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, 81 insertions, 0 deletions

diff --git a/util/aio-posix.h b/util/aio-posix.h
new file mode 100644
index 000000000..c80c04506
--- /dev/null
+++ b/util/aio-posix.h
@@ -0,0 +1,81 @@
+/*
+ * AioContext POSIX event loop implementation internal APIs
+ *
+ * Copyright IBM, Corp. 2008
+ * Copyright Red Hat, Inc. 2020
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#ifndef AIO_POSIX_H
+#define AIO_POSIX_H
+
+#include "block/aio.h"
+
+struct AioHandler {
+    GPollFD pfd;
+    IOHandler *io_read;
+    IOHandler *io_write;
+    AioPollFn *io_poll;
+    IOHandler *io_poll_begin;
+    IOHandler *io_poll_end;
+    void *opaque;
+    QLIST_ENTRY(AioHandler) node;
+    QLIST_ENTRY(AioHandler) node_ready; /* only used during aio_poll() */
+    QLIST_ENTRY(AioHandler) node_deleted;
+    QLIST_ENTRY(AioHandler) node_poll;
+#ifdef CONFIG_LINUX_IO_URING
+    QSLIST_ENTRY(AioHandler) node_submitted;
+    unsigned flags; /* see fdmon-io_uring.c */
+#endif
+    int64_t poll_idle_timeout; /* when to stop userspace polling */
+    bool is_external;
+};
+
+/* Add a handler to a ready list */
+void aio_add_ready_handler(AioHandlerList *ready_list, AioHandler *node,
+                           int revents);
+
+extern const FDMonOps fdmon_poll_ops;
+
+#ifdef CONFIG_EPOLL_CREATE1
+bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd);
+void fdmon_epoll_setup(AioContext *ctx);
+void fdmon_epoll_disable(AioContext *ctx);
+#else
+static inline bool fdmon_epoll_try_upgrade(AioContext *ctx, unsigned npfd)
+{
+    return false;
+}
+
+static inline void fdmon_epoll_setup(AioContext *ctx)
+{
+}
+
+static inline void fdmon_epoll_disable(AioContext *ctx)
+{
+}
+#endif /* !CONFIG_EPOLL_CREATE1 */
+
+#ifdef CONFIG_LINUX_IO_URING
+bool fdmon_io_uring_setup(AioContext *ctx);
+void fdmon_io_uring_destroy(AioContext *ctx);
+#else
+static inline bool fdmon_io_uring_setup(AioContext *ctx)
+{
+    return false;
+}
+
+static inline void fdmon_io_uring_destroy(AioContext *ctx)
+{
+}
+#endif /* !CONFIG_LINUX_IO_URING */
+
+#endif /* AIO_POSIX_H */