virtio-net: make VirtIOFeature usable for other virtio devices

In order to use VirtIOFeature also in other virtio devices, we move
its declaration and the endof() macro (renamed in virtio_endof())
in virtio.h.
We add virtio_feature_get_config_size() function to iterate the array
of VirtIOFeature and to return the config size depending on the
features enabled. (as virtio_net_set_config_size() did)

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20190221103314.58500-5-sgarzare@redhat.com
Message-Id: <20190221103314.58500-5-sgarzare@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 9c1fa07d6d..ce9516236a 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -37,6 +37,21 @@ static inline hwaddr vring_align(hwaddr addr,
     return QEMU_ALIGN_UP(addr, align);
 }
 
+/*
+ * Calculate the number of bytes up to and including the given 'field' of
+ * 'container'.
+ */
+#define virtio_endof(container, field) \
+    (offsetof(container, field) + sizeof_field(container, field))
+
+typedef struct VirtIOFeature {
+    uint64_t flags;
+    size_t end;
+} VirtIOFeature;
+
+size_t virtio_feature_get_config_size(VirtIOFeature *features,
+                                      uint64_t host_features);
+
 typedef struct VirtQueue VirtQueue;
 
 #define VIRTQUEUE_MAX_SIZE 1024