            const Property *props =  mmio_transport_backends[i].props;
+            for (; props->qtype == QTYPE_QBOOL && props->qtype != QTYPE_NONE;
+                   props++) {
+                if (props->defval == true) {
+                    proxy->host_features |= (1 << props->bitnr);
+                } else {
+                    proxy->host_features &= ~(1 << props->bitnr);
+                }
+            }
+        }
+    }
+}
 static void virtio_mmio_bus_new(VirtioBusState *bus, size_t bus_size,
                                 VirtIOMMIOProxy *dev);

@@ -408,6 +453,7 @@ static void virtio_mmio_bus_class_init(ObjectClass *klass, 
void *data)
     k->load_config = virtio_mmio_load_config;
     k->get_features = virtio_mmio_get_features;
     k->device_plugged = virtio_mmio_device_plugged;
+    k->set_transport_features = virtio_mmio_set_transport_features;
     k->has_variable_vring_alignment = true;
     bus_class->max_dev = 1;
 }
diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
index 0756545..3136fc6 100644
--- a/include/hw/virtio/virtio-bus.h
+++ b/include/hw/virtio/virtio-bus.h
@@ -62,6 +62,10 @@ typedef struct VirtioBusClass {
      * This is called by virtio-bus just before the device is unplugged.
      */
     void (*device_unplugged)(DeviceState *d);
+    /* Call before plugging a backend into transport to set features supported
+     * by the backend.
+     */
+    void (*set_transport_features)(DeviceState *d);
     /*
      * Does the transport have variable vring alignment?
      * (ie can it ever call virtio_queue_set_align()?)
-- 
1.7.9.5