Add QEMU_CHAR_FEATURE_CPR for devices that support cpr by preserving an
open descriptor across exec. Add the chardev reopen-on-cpr option for
devices that should be closed on cpr and reopened after exec.
Enable cpr for a chardev if it has QEMU_CHAR_FEATURE_CPR and reopen-on-cpr
is false. Allow cpr-save if either QEMU_CHAR_FEATURE_CPR or reopen-on-cpr
is true for all chardevs in the configuration.
Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
---
chardev/char.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
include/chardev/char.h | 5 +++++
qapi/char.json | 7 ++++++-
qemu-options.hx | 26 ++++++++++++++++++++++----
4 files changed, 78 insertions(+), 9 deletions(-)
diff --git a/chardev/char.c b/chardev/char.c
index 0169d8d..ef3f196 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -36,9 +36,11 @@
#include "qemu/help_option.h"
#include "qemu/module.h"
#include "qemu/option.h"
+#include "migration/cpr.h"
#include "qemu/id.h"
#include "qemu/coroutine.h"
#include "qemu/yank.h"
+#include "sysemu/sysemu.h"
#include "chardev-internal.h"
@@ -236,26 +238,55 @@ int qemu_chr_add_client(Chardev *s, int fd)
static void qemu_char_open(Chardev *chr, ChardevBackend *backend,
bool *be_opened, Error **errp)
{
+ ERRP_GUARD();
+ g_autofree char *fdname = NULL;
+
ChardevClass *cc = CHARDEV_GET_CLASS(chr);
/* Any ChardevCommon member would work */
ChardevCommon *common = backend ? backend->u.null.data : NULL;
+ bool has_logfile = (common && common->has_logfile);
+ bool has_feature_cpr;
- if (common && common->has_logfile) {
+ if (has_logfile) {
int flags = O_WRONLY;
+ fdname = g_strdup_printf("%s_log", chr->label);
if (common->has_logappend &&
common->logappend) {
flags |= O_APPEND;
} else {
flags |= O_TRUNC;
}
- chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
+ chr->logfd = cpr_find_fd(fdname, 0);
+ if (chr->logfd < 0) {
+ chr->logfd = qemu_create(common->logfile, flags, 0666, errp);
+ }
if (chr->logfd < 0) {
return;
}
}
+ chr->reopen_on_cpr = (common && common->reopen_on_cpr);
+
if (cc->open) {
cc->open(chr, backend, be_opened, errp);
+ if (*errp) {
+ return;
+ }
+ }
+
+ /* Evaluate this after the open method sets the feature */
+ has_feature_cpr = qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_CPR);
+ chr->cpr_enabled = !chr->reopen_on_cpr && has_feature_cpr;
+
+ if (!chr->reopen_on_cpr && !has_feature_cpr) {
+ chr->cpr_blocker = NULL;
+ error_setg(&chr->cpr_blocker,
+ "chardev %s -> %s does not allow cpr. See reopen-on-cpr.",
+ chr->label, chr->filename);
+ cpr_add_blocker(&chr->cpr_blocker, errp, CPR_MODE_RESTART, 0);
+
+ } else if (chr->cpr_enabled && has_logfile) {
+ cpr_resave_fd(fdname, 0, chr->logfd, errp);
}
}
@@ -297,11 +328,16 @@ static void char_finalize(Object *obj)
if (chr->be) {
chr->be->chr = NULL;
}
- g_free(chr->filename);
- g_free(chr->label);
if (chr->logfd != -1) {
+ g_autofree char *fdname = g_strdup_printf("%s_log", chr->label);
+ if (chr->cpr_enabled) {
+ cpr_delete_fd(fdname, 0);
+ }
close(chr->logfd);
}
+ cpr_del_blocker(&chr->cpr_blocker);
+ g_free(chr->filename);
+ g_free(chr->label);
qemu_mutex_destroy(&chr->chr_write_lock);
}
@@ -501,6 +537,8 @@ void qemu_chr_parse_common(QemuOpts *opts, ChardevCommon
*backend)
backend->has_logappend = true;
backend->logappend = qemu_opt_get_bool(opts, "logappend", false);
+
+ backend->reopen_on_cpr = qemu_opt_get_bool(opts, "reopen-on-cpr", false);
}
static const ChardevClass *char_get_class(const char *driver, Error **errp)
@@ -942,6 +980,9 @@ QemuOptsList qemu_chardev_opts = {
},{
.name = "abstract",
.type = QEMU_OPT_BOOL,
+ },{
+ .name = "reopen-on-cpr",
+ .type = QEMU_OPT_BOOL,
#endif
},
{ /* end of list */ }
diff --git a/include/chardev/char.h b/include/chardev/char.h
index a319b5f..bbf2560 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -50,6 +50,8 @@ typedef enum {
/* Whether the gcontext can be changed after calling
* qemu_chr_be_update_read_handlers() */
QEMU_CHAR_FEATURE_GCONTEXT,
+ /* Whether the device supports cpr */
+ QEMU_CHAR_FEATURE_CPR,
QEMU_CHAR_FEATURE_LAST,
} ChardevFeature;
@@ -67,6 +69,9 @@ struct Chardev {
int be_open;
/* used to coordinate the chardev-change special-case: */
bool handover_yank_instance;
+ bool reopen_on_cpr;
+ bool cpr_enabled;
+ Error *cpr_blocker;
GSource *gsource;
GMainContext *gcontext;
DECLARE_BITMAP(features, QEMU_CHAR_FEATURE_LAST);
diff --git a/qapi/char.json b/qapi/char.json
index 923dc50..0c3558e 100644
--- a/qapi/char.json
+++ b/qapi/char.json
@@ -204,12 +204,17 @@
# @logfile: The name of a logfile to save output
# @logappend: true to append instead of truncate
# (default to false to truncate)
+# @reopen-on-cpr: if true, close device's fd on cpr-save and reopen it after
+# cpr-exec. Set this to allow CPR on a device that does not
+# support QEMU_CHAR_FEATURE_CPR. defaults to false.
+# since 7.1.
#
# Since: 2.6
##
{ 'struct': 'ChardevCommon',
'data': { '*logfile': 'str',
- '*logappend': 'bool' } }
+ '*logappend': 'bool',
+ '*reopen-on-cpr': 'bool' } }
##
# @ChardevFile:
diff --git a/qemu-options.hx b/qemu-options.hx
index 1b49360..2f4bb2b 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3291,43 +3291,57 @@ DEFHEADING(Character device options:)
DEF("chardev", HAS_ARG, QEMU_OPTION_chardev,
"-chardev help\n"
- "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ "-chardev
null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off][,reopen-on-cpr=on|off]\n"
"-chardev
socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n"
"
[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n"
- " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID]
(tcp)\n"
+ "
[,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID][,reopen-on-cpr=on|off]
(tcp)\n"
"-chardev
socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n"
- "
[,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off]
(unix)\n"
+ "
[,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off][,reopen-on-cpr=on|off]
(unix)\n"
"-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
"
[,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n"
- " [,logfile=PATH][,logappend=on|off]\n"
+ " [,logfile=PATH][,logappend=on|off][,reopen-on-cpr=on|off]\n"
"-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n"
" [,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#ifdef _WIN32
"-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
"-chardev
serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
#else
"-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#endif
#ifdef CONFIG_BRLAPI
"-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#endif
#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \
|| defined(__NetBSD__) || defined(__OpenBSD__) ||
defined(__DragonFly__)
"-chardev
serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#endif
#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
"-chardev
parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#endif
#if defined(CONFIG_SPICE)
"-chardev
spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
"-chardev
spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
+ " [,reopen-on-cpr=on|off]\n"
#endif
, QEMU_ARCH_ALL
)
@@ -3402,6 +3416,10 @@ The general form of a character device option is:
``logappend`` option controls whether the log file will be truncated
or appended to when opened.
+ Every backend supports the ``reopen-on-cpr`` option. If on, the
+ devices's descriptor is closed during cpr-save, and reopened after exec.
+ This is useful for devices that do not support cpr.
+
The available backends are:
``-chardev null,id=id``
--
1.8.3.1
