From: David Woodhouse <d...@amazon.co.uk>
Ensure that we have a XenBackendInstance for every device regardless
of whether it was "discovered" in XenStore or created directly in QEMU.
This allows the backend_list to be a source of truth about whether a
given backend exists, and allows us to reject duplicates.
This also cleans up the fact that backend drivers were calling
xen_backend_set_device() with a XenDevice immediately after calling
qdev_realize_and_unref() on it, when it wasn't theirs to play with any
more.
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
hw/block/xen-block.c | 1 -
hw/char/xen_console.c | 2 +-
hw/xen/xen-backend.c | 78 ++++++++++++++++++++++++++----------
hw/xen/xen-bus.c | 8 ++++
include/hw/xen/xen-backend.h | 3 ++
5 files changed, 69 insertions(+), 23 deletions(-)
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index a07cd7eb5d..9262338535 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -975,7 +975,6 @@ static void xen_block_device_create(XenBackendInstance
*backend,
goto fail;
}
- xen_backend_set_device(backend, xendev);
return;
fail:
diff --git a/hw/char/xen_console.c b/hw/char/xen_console.c
index bd20be116c..2825b8c511 100644
--- a/hw/char/xen_console.c
+++ b/hw/char/xen_console.c
@@ -468,7 +468,7 @@ static void xen_console_device_create(XenBackendInstance
*backend,
Chardev *cd = NULL;
struct qemu_xs_handle *xsh = xenbus->xsh;
- if (qemu_strtoul(name, NULL, 10, &number)) {
+ if (qemu_strtoul(name, NULL, 10, &number) || number >= INT_MAX) {
error_setg(errp, "failed to parse name '%s'", name);
goto fail;
}
diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c
index b9bf70a9f5..dcb4329258 100644
--- a/hw/xen/xen-backend.c
+++ b/hw/xen/xen-backend.c
@@ -101,22 +101,28 @@ static XenBackendInstance
*xen_backend_list_find(XenDevice *xendev)
return NULL;
}
-bool xen_backend_exists(const char *type, const char *name)
+static XenBackendInstance *xen_backend_lookup(const XenBackendImpl *impl,
const char *name)
{
- const XenBackendImpl *impl = xen_backend_table_lookup(type);
XenBackendInstance *backend;
- if (!impl) {
- return false;
- }
-
QLIST_FOREACH(backend, &backend_list, entry) {
if (backend->impl == impl && !strcmp(backend->name, name)) {
- return true;
+ return backend;
}
}
- return false;
+ return NULL;
+}
+
+bool xen_backend_exists(const char *type, const char *name)
+{
+ const XenBackendImpl *impl = xen_backend_table_lookup(type);
+
+ if (!impl) {
+ return false;
+ }
+
+ return !!xen_backend_lookup(impl, name);
}
static void xen_backend_list_remove(XenBackendInstance *backend)
@@ -138,11 +144,10 @@ void xen_backend_device_create(XenBus *xenbus, const char
*type,
backend = g_new0(XenBackendInstance, 1);
backend->xenbus = xenbus;
backend->name = g_strdup(name);
-
- impl->create(backend, opts, errp);
-
backend->impl = impl;
xen_backend_list_add(backend);
+
+ impl->create(backend, opts, errp);
}
XenBus *xen_backend_get_bus(XenBackendInstance *backend)
@@ -155,13 +160,6 @@ const char *xen_backend_get_name(XenBackendInstance
*backend)
return backend->name;
}
-void xen_backend_set_device(XenBackendInstance *backend,
- XenDevice *xendev)
-{
- g_assert(!backend->xendev);
- backend->xendev = xendev;
-}
-
XenDevice *xen_backend_get_device(XenBackendInstance *backend)
{
return backend->xendev;
@@ -178,9 +176,7 @@ bool xen_backend_try_device_destroy(XenDevice *xendev,
Error **errp)
}
impl = backend->impl;
- if (backend->xendev) {
- impl->destroy(backend, errp);
- }
+ impl->destroy(backend, errp);
xen_backend_list_remove(backend);
g_free(backend->name);
@@ -188,3 +184,43 @@ bool xen_backend_try_device_destroy(XenDevice *xendev,
Error **errp)
return true;
}
+
+bool xen_backend_device_realized(XenDevice *xendev, Error **errp)
+{
+ XenDeviceClass *xendev_class = XEN_DEVICE_GET_CLASS(xendev);
+ const char *type = xendev_class->backend ? :
object_get_typename(OBJECT(xendev));
+ const XenBackendImpl *impl = xen_backend_table_lookup(type);
+ XenBackendInstance *backend;
+
+ if (!impl) {
+ return false;
+ }
+
+ backend = xen_backend_lookup(impl, xendev->name);
+ if (backend) {
+ if (backend->xendev && backend->xendev != xendev) {
+ error_setg(errp, "device %s/%s already exists", type,
xendev->name);
+ return false;
+ }
+ backend->xendev = xendev;
+ return true;
+ }
+
+ backend = g_new0(XenBackendInstance, 1);
+ backend->xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev)));
+ backend->xendev = xendev;
+ backend->name = g_strdup(xendev->name);
+ backend->impl = impl;
+
+ xen_backend_list_add(backend);
+ return true;
+}
+
+void xen_backend_device_unrealized(XenDevice *xendev)
+{
+ XenBackendInstance *backend = xen_backend_list_find(xendev);
+
+ if (backend) {
+ backend->xendev = NULL;
+ }
+}
diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c
index 0da2aa219a..0b232d1f94 100644
--- a/hw/xen/xen-bus.c
+++ b/hw/xen/xen-bus.c
@@ -359,6 +359,8 @@ static void xen_bus_realize(BusState *bus, Error **errp)
g_free(type);
g_free(key);
+
+ xen_bus_enumerate(xenbus);
return;
fail:
@@ -958,6 +960,8 @@ static void xen_device_unrealize(DeviceState *dev)
trace_xen_device_unrealize(type, xendev->name);
+ xen_backend_device_unrealized(xendev);
+
if (xendev->exit.notify) {
qemu_remove_exit_notifier(&xendev->exit);
xendev->exit.notify = NULL;
@@ -1024,6 +1028,10 @@ static void xen_device_realize(DeviceState *dev, Error
**errp)
goto unrealize;
}
+ if (!xen_backend_device_realized(xendev, errp)) {
+ goto unrealize;
+ }
+
trace_xen_device_realize(type, xendev->name);
xendev->xsh = qemu_xen_xs_open();
diff --git a/include/hw/xen/xen-backend.h b/include/hw/xen/xen-backend.h
index 0f01631ae7..3f1e764c51 100644
--- a/include/hw/xen/xen-backend.h
+++ b/include/hw/xen/xen-backend.h
@@ -38,4 +38,7 @@ void xen_backend_device_create(XenBus *xenbus, const char
*type,
const char *name, QDict *opts, Error **errp);
bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp);
+bool xen_backend_device_realized(XenDevice *xendev, Error **errp);
+void xen_backend_device_unrealized(XenDevice *xendev);
+
#endif /* HW_XEN_BACKEND_H */
--
2.40.1
