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[PATCH V2 14/22] chardev: cpr framework
From: |
Steve Sistare |
Subject: |
[PATCH V2 14/22] chardev: cpr framework |
Date: |
Tue, 5 Jan 2021 07:42:02 -0800 |
Add QEMU_CHAR_FEATURE_CPR for devices that support cpr.
Add the chardev close_on_cpr option for devices that can be closed on cpr
and reopened after exec.
cpr is allowed only if either QEMU_CHAR_FEATURE_CPR or close_on_cpr is set
for all chardevs in the configuration.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
chardev/char.c | 41 ++++++++++++++++++++++++++++++++++++++---
include/chardev/char.h | 5 +++++
migration/cpr.c | 3 +++
qapi/char.json | 5 ++++-
qemu-options.hx | 26 ++++++++++++++++++++++++--
5 files changed, 74 insertions(+), 6 deletions(-)
diff --git a/chardev/char.c b/chardev/char.c
index 77e7ec8..0be551f 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -37,6 +37,7 @@
#include "qemu/help_option.h"
#include "qemu/module.h"
#include "qemu/option.h"
+#include "qemu/env.h"
#include "qemu/id.h"
#include "qemu/coroutine.h"
@@ -226,6 +227,9 @@ static void qemu_char_open(Chardev *chr, ChardevBackend
*backend,
ChardevClass *cc = CHARDEV_GET_CLASS(chr);
/* Any ChardevCommon member would work */
ChardevCommon *common = backend ? backend->u.null.data : NULL;
+ char fdname[40];
+
+ chr->close_on_cpr = (common && common->close_on_cpr);
if (common && common->has_logfile) {
int flags = O_WRONLY | O_CREAT;
@@ -235,7 +239,14 @@ static void qemu_char_open(Chardev *chr, ChardevBackend
*backend,
} else {
flags |= O_TRUNC;
}
- chr->logfd = qemu_open(common->logfile, flags, 0666);
+ snprintf(fdname, sizeof(fdname), "%s_log", chr->label);
+ chr->logfd = getenv_fd(fdname);
+ if (chr->logfd < 0) {
+ chr->logfd = qemu_open(common->logfile, flags, 0666);
+ if (!chr->close_on_cpr) {
+ setenv_fd(fdname, chr->logfd);
+ }
+ }
if (chr->logfd < 0) {
error_setg_errno(errp, errno,
"Unable to open logfile %s",
@@ -286,11 +297,12 @@ 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) {
close(chr->logfd);
+ unsetenv_fdv("%s_log", chr->label);
}
+ g_free(chr->filename);
+ g_free(chr->label);
qemu_mutex_destroy(&chr->chr_write_lock);
}
@@ -490,6 +502,8 @@ void qemu_chr_parse_common(QemuOpts *opts, ChardevCommon
*backend)
backend->has_logappend = true;
backend->logappend = qemu_opt_get_bool(opts, "logappend", false);
+
+ backend->close_on_cpr = qemu_opt_get_bool(opts, "close-on-cpr", false);
}
static const ChardevClass *char_get_class(const char *driver, Error **errp)
@@ -922,6 +936,9 @@ QemuOptsList qemu_chardev_opts = {
},{
.name = "abstract",
.type = QEMU_OPT_BOOL,
+ },{
+ .name = "close-on-cpr",
+ .type = QEMU_OPT_BOOL,
},
{ /* end of list */ }
},
@@ -1163,6 +1180,24 @@ GSource *qemu_chr_timeout_add_ms(Chardev *chr, guint ms,
return source;
}
+static int chr_cpr_capable(Object *obj, void *opaque)
+{
+ Chardev *chr = (Chardev *)obj;
+ Error **errp = opaque;
+
+ if (qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_CPR) || chr->close_on_cpr)
{
+ return 0;
+ }
+ error_setg(errp, "error: chardev %s -> %s is not capable of cpr",
+ chr->label, chr->filename);
+ return 1;
+}
+
+bool qemu_chr_cpr_capable(Error **errp)
+{
+ return !object_child_foreach(get_chardevs_root(), chr_cpr_capable, errp);
+}
+
void qemu_chr_cleanup(void)
{
object_unparent(get_chardevs_root());
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 00589a6..35d04e9 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;
@@ -65,6 +67,7 @@ struct Chardev {
char *filename;
int logfd;
int be_open;
+ bool close_on_cpr;
GSource *gsource;
GMainContext *gcontext;
DECLARE_BITMAP(features, QEMU_CHAR_FEATURE_LAST);
@@ -290,4 +293,6 @@ GSource *qemu_chr_timeout_add_ms(Chardev *chr, guint ms,
/* console.c */
void qemu_chr_parse_vc(QemuOpts *opts, ChardevBackend *backend, Error **errp);
+bool qemu_chr_cpr_capable(Error **errp);
+
#endif
diff --git a/migration/cpr.c b/migration/cpr.c
index 13c5d7c..93f6800 100644
--- a/migration/cpr.c
+++ b/migration/cpr.c
@@ -131,6 +131,9 @@ void cprsave(const char *file, CprMode mode, Error **errp)
no_shutdown = 0;
qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
} else if (restart) {
+ if (!qemu_chr_cpr_capable(errp)) {
+ goto err;
+ }
if (vfio_cprsave()) {
goto err;
}
diff --git a/qapi/char.json b/qapi/char.json
index 8aeedf9..7e0186c 100644
--- a/qapi/char.json
+++ b/qapi/char.json
@@ -204,12 +204,15 @@
# @logfile: The name of a logfile to save output
# @logappend: true to append instead of truncate
# (default to false to truncate)
+# @close-on-cpr: if true, close device's fd on cprsave. defaults to false.
+# since 5.3.
#
# Since: 2.6
##
{ 'struct': 'ChardevCommon',
'data': { '*logfile': 'str',
- '*logappend': 'bool' } }
+ '*logappend': 'bool',
+ '*close-on-cpr': 'bool' } }
##
# @ChardevFile:
diff --git a/qemu-options.hx b/qemu-options.hx
index 455b43b7..1ab5af5 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2956,42 +2956,60 @@ 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"
+ " [,close-on-cpr=on|off]\n"
"-chardev
socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]\n"
"
[,server][,nowait][,telnet][,websocket][,reconnect=seconds][,mux=on|off]\n"
" [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID]
(tcp)\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
socket,id=id,path=path[,server][,nowait][,telnet][,websocket][,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][,close-on-cpr=on|off]
(unix)\n"
"-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n"
" [,localport=localport][,ipv4][,ipv6][,mux=on|off]\n"
- " [,logfile=PATH][,logappend=on|off]\n"
+ " [,logfile=PATH][,logappend=on|off][,close-on-cpr=on|off]\n"
"-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-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"
+ " [,close-on-cpr=on|off]\n"
"-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
#ifdef _WIN32
"-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
#else
"-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
#endif
#ifdef CONFIG_BRLAPI
"-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-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"
+ " [,close-on-cpr=on|off]\n"
"-chardev
tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-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"
+ " [,close-on-cpr=on|off]\n"
"-chardev
parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
#endif
#if defined(CONFIG_SPICE)
"-chardev
spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
"-chardev
spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n"
+ " [,close-on-cpr=on|off]\n"
#endif
, QEMU_ARCH_ALL
)
@@ -3064,6 +3082,10 @@ 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 ``close-on-cpr`` option. If on, the devices's
+ descriptor is closed during cprsave, 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
- Re: [PATCH V2 05/22] vl: memfd-alloc option, (continued)
- [PATCH V2 12/22] vfio-pci: cpr, Steve Sistare, 2021/01/05
- [PATCH V2 16/22] chardev: cpr for pty, Steve Sistare, 2021/01/05
- [PATCH V2 18/22] chardev: cpr for sockets, Steve Sistare, 2021/01/05
- [PATCH V2 19/22] monitor: cpr support, Steve Sistare, 2021/01/05
- [PATCH V2 17/22] chardev: socket accept subroutine, Steve Sistare, 2021/01/05
- [PATCH V2 20/22] cpr: only-cpr-capable option, Steve Sistare, 2021/01/05
- [PATCH V2 22/22] simplify savevm, Steve Sistare, 2021/01/05
- [PATCH V2 14/22] chardev: cpr framework,
Steve Sistare <=
- [PATCH V2 21/22] cpr: maintainers, Steve Sistare, 2021/01/05
- [PATCH V2 02/22] qemu_ram_volatile, Steve Sistare, 2021/01/05
- [PATCH V2 13/22] vhost: reset vhost devices upon cprsave, Steve Sistare, 2021/01/05
- [PATCH V2 01/22] as_flat_walk, Steve Sistare, 2021/01/05
- [PATCH V2 11/22] vfio-pci: refactor for cpr, Steve Sistare, 2021/01/05
- [PATCH V2 15/22] chardev: cpr for simple devices, Steve Sistare, 2021/01/05