It is okay to register legacy backends in the middle of xen_bus_init().
All that the registration does is record the existence of the backend
in xenstore.
This makes it possible to remove them from the build without introducing
undefined symbols in xen_be_init(). It also removes the need for the
backend_register callback, whose only purpose is to avoid registering
nonfunctional backends.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
Message-ID: <20240509170044.190795-8-pbonz...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
include/hw/xen/xen-legacy-backend.h | 14 ++------------
include/hw/xen/xen_pvdev.h | 1 -
hw/9pfs/xen-9p-backend.c | 8 +++++++-
hw/display/xenfb.c | 8 +++++++-
hw/usb/xen-usb.c | 14 ++++----------
hw/xen/xen-legacy-backend.c | 16 ----------------
6 files changed, 20 insertions(+), 41 deletions(-)
diff --git a/include/hw/xen/xen-legacy-backend.h
b/include/hw/xen/xen-legacy-backend.h
index 2cca1747786..979c4ea04c5 100644
--- a/include/hw/xen/xen-legacy-backend.h
+++ b/include/hw/xen/xen-legacy-backend.h
@@ -66,18 +66,8 @@ static inline void xen_be_unmap_grant_ref(struct
XenLegacyDevice *xendev,
return xen_be_unmap_grant_refs(xendev, ptr, &ref, 1);
}
-/* actual backend drivers */
-extern struct XenDevOps xen_console_ops; /* xen_console.c */
-extern struct XenDevOps xen_kbdmouse_ops; /* xen_framebuffer.c */
-extern struct XenDevOps xen_framebuffer_ops; /* xen_framebuffer.c */
-extern struct XenDevOps xen_blkdev_ops; /* xen_disk.c */
-#ifdef CONFIG_VIRTFS
-extern struct XenDevOps xen_9pfs_ops; /* xen-9p-backend.c */
-#endif
-extern struct XenDevOps xen_netdev_ops; /* xen_nic.c */
-#ifdef CONFIG_USB_LIBUSB
-extern struct XenDevOps xen_usb_ops; /* xen-usb.c */
-#endif
+/* backend drivers not included in all machines */
+extern struct XenDevOps xen_framebuffer_ops; /* xenfb.c */
/* configuration (aka xenbus setup) */
void xen_config_cleanup(void);
diff --git a/include/hw/xen/xen_pvdev.h b/include/hw/xen/xen_pvdev.h
index ddad4b9f36a..fdf84f47af1 100644
--- a/include/hw/xen/xen_pvdev.h
+++ b/include/hw/xen/xen_pvdev.h
@@ -29,7 +29,6 @@ struct XenDevOps {
const char *node);
void (*frontend_changed)(struct XenLegacyDevice *xendev,
const char *node);
- int (*backend_register)(void);
};
struct XenLegacyDevice {
diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c
index 4aa9c8c736d..a3ac53f989e 100644
--- a/hw/9pfs/xen-9p-backend.c
+++ b/hw/9pfs/xen-9p-backend.c
@@ -513,7 +513,7 @@ static void xen_9pfs_alloc(struct XenLegacyDevice *xendev)
xenstore_write_be_int(xendev, "max-ring-page-order", MAX_RING_ORDER);
}
-struct XenDevOps xen_9pfs_ops = {
+static struct XenDevOps xen_9pfs_ops = {
.size = sizeof(Xen9pfsDev),
.flags = DEVOPS_FLAG_NEED_GNTDEV,
.alloc = xen_9pfs_alloc,
@@ -522,3 +522,9 @@ struct XenDevOps xen_9pfs_ops = {
.disconnect = xen_9pfs_disconnect,
.free = xen_9pfs_free,
};
+
+static void xen_9pfs_register_backend(void)
+{
+ xen_be_register("9pfs", &xen_9pfs_ops);
+}
+xen_backend_init(xen_9pfs_register_backend);
diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
index b2130a0d700..27536bfce0c 100644
--- a/hw/display/xenfb.c
+++ b/hw/display/xenfb.c
@@ -972,7 +972,7 @@ static void fb_event(struct XenLegacyDevice *xendev)
/* -------------------------------------------------------------------- */
-struct XenDevOps xen_kbdmouse_ops = {
+static struct XenDevOps xen_kbdmouse_ops = {
.size = sizeof(struct XenInput),
.init = input_init,
.initialise = input_initialise,
@@ -995,3 +995,9 @@ static const GraphicHwOps xenfb_ops = {
.gfx_update = xenfb_update,
.ui_info = xenfb_ui_info,
};
+
+static void xen_vkbd_register_backend(void)
+{
+ xen_be_register("vkbd", &xen_kbdmouse_ops);
+}
+xen_backend_init(xen_vkbd_register_backend);
diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
index 09ec326aeae..416623f956a 100644
--- a/hw/usb/xen-usb.c
+++ b/hw/usb/xen-usb.c
@@ -1083,7 +1083,7 @@ static void usbback_event(struct XenLegacyDevice *xendev)
qemu_bh_schedule(usbif->bh);
}
-struct XenDevOps xen_usb_ops = {
+static struct XenDevOps xen_usb_ops = {
.size = sizeof(struct usbback_info),
.flags = DEVOPS_FLAG_NEED_GNTDEV,
.init = usbback_init,
@@ -1095,15 +1095,9 @@ struct XenDevOps xen_usb_ops = {
.event = usbback_event,
};
-#else /* USBIF_SHORT_NOT_OK */
-
-static int usbback_not_supported(void)
+static void xen_usb_register_backend(void)
{
- return -EINVAL;
+ xen_be_register("qusb", &xen_usb_ops);
}
-
-struct XenDevOps xen_usb_ops = {
- .backend_register = usbback_not_supported,
-};
-
+xen_backend_init(xen_usb_register_backend);
#endif
diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
index 124dd5f3d68..6f0b300a421 100644
--- a/hw/xen/xen-legacy-backend.c
+++ b/hw/xen/xen-legacy-backend.c
@@ -622,27 +622,11 @@ void xen_be_init(void)
qbus_set_bus_hotplug_handler(xen_sysbus);
xen_set_dynamic_sysbus();
-
- xen_be_register("vkbd", &xen_kbdmouse_ops);
-#ifdef CONFIG_VIRTFS
- xen_be_register("9pfs", &xen_9pfs_ops);
-#endif
-#ifdef CONFIG_USB_LIBUSB
- xen_be_register("qusb", &xen_usb_ops);
-#endif
}
int xen_be_register(const char *type, struct XenDevOps *ops)
{
char path[50];
- int rc;
-
- if (ops->backend_register) {
- rc = ops->backend_register();
- if (rc) {
- return rc;
- }
- }
snprintf(path, sizeof(path), "device-model/%u/backends/%s", xen_domid,
type);
--
2.45.0
