hw/xen: Add xenstore wire implementation and implementation stubs

This implements the basic wire protocol for the XenStore commands, punting
all the actual implementation to xs_impl_* functions which all just return
errors for now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/hw/i386/kvm/xenstore_impl.h b/hw/i386/kvm/xenstore_impl.h
new file mode 100644
index 0000000000..beb7b29ab8
--- /dev/null
+++ b/hw/i386/kvm/xenstore_impl.h
@@ -0,0 +1,58 @@
+/*
+ * QEMU Xen emulation: The actual implementation of XenStore
+ *
+ * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Authors: David Woodhouse <dwmw2@infradead.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_XENSTORE_IMPL_H
+#define QEMU_XENSTORE_IMPL_H
+
+typedef uint32_t xs_transaction_t;
+
+#define XBT_NULL 0
+
+typedef struct XenstoreImplState XenstoreImplState;
+
+XenstoreImplState *xs_impl_create(void);
+
+/*
+ * These functions return *positive* error numbers. This is a little
+ * unconventional but it helps to keep us honest because there is
+ * also a very limited set of error numbers that they are permitted
+ * to return (those in xsd_errors).
+ */
+
+int xs_impl_read(XenstoreImplState *s, unsigned int dom_id,
+                 xs_transaction_t tx_id, const char *path, GByteArray *data);
+int xs_impl_write(XenstoreImplState *s, unsigned int dom_id,
+                  xs_transaction_t tx_id, const char *path, GByteArray *data);
+int xs_impl_directory(XenstoreImplState *s, unsigned int dom_id,
+                      xs_transaction_t tx_id, const char *path,
+                      uint64_t *gencnt, GList **items);
+int xs_impl_transaction_start(XenstoreImplState *s, unsigned int dom_id,
+                              xs_transaction_t *tx_id);
+int xs_impl_transaction_end(XenstoreImplState *s, unsigned int dom_id,
+                            xs_transaction_t tx_id, bool commit);
+int xs_impl_rm(XenstoreImplState *s, unsigned int dom_id,
+               xs_transaction_t tx_id, const char *path);
+int xs_impl_get_perms(XenstoreImplState *s, unsigned int dom_id,
+                      xs_transaction_t tx_id, const char *path, GList **perms);
+int xs_impl_set_perms(XenstoreImplState *s, unsigned int dom_id,
+                      xs_transaction_t tx_id, const char *path, GList *perms);
+
+/* This differs from xs_watch_fn because it has the token */
+typedef void(xs_impl_watch_fn)(void *opaque, const char *path,
+                               const char *token);
+int xs_impl_watch(XenstoreImplState *s, unsigned int dom_id, const char *path,
+                  const char *token, xs_impl_watch_fn fn, void *opaque);
+int xs_impl_unwatch(XenstoreImplState *s, unsigned int dom_id,
+                    const char *path, const char *token, xs_impl_watch_fn fn,
+                    void *opaque);
+int xs_impl_reset_watches(XenstoreImplState *s, unsigned int dom_id);
+
+#endif /* QEMU_XENSTORE_IMPL_H */