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, 185 insertions, 0 deletions

diff --git a/migration/qemu-file.h b/migration/qemu-file.h
new file mode 100644
index 000000000..3f36d4dc8
--- /dev/null
+++ b/migration/qemu-file.h
@@ -0,0 +1,185 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MIGRATION_QEMU_FILE_H
+#define MIGRATION_QEMU_FILE_H
+
+#include <zlib.h>
+#include "exec/cpu-common.h"
+#include "io/channel.h"
+
+/* Read a chunk of data from a file at the given position.  The pos argument
+ * can be ignored if the file is only be used for streaming.  The number of
+ * bytes actually read should be returned.
+ */
+typedef ssize_t (QEMUFileGetBufferFunc)(void *opaque, uint8_t *buf,
+                                        int64_t pos, size_t size,
+                                        Error **errp);
+
+/* Close a file
+ *
+ * Return negative error number on error, 0 or positive value on success.
+ *
+ * The meaning of return value on success depends on the specific back-end being
+ * used.
+ */
+typedef int (QEMUFileCloseFunc)(void *opaque, Error **errp);
+
+/* Called to return the OS file descriptor associated to the QEMUFile.
+ */
+typedef int (QEMUFileGetFD)(void *opaque);
+
+/* Called to change the blocking mode of the file
+ */
+typedef int (QEMUFileSetBlocking)(void *opaque, bool enabled, Error **errp);
+
+/*
+ * This function writes an iovec to file. The handler must write all
+ * of the data or return a negative errno value.
+ */
+typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
+                                           int iovcnt, int64_t pos,
+                                           Error **errp);
+
+/*
+ * This function provides hooks around different
+ * stages of RAM migration.
+ * 'opaque' is the backend specific data in QEMUFile
+ * 'data' is call specific data associated with the 'flags' value
+ */
+typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags,
+                              void *data);
+
+/*
+ * Constants used by ram_control_* hooks
+ */
+#define RAM_CONTROL_SETUP     0
+#define RAM_CONTROL_ROUND     1
+#define RAM_CONTROL_HOOK      2
+#define RAM_CONTROL_FINISH    3
+#define RAM_CONTROL_BLOCK_REG 4
+
+/*
+ * This function allows override of where the RAM page
+ * is saved (such as RDMA, for example.)
+ */
+typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
+                               ram_addr_t block_offset,
+                               ram_addr_t offset,
+                               size_t size,
+                               uint64_t *bytes_sent);
+
+/*
+ * Return a QEMUFile for comms in the opposite direction
+ */
+typedef QEMUFile *(QEMURetPathFunc)(void *opaque);
+
+/*
+ * Stop any read or write (depending on flags) on the underlying
+ * transport on the QEMUFile.
+ * Existing blocking reads/writes must be woken
+ * Returns 0 on success, -err on error
+ */
+typedef int (QEMUFileShutdownFunc)(void *opaque, bool rd, bool wr,
+                                   Error **errp);
+
+typedef struct QEMUFileOps {
+    QEMUFileGetBufferFunc *get_buffer;
+    QEMUFileCloseFunc *close;
+    QEMUFileSetBlocking *set_blocking;
+    QEMUFileWritevBufferFunc *writev_buffer;
+    QEMURetPathFunc *get_return_path;
+    QEMUFileShutdownFunc *shut_down;
+} QEMUFileOps;
+
+typedef struct QEMUFileHooks {
+    QEMURamHookFunc *before_ram_iterate;
+    QEMURamHookFunc *after_ram_iterate;
+    QEMURamHookFunc *hook_ram_load;
+    QEMURamSaveFunc *save_page;
+} QEMUFileHooks;
+
+QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops, bool has_ioc);
+void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
+int qemu_get_fd(QEMUFile *f);
+int qemu_fclose(QEMUFile *f);
+int64_t qemu_ftell(QEMUFile *f);
+int64_t qemu_ftell_fast(QEMUFile *f);
+/*
+ * put_buffer without copying the buffer.
+ * The buffer should be available till it is sent asynchronously.
+ */
+void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
+                           bool may_free);
+bool qemu_file_mode_is_not_valid(const char *mode);
+bool qemu_file_is_writable(QEMUFile *f);
+
+#include "migration/qemu-file-types.h"
+
+size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset);
+size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size);
+ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
+                                  const uint8_t *p, size_t size);
+int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src);
+
+/*
+ * Note that you can only peek continuous bytes from where the current pointer
+ * is; you aren't guaranteed to be able to peak to +n bytes unless you've
+ * previously peeked +n-1.
+ */
+int qemu_peek_byte(QEMUFile *f, int offset);
+void qemu_file_skip(QEMUFile *f, int size);
+void qemu_update_position(QEMUFile *f, size_t size);
+void qemu_file_reset_rate_limit(QEMUFile *f);
+void qemu_file_update_transfer(QEMUFile *f, int64_t len);
+void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
+int64_t qemu_file_get_rate_limit(QEMUFile *f);
+int qemu_file_get_error_obj(QEMUFile *f, Error **errp);
+void qemu_file_set_error_obj(QEMUFile *f, int ret, Error *err);
+void qemu_file_set_error(QEMUFile *f, int ret);
+int qemu_file_shutdown(QEMUFile *f);
+QEMUFile *qemu_file_get_return_path(QEMUFile *f);
+void qemu_fflush(QEMUFile *f);
+void qemu_file_set_blocking(QEMUFile *f, bool block);
+
+void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
+void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
+void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
+
+/* Whenever this is found in the data stream, the flags
+ * will be passed to ram_control_load_hook in the incoming-migration
+ * side. This lets before_ram_iterate/after_ram_iterate add
+ * transport-specific sections to the RAM migration data.
+ */
+#define RAM_SAVE_FLAG_HOOK     0x80
+
+#define RAM_SAVE_CONTROL_NOT_SUPP -1000
+#define RAM_SAVE_CONTROL_DELAYED  -2000
+
+size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
+                             ram_addr_t offset, size_t size,
+                             uint64_t *bytes_sent);
+QIOChannel *qemu_file_get_ioc(QEMUFile *file);
+
+#endif