For further vhost-user-blk backend-transfer migration realization we
want to give it (vhost-user-blk) a possibility (and responsibility) to
decide when do connect.
For incoming migration we'll need to postpone connect at least until
early stage of migrate-incoming command, when we already know all
migration parameters and can decide, are we going to do incoming
backend-transfer (and get chardev fd from incoming stream), or we
finally need to connect.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
chardev/char-fe.c | 32 ++++++++++++++++++++++++-----
hw/core/qdev-properties-system.c | 26 ++++++++++++++++++++---
include/chardev/char-fe.h | 6 +++++-
include/hw/qdev-properties-system.h | 3 +++
4 files changed, 58 insertions(+), 9 deletions(-)
diff --git a/chardev/char-fe.c b/chardev/char-fe.c
index 973fed5bea..d77d36960e 100644
--- a/chardev/char-fe.c
+++ b/chardev/char-fe.c
@@ -189,15 +189,26 @@ bool qemu_chr_fe_backend_open(CharBackend *be)
return be->chr && be->chr->be_open;
}
-bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
+bool qemu_chr_fe_init_ex(CharBackend *b, Chardev *s, bool connect,
+ Error **errp)
{
unsigned int tag = 0;
- if (!qemu_chr_connect(s, errp)) {
- return false;
- }
-
if (s) {
+ if (connect) {
+ if (!qemu_chr_connect(s, errp)) {
+ return false;
+ }
+ } else {
+ /* DEFINE_PROP_CHR_NO_CONNECT */
+ if (!s->connect_postponed) {
+ error_setg(errp,
+ "Chardev %s does not support postponed connect",
+ s->label);
+ return false;
+ }
+ }
+
if (CHARDEV_IS_MUX(s)) {
MuxChardev *d = MUX_CHARDEV(s);
@@ -210,6 +221,12 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
} else {
s->be = b;
}
+ } else {
+ /*
+ * connect=false comes only from DEFINE_PROP_CHR_NO_CONNECT,
+ * through do_set_chr, which provides chardev ptr.
+ */
+ assert(connect);
}
b->fe_is_open = false;
@@ -218,6 +235,11 @@ bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
return true;
}
+bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp)
+{
+ return qemu_chr_fe_init_ex(b, s, true, errp);
+}
+
void qemu_chr_fe_deinit(CharBackend *b, bool del)
{
assert(b);
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 1f810b7ddf..6a0572ca03 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -266,8 +266,8 @@ static void get_chr(Object *obj, Visitor *v, const char *name, void *opaque,
g_free(p);
}
-static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
- Error **errp)
+static void do_set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
+ bool connect, Error **errp)
{
ERRP_GUARD();
const Property *prop = opaque;
@@ -297,13 +297,25 @@ static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
if (s == NULL) {
error_setg(errp, "Property '%s.%s' can't find value '%s'",
object_get_typename(obj), name, str);
- } else if (!qemu_chr_fe_init(be, s, errp)) {
+ } else if (!qemu_chr_fe_init_ex(be, s, connect, errp)) {
error_prepend(errp, "Property '%s.%s' can't take value '%s': ",
object_get_typename(obj), name, str);
}
g_free(str);
}
+static void set_chr(Object *obj, Visitor *v, const char *name, void *opaque,
+ Error **errp)
+{
+ do_set_chr(obj, v, name, opaque, true, errp);
+}
+
+static void set_chr_no_connect(Object *obj, Visitor *v, const char *name,
+ void *opaque, Error **errp)
+{
+ do_set_chr(obj, v, name, opaque, false, errp);
+}
+
static void release_chr(Object *obj, const char *name, void *opaque)
{
const Property *prop = opaque;
@@ -320,6 +332,14 @@ const PropertyInfo qdev_prop_chr = {
.release = release_chr,
};
+const PropertyInfo qdev_prop_chr_no_connect = {
+ .type = "str",
+ .description = "ID of a chardev to use as a backend",
+ .get = get_chr,
+ .set = set_chr_no_connect,
+ .release = release_chr,
+};
+
/* --- mac address --- */
/*
diff --git a/include/chardev/char-fe.h b/include/chardev/char-fe.h
index 8ef05b3dd0..32013623b3 100644
--- a/include/chardev/char-fe.h
+++ b/include/chardev/char-fe.h
@@ -25,15 +25,19 @@ struct CharBackend {
};
/**
- * qemu_chr_fe_init:
+ * qemu_chr_fe_init(_ex):
*
* Initializes a front end for the given CharBackend and
* Chardev. Call qemu_chr_fe_deinit() to remove the association and
* release the driver.
+ * Call qemu_chr_connect(), except for the case when connect=false
+ * parameter set for _ex() version.
*
* Returns: false on error.
*/
bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp);
+bool qemu_chr_fe_init_ex(CharBackend *b, Chardev *s, bool connect,
+ Error **errp);
/**
* qemu_chr_fe_deinit:
diff --git a/include/hw/qdev-properties-system.h b/include/hw/qdev-properties-system.h
index 9601a11a09..41f68f60b9 100644
--- a/include/hw/qdev-properties-system.h
+++ b/include/hw/qdev-properties-system.h
@@ -7,6 +7,7 @@ bool qdev_prop_sanitize_s390x_loadparm(uint8_t *loadparm, const char *str,
Error **errp);
extern const PropertyInfo qdev_prop_chr;
+extern const PropertyInfo qdev_prop_chr_no_connect;
extern const PropertyInfo qdev_prop_macaddr;
extern const PropertyInfo qdev_prop_reserved_region;
extern const PropertyInfo qdev_prop_multifd_compression;
@@ -39,6 +40,8 @@ extern const PropertyInfo qdev_prop_virtio_gpu_output_list;
#define DEFINE_PROP_CHR(_n, _s, _f) \
DEFINE_PROP(_n, _s, _f, qdev_prop_chr, CharBackend)
+#define DEFINE_PROP_CHR_NO_CONNECT(_n, _s, _f) \
+ DEFINE_PROP(_n, _s, _f, qdev_prop_chr_no_connect, CharBackend)
#define DEFINE_PROP_NETDEV(_n, _s, _f) \
DEFINE_PROP(_n, _s, _f, qdev_prop_netdev, NICPeers)
#define DEFINE_PROP_DRIVE(_n, _s, _f) \
--
2.48.1