Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 99 insertions, 0 deletions

diff --git a/hw/misc/unimp.c b/hw/misc/unimp.c
new file mode 100644
index 000000000..6cfc5727f
--- /dev/null
+++ b/hw/misc/unimp.c
@@ -0,0 +1,99 @@
+/* "Unimplemented" device
+ *
+ * This is a dummy device which accepts and logs all accesses.
+ * It's useful for stubbing out regions of an SoC or board
+ * map which correspond to devices that have not yet been
+ * implemented. This is often sufficient to placate initial
+ * guest device driver probing such that the system will
+ * come up.
+ *
+ * Copyright Linaro Limited, 2017
+ * Written by Peter Maydell
+ */
+
+#include "qemu/osdep.h"
+#include "hw/sysbus.h"
+#include "hw/misc/unimp.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+
+static uint64_t unimp_read(void *opaque, hwaddr offset, unsigned size)
+{
+    UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
+
+    qemu_log_mask(LOG_UNIMP, "%s: unimplemented device read  "
+                  "(size %d, offset 0x%0*" HWADDR_PRIx ")\n",
+                  s->name, size, s->offset_fmt_width, offset);
+    return 0;
+}
+
+static void unimp_write(void *opaque, hwaddr offset,
+                        uint64_t value, unsigned size)
+{
+    UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
+
+    qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
+                  "(size %d, offset 0x%0*" HWADDR_PRIx
+                  ", value 0x%0*" PRIx64 ")\n",
+                  s->name, size, s->offset_fmt_width, offset, size << 1, value);
+}
+
+static const MemoryRegionOps unimp_ops = {
+    .read = unimp_read,
+    .write = unimp_write,
+    .impl.min_access_size = 1,
+    .impl.max_access_size = 8,
+    .valid.min_access_size = 1,
+    .valid.max_access_size = 8,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void unimp_realize(DeviceState *dev, Error **errp)
+{
+    UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(dev);
+
+    if (s->size == 0) {
+        error_setg(errp, "property 'size' not specified or zero");
+        return;
+    }
+
+    if (s->name == NULL) {
+        error_setg(errp, "property 'name' not specified");
+        return;
+    }
+
+    s->offset_fmt_width = DIV_ROUND_UP(64 - clz64(s->size - 1), 4);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s,
+                          s->name, s->size);
+    sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
+}
+
+static Property unimp_properties[] = {
+    DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0),
+    DEFINE_PROP_STRING("name", UnimplementedDeviceState, name),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void unimp_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = unimp_realize;
+    device_class_set_props(dc, unimp_properties);
+}
+
+static const TypeInfo unimp_info = {
+    .name = TYPE_UNIMPLEMENTED_DEVICE,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(UnimplementedDeviceState),
+    .class_init = unimp_class_init,
+};
+
+static void unimp_register_types(void)
+{
+    type_register_static(&unimp_info);
+}
+
+type_init(unimp_register_types)