libvhost-user: add glib source helper

This file implements a bridge from the vu_init API of libvhost-user to
GSource, so that libvhost-user can be used inside a GLib main loop.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

contrib/libvhost-user/Makefile.objs

@@ -1 +1 @@
-libvhost-user-obj-y = libvhost-user.o
+libvhost-user-obj-y += libvhost-user.o libvhost-user-glib.o

contrib/libvhost-user/libvhost-user-glib.c

@@ -0,0 +1,154 @@
+/*
+ * Vhost User library
+ *
+ * Copyright (c) 2016 Nutanix Inc. All rights reserved.
+ * Copyright (c) 2017 Red Hat, Inc.
+ *
+ * Authors:
+ *  Marc-André Lureau <mlureau@redhat.com>
+ *  Felipe Franciosi <felipe@nutanix.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later.  See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+#include "libvhost-user-glib.h"
+
+/* glib event loop integration for libvhost-user and misc callbacks */
+
+G_STATIC_ASSERT((int)G_IO_IN == (int)VU_WATCH_IN);
+G_STATIC_ASSERT((int)G_IO_OUT == (int)VU_WATCH_OUT);
+G_STATIC_ASSERT((int)G_IO_PRI == (int)VU_WATCH_PRI);
+G_STATIC_ASSERT((int)G_IO_ERR == (int)VU_WATCH_ERR);
+G_STATIC_ASSERT((int)G_IO_HUP == (int)VU_WATCH_HUP);
+
+typedef struct VugSrc {
+    GSource parent;
+    VuDev *dev;
+    GPollFD gfd;
+} VugSrc;
+
+static gboolean
+vug_src_prepare(GSource *gsrc, gint *timeout)
+{
+    g_assert(timeout);
+
+    *timeout = -1;
+    return FALSE;
+}
+
+static gboolean
+vug_src_check(GSource *gsrc)
+{
+    VugSrc *src = (VugSrc *)gsrc;
+
+    g_assert(src);
+
+    return src->gfd.revents & src->gfd.events;
+}
+
+static gboolean
+vug_src_dispatch(GSource *gsrc, GSourceFunc cb, gpointer data)
+{
+    VugSrc *src = (VugSrc *)gsrc;
+
+    g_assert(src);
+
+    ((vu_watch_cb)cb)(src->dev, src->gfd.revents, data);
+
+    return G_SOURCE_CONTINUE;
+}
+
+static GSourceFuncs vug_src_funcs = {
+    vug_src_prepare,
+    vug_src_check,
+    vug_src_dispatch,
+    NULL
+};
+
+static GSource *
+vug_source_new(VuDev *dev, int fd, GIOCondition cond,
+               vu_watch_cb vu_cb, gpointer data)
+{
+    GSource *gsrc;
+    VugSrc *src;
+    guint id;
+
+    g_assert(dev);
+    g_assert(fd >= 0);
+    g_assert(vu_cb);
+
+    gsrc = g_source_new(&vug_src_funcs, sizeof(VugSrc));
+    g_source_set_callback(gsrc, (GSourceFunc)vu_cb, data, NULL);
+    src = (VugSrc *)gsrc;
+    src->dev = dev;
+    src->gfd.fd = fd;
+    src->gfd.events = cond;
+
+    g_source_add_poll(gsrc, &src->gfd);
+    id = g_source_attach(gsrc, NULL);
+    g_assert(id);
+    g_source_unref(gsrc);
+
+    return gsrc;
+}
+
+static void
+set_watch(VuDev *vu_dev, int fd, int vu_evt, vu_watch_cb cb, void *pvt)
+{
+    GSource *src;
+    VugDev *dev;
+
+    g_assert(vu_dev);
+    g_assert(fd >= 0);
+    g_assert(cb);
+
+    dev = container_of(vu_dev, VugDev, parent);
+    src = vug_source_new(vu_dev, fd, vu_evt, cb, pvt);
+    g_hash_table_replace(dev->fdmap, GINT_TO_POINTER(fd), src);
+}
+
+static void
+remove_watch(VuDev *vu_dev, int fd)
+{
+    VugDev *dev;
+
+    g_assert(vu_dev);
+    g_assert(fd >= 0);
+
+    dev = container_of(vu_dev, VugDev, parent);
+    g_hash_table_remove(dev->fdmap, GINT_TO_POINTER(fd));
+}
+
+
+static void vug_watch(VuDev *dev, int condition, void *data)
+{
+    if (!vu_dispatch(dev) != 0) {
+        dev->panic(dev, "Error processing vhost message");
+    }
+}
+
+void
+vug_init(VugDev *dev, int socket,
+         vu_panic_cb panic, const VuDevIface *iface)
+{
+    g_assert(dev);
+    g_assert(iface);
+
+    vu_init(&dev->parent, socket, panic, set_watch, remove_watch, iface);
+    dev->fdmap = g_hash_table_new_full(NULL, NULL, NULL,
+                                       (GDestroyNotify) g_source_destroy);
+
+    dev->src = vug_source_new(&dev->parent, socket, G_IO_IN, vug_watch, NULL);
+}
+
+void
+vug_deinit(VugDev *dev)
+{
+    g_assert(dev);
+
+    g_hash_table_unref(dev->fdmap);
+    g_source_unref(dev->src);
+}

contrib/libvhost-user/libvhost-user-glib.h

@@ -0,0 +1,32 @@
+/*
+ * Vhost User library
+ *
+ * Copyright (c) 2016 Nutanix Inc. All rights reserved.
+ * Copyright (c) 2017 Red Hat, Inc.
+ *
+ * Authors:
+ *  Marc-André Lureau <mlureau@redhat.com>
+ *  Felipe Franciosi <felipe@nutanix.com>
+ *
+ * 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 LIBVHOST_USER_GLIB_H
+#define LIBVHOST_USER_GLIB_H
+
+#include <glib.h>
+#include "libvhost-user.h"
+
+typedef struct VugDev {
+    VuDev parent;
+
+    GHashTable *fdmap; /* fd -> gsource */
+    GSource *src;
+} VugDev;
+
+void vug_init(VugDev *dev, int socket,
+              vu_panic_cb panic, const VuDevIface *iface);
+void vug_deinit(VugDev *dev);
+
+#endif /* LIBVHOST_USER_GLIB_H */