xen: backend driver core (Gerd Hoffmann)

This patch adds infrastructure for xen backend drivers living in qemu,
so drivers don't need to implement common stuff on their own.  It's
mostly xenbus management stuff: some functions to access xentore,
setting up xenstore watches, callbacks on device discovery and state
changes, handle event channel, ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7220 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 86 insertions, 0 deletions

diff --git a/hw/xen_backend.h b/hw/xen_backend.h
new file mode 100644
index 0000000000..a1243f6b05
--- /dev/null
+++ b/hw/xen_backend.h
@@ -0,0 +1,86 @@
+#ifndef QEMU_HW_XEN_BACKEND_H
+#define QEMU_HW_XEN_BACKEND_H 1
+
+#include "xen_common.h"
+
+/* ------------------------------------------------------------- */
+
+#define XEN_BUFSIZE 1024
+
+struct XenDevice;
+
+/* driver uses grant tables  ->  open gntdev device (xendev->gnttabdev) */
+#define DEVOPS_FLAG_NEED_GNTDEV   1
+/* don't expect frontend doing correct state transitions (aka console quirk) */
+#define DEVOPS_FLAG_IGNORE_STATE  2
+
+struct XenDevOps {
+    size_t    size;
+    uint32_t  flags;
+    void      (*alloc)(struct XenDevice *xendev);
+    int       (*init)(struct XenDevice *xendev);
+    int       (*connect)(struct XenDevice *xendev);
+    void      (*event)(struct XenDevice *xendev);
+    void      (*disconnect)(struct XenDevice *xendev);
+    int       (*free)(struct XenDevice *xendev);
+    void      (*backend_changed)(struct XenDevice *xendev, const char *node);
+    void      (*frontend_changed)(struct XenDevice *xendev, const char *node);
+};
+
+struct XenDevice {
+    const char         *type;
+    int                dom;
+    int                dev;
+    char               name[64];
+    int                debug;
+
+    enum xenbus_state  be_state;
+    enum xenbus_state  fe_state;
+    int                online;
+    char               be[XEN_BUFSIZE];
+    char               *fe;
+    char               *protocol;
+    int                remote_port;
+    int                local_port;
+
+    int                evtchndev;
+    int                gnttabdev;
+
+    struct XenDevOps   *ops;
+    TAILQ_ENTRY(XenDevice) next;
+};
+
+/* ------------------------------------------------------------- */
+
+/* variables */
+extern int xen_xc;
+extern struct xs_handle *xenstore;
+
+/* xenstore helper functions */
+int xenstore_write_str(const char *base, const char *node, const char *val);
+int xenstore_write_int(const char *base, const char *node, int ival);
+char *xenstore_read_str(const char *base, const char *node);
+int xenstore_read_int(const char *base, const char *node, int *ival);
+
+int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val);
+int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival);
+char *xenstore_read_be_str(struct XenDevice *xendev, const char *node);
+int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival);
+char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node);
+int xenstore_read_fe_int(struct XenDevice *xendev, const char *node, int *ival);
+
+const char *xenbus_strstate(enum xenbus_state state);
+struct XenDevice *xen_be_find_xendev(const char *type, int dom, int dev);
+void xen_be_check_state(struct XenDevice *xendev);
+
+/* xen backend driver bits */
+int xen_be_init(void);
+int xen_be_register(const char *type, struct XenDevOps *ops);
+int xen_be_set_state(struct XenDevice *xendev, enum xenbus_state state);
+int xen_be_bind_evtchn(struct XenDevice *xendev);
+void xen_be_unbind_evtchn(struct XenDevice *xendev);
+int xen_be_send_notify(struct XenDevice *xendev);
+void xen_be_printf(struct XenDevice *xendev, int msg_level, const char *fmt, ...)
+    __attribute__ ((format(printf, 3, 4)));
+
+#endif /* QEMU_HW_XEN_BACKEND_H */