Add an interface to register a blocker for cpr-save for one or more modes.
Devices and options that do not support a cpr mode can register a blocker,
and cpr-save will fail with a descriptive error message. Conversely, if
such a device is deleted and un-registers its blocker, cpr will be allowed
again.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
MAINTAINERS | 1 +
include/migration/cpr.h | 6 ++++
migration/cpr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++
stubs/cpr.c | 23 ++++++++++++++
stubs/meson.build | 1 +
5 files changed, 110 insertions(+)
create mode 100644 stubs/cpr.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 9273891..1e4e72f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3159,6 +3159,7 @@ S: Maintained
F: include/migration/cpr.h
F: migration/cpr.c
F: qapi/cpr.json
+F: stubs/cpr.c
Record/replay
M: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
diff --git a/include/migration/cpr.h b/include/migration/cpr.h
index 1b6c82f..dfe5a1d 100644
--- a/include/migration/cpr.h
+++ b/include/migration/cpr.h
@@ -13,4 +13,10 @@
void cpr_set_mode(CprMode mode);
CprMode cpr_get_mode(void);
+#define CPR_MODE_ALL CPR_MODE__MAX
+
+int cpr_add_blocker(Error **reasonp, Error **errp, CprMode mode, ...);
+int cpr_add_blocker_str(const char *reason, Error **errp, CprMode mode, ...);
+void cpr_del_blocker(Error **reasonp);
+
#endif
diff --git a/migration/cpr.c b/migration/cpr.c
index 24b0bcc..c1da784 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -29,12 +29,91 @@ void cpr_set_mode(CprMode mode)
cpr_mode = mode;
}
+static GSList *cpr_blockers[CPR_MODE__MAX];
+
+/*
+ * Add blocker for each mode in varargs list, or for all modes if CPR_MODE_ALL
+ * is specified. Caller terminates the list with 0 or CPR_MODE_ALL. This
+ * function takes ownership of *reasonp, and frees it on error, or in
+ * cpr_del_blocker. errp is set in a later patch.
+ */
+int cpr_add_blocker(Error **reasonp, Error **errp, CprMode mode, ...)
+{
+ int modes = 0;
+ va_list ap;
+ ERRP_GUARD();
+
+ va_start(ap, mode);
+ while (mode != CPR_MODE_NONE && mode != CPR_MODE_ALL) {
+ assert(mode > CPR_MODE_NONE && mode < CPR_MODE__MAX);
+ modes |= BIT(mode);
+ mode = va_arg(ap, CprMode);
+ }
+ va_end(ap);
+ if (mode == CPR_MODE_ALL) {
+ modes = BIT(CPR_MODE__MAX) - 1;
+ }
+
+ for (mode = 0; mode < CPR_MODE__MAX; mode++) {
+ if (modes & BIT(mode)) {
+ cpr_blockers[mode] = g_slist_prepend(cpr_blockers[mode], *reasonp);
+ }
+ }
+ return 0;
+}
+
+/*
+ * Delete the blocker from all modes it is associated with.
+ */
+void cpr_del_blocker(Error **reasonp)
+{
+ CprMode mode;
+
+ if (*reasonp) {
+ for (mode = 0; mode < CPR_MODE__MAX; mode++) {
+ cpr_blockers[mode] = g_slist_remove(cpr_blockers[mode], *reasonp);
+ }
+ error_free(*reasonp);
+ *reasonp = NULL;
+ }
+}
+
+/*
+ * Add a blocker which will not be deleted. Simpler for some callers.
+ */
+int cpr_add_blocker_str(const char *msg, Error **errp, CprMode mode, ...)
+{
+ int ret;
+ va_list ap;
+ Error *reason = NULL;
+
+ error_setg(&reason, "%s", msg);
+ va_start(ap, mode);
+ ret = cpr_add_blocker(&reason, errp, mode, ap);
+ va_end(ap);
+ return ret;
+}
+
+static bool cpr_is_blocked(Error **errp, CprMode mode)
+{
+ if (cpr_blockers[mode]) {
+ error_propagate(errp, error_copy(cpr_blockers[mode]->data));
+ return true;
+ }
+
+ return false;
+}
+
void qmp_cpr_save(const char *filename, CprMode mode, Error **errp)
{
int ret;
QEMUFile *f;
int saved_vm_running = runstate_is_running();
+ if (cpr_is_blocked(errp, mode)) {
+ return;
+ }
+
if (global_state_store()) {
error_setg(errp, "Error saving global state");
return;
diff --git a/stubs/cpr.c b/stubs/cpr.c
new file mode 100644
index 0000000..06a9a1c
--- /dev/null
+++ b/stubs/cpr.c
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2022 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "migration/cpr.h"
+
+int cpr_add_blocker(Error **reasonp, Error **errp, CprMode mode, ...)
+{
+ return 0;
+}
+
+int cpr_add_blocker_str(const char *reason, Error **errp, CprMode mode, ...)
+{
+ return 0;
+}
+
+void cpr_del_blocker(Error **reasonp)
+{
+}
diff --git a/stubs/meson.build b/stubs/meson.build
index 6f80fec..0d7565b 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -4,6 +4,7 @@ stub_ss.add(files('blk-exp-close-all.c'))
stub_ss.add(files('blockdev-close-all-bdrv-states.c'))
stub_ss.add(files('change-state-handler.c'))
stub_ss.add(files('cmos.c'))
+stub_ss.add(files('cpr.c'))
stub_ss.add(files('cpu-get-clock.c'))
stub_ss.add(files('cpus-get-virtual-clock.c'))
stub_ss.add(files('qemu-timer-notify-cb.c'))
--
1.8.3.1
