The error_report function can include the guest name in any
messages it prints. The qemu_log function has no equivalent
behaviour.
This introduces support for a "workload name" in the new
messages API, which in the case of system emulators will
be the guest name. The possibility of defining a workload
name for other binaries is left as an exercise for the
future.
This change has no impact on the output of the error_report
function, but will change the qemu_log function. This can
be easily seen with the 'log' trace backend, and how it is
now more closely matching error_report output.
Before:
# qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
After:
# qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
blah qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
blah qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
include/qemu/error-report.h | 3 ---
include/qemu/message.h | 10 ++++++++++
system/vl.c | 6 ++++--
util/error-report.c | 7 -------
util/message.c | 12 +++++++++++-
5 files changed, 25 insertions(+), 13 deletions(-)
diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index c8000778ec..ffc305f828 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -70,7 +70,4 @@ void error_init(const char *argv0);
fmt, ##__VA_ARGS__); \
})
-extern bool error_with_guestname;
-extern const char *error_guest_name;
-
#endif
diff --git a/include/qemu/message.h b/include/qemu/message.h
index 0a06421f77..cfc3c92648 100644
--- a/include/qemu/message.h
+++ b/include/qemu/message.h
@@ -5,6 +5,7 @@
enum QMessageFormatFlags {
QMESSAGE_FORMAT_TIMESTAMP = (1 << 0),
+ QMESSAGE_FORMAT_WORKLOAD_NAME = (1 << 1),
};
/**
@@ -16,6 +17,15 @@ enum QMessageFormatFlags {
*/
void qmessage_set_format(int flags);
+/**
+ * qmessage_set_workload_name:
+ * @name: the name of the workload
+ *
+ * Set the workload name, which for a system emulator
+ * will be the guest VM name.
+ */
+void qmessage_set_workload_name(const char *name);
+
/**
* qmessage_context_print:
* @fp: file to emit the prefix on
diff --git a/system/vl.c b/system/vl.c
index 696dd92669..fee6fdf7b1 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -818,7 +818,9 @@ static void configure_msg(QemuOpts *opts)
if (qemu_opt_get_bool(opts, "timestamp", false)) {
flags |= QMESSAGE_FORMAT_TIMESTAMP;
}
- error_with_guestname = qemu_opt_get_bool(opts, "guest-name", false);
+ if (qemu_opt_get_bool(opts, "guest-name", false)) {
+ flags |= QMESSAGE_FORMAT_WORKLOAD_NAME;
+ }
qmessage_set_format(flags);
}
@@ -3520,7 +3522,7 @@ void qemu_init(int argc, char **argv)
exit(1);
}
/* Capture guest name if -msg guest-name is used later */
- error_guest_name = qemu_opt_get(opts, "guest");
+ qmessage_set_workload_name(qemu_opt_get(opts, "guest"));
break;
case QEMU_OPTION_prom_env:
if (nb_prom_envs >= MAX_PROM_ENVS) {
diff --git a/util/error-report.c b/util/error-report.c
index 719f059494..c40cdf3bb3 100644
--- a/util/error-report.c
+++ b/util/error-report.c
@@ -25,8 +25,6 @@ typedef enum {
REPORT_TYPE_INFO,
} report_type;
-bool error_with_guestname;
-const char *error_guest_name;
typedef void (*error_print_func)(void *opaque, const char *fmt, ...);
typedef void (*error_print_vfunc)(void *opaque, const char *fmt, va_list ap);
@@ -218,11 +216,6 @@ static void vreport(report_type type, const char *fmt, va_list ap)
qmessage_context_print(stderr);
}
- /* Only prepend guest name if -msg guest-name and -name guest=... are set */
- if (error_with_guestname && error_guest_name && !cur) {
- print_func(print_opaque, "%s ", error_guest_name);
- }
-
print_loc(!!cur, print_func, print_opaque);
switch (type) {
diff --git a/util/message.c b/util/message.c
index ef70e08c5f..a91c008e08 100644
--- a/util/message.c
+++ b/util/message.c
@@ -6,18 +6,28 @@
#include "monitor/monitor.h"
static int message_format;
+static char *message_workloadname;
void qmessage_set_format(int flags)
{
message_format = flags;
}
-void qmessage_context_print(FILE *fp)
+void qmessage_set_workload_name(const char *name)
{
+ message_workloadname = g_strdup(name);
+}
+void qmessage_context_print(FILE *fp)
+{
if (message_format & QMESSAGE_FORMAT_TIMESTAMP) {
g_autoptr(GDateTime) dt = g_date_time_new_now_utc();
g_autofree char *timestr = g_date_time_format_iso8601(dt);
fprintf(fp, "%s ", timestr);
}
+
+ if ((message_format & QMESSAGE_FORMAT_WORKLOAD_NAME) &&
+ message_workloadname) {
+ fprintf(fp, "%s ", message_workloadname);
+ }
}
--
2.50.1
* Daniel P. Berrangé (berrange@redhat.com) wrote:
> The error_report function can include the guest name in any
> messages it prints. The qemu_log function has no equivalent
> behaviour.
>
> This introduces support for a "workload name" in the new
> messages API, which in the case of system emulators will
> be the guest name. The possibility of defining a workload
> name for other binaries is left as an exercise for the
> future.
>
> This change has no impact on the output of the error_report
> function, but will change the qemu_log function. This can
> be easily seen with the 'log' trace backend, and how it is
> now more closely matching error_report output.
>
> Before:
>
> # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
>
> After:
>
> # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> blah qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> blah qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Are you going to want to escape that? I see later you're adding []'s around it,
which makes it feel like you want to end up with it parsable, but if some nasty
person does:
-name ']})🐧({['
then things get confusing; I guess you're hoping that whoever calls qemu will
be careful not to allow that.
Dave
> ---
> include/qemu/error-report.h | 3 ---
> include/qemu/message.h | 10 ++++++++++
> system/vl.c | 6 ++++--
> util/error-report.c | 7 -------
> util/message.c | 12 +++++++++++-
> 5 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> index c8000778ec..ffc305f828 100644
> --- a/include/qemu/error-report.h
> +++ b/include/qemu/error-report.h
> @@ -70,7 +70,4 @@ void error_init(const char *argv0);
> fmt, ##__VA_ARGS__); \
> })
>
> -extern bool error_with_guestname;
> -extern const char *error_guest_name;
> -
> #endif
> diff --git a/include/qemu/message.h b/include/qemu/message.h
> index 0a06421f77..cfc3c92648 100644
> --- a/include/qemu/message.h
> +++ b/include/qemu/message.h
> @@ -5,6 +5,7 @@
>
> enum QMessageFormatFlags {
> QMESSAGE_FORMAT_TIMESTAMP = (1 << 0),
> + QMESSAGE_FORMAT_WORKLOAD_NAME = (1 << 1),
> };
>
> /**
> @@ -16,6 +17,15 @@ enum QMessageFormatFlags {
> */
> void qmessage_set_format(int flags);
>
> +/**
> + * qmessage_set_workload_name:
> + * @name: the name of the workload
> + *
> + * Set the workload name, which for a system emulator
> + * will be the guest VM name.
> + */
> +void qmessage_set_workload_name(const char *name);
> +
> /**
> * qmessage_context_print:
> * @fp: file to emit the prefix on
> diff --git a/system/vl.c b/system/vl.c
> index 696dd92669..fee6fdf7b1 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -818,7 +818,9 @@ static void configure_msg(QemuOpts *opts)
> if (qemu_opt_get_bool(opts, "timestamp", false)) {
> flags |= QMESSAGE_FORMAT_TIMESTAMP;
> }
> - error_with_guestname = qemu_opt_get_bool(opts, "guest-name", false);
> + if (qemu_opt_get_bool(opts, "guest-name", false)) {
> + flags |= QMESSAGE_FORMAT_WORKLOAD_NAME;
> + }
> qmessage_set_format(flags);
> }
>
> @@ -3520,7 +3522,7 @@ void qemu_init(int argc, char **argv)
> exit(1);
> }
> /* Capture guest name if -msg guest-name is used later */
> - error_guest_name = qemu_opt_get(opts, "guest");
> + qmessage_set_workload_name(qemu_opt_get(opts, "guest"));
> break;
> case QEMU_OPTION_prom_env:
> if (nb_prom_envs >= MAX_PROM_ENVS) {
> diff --git a/util/error-report.c b/util/error-report.c
> index 719f059494..c40cdf3bb3 100644
> --- a/util/error-report.c
> +++ b/util/error-report.c
> @@ -25,8 +25,6 @@ typedef enum {
> REPORT_TYPE_INFO,
> } report_type;
>
> -bool error_with_guestname;
> -const char *error_guest_name;
>
> typedef void (*error_print_func)(void *opaque, const char *fmt, ...);
> typedef void (*error_print_vfunc)(void *opaque, const char *fmt, va_list ap);
> @@ -218,11 +216,6 @@ static void vreport(report_type type, const char *fmt, va_list ap)
> qmessage_context_print(stderr);
> }
>
> - /* Only prepend guest name if -msg guest-name and -name guest=... are set */
> - if (error_with_guestname && error_guest_name && !cur) {
> - print_func(print_opaque, "%s ", error_guest_name);
> - }
> -
> print_loc(!!cur, print_func, print_opaque);
>
> switch (type) {
> diff --git a/util/message.c b/util/message.c
> index ef70e08c5f..a91c008e08 100644
> --- a/util/message.c
> +++ b/util/message.c
> @@ -6,18 +6,28 @@
> #include "monitor/monitor.h"
>
> static int message_format;
> +static char *message_workloadname;
>
> void qmessage_set_format(int flags)
> {
> message_format = flags;
> }
>
> -void qmessage_context_print(FILE *fp)
> +void qmessage_set_workload_name(const char *name)
> {
> + message_workloadname = g_strdup(name);
> +}
>
> +void qmessage_context_print(FILE *fp)
> +{
> if (message_format & QMESSAGE_FORMAT_TIMESTAMP) {
> g_autoptr(GDateTime) dt = g_date_time_new_now_utc();
> g_autofree char *timestr = g_date_time_format_iso8601(dt);
> fprintf(fp, "%s ", timestr);
> }
> +
> + if ((message_format & QMESSAGE_FORMAT_WORKLOAD_NAME) &&
> + message_workloadname) {
> + fprintf(fp, "%s ", message_workloadname);
> + }
> }
> --
> 2.50.1
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
On Thu, Sep 11, 2025 at 08:27:36PM +0000, Dr. David Alan Gilbert wrote:
> * Daniel P. Berrangé (berrange@redhat.com) wrote:
> > The error_report function can include the guest name in any
> > messages it prints. The qemu_log function has no equivalent
> > behaviour.
> >
> > This introduces support for a "workload name" in the new
> > messages API, which in the case of system emulators will
> > be the guest name. The possibility of defining a workload
> > name for other binaries is left as an exercise for the
> > future.
> >
> > This change has no impact on the output of the error_report
> > function, but will change the qemu_log function. This can
> > be easily seen with the 'log' trace backend, and how it is
> > now more closely matching error_report output.
> >
> > Before:
> >
> > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> > qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> > qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
> >
> > After:
> >
> > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> > blah qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> > blah qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
>
> Are you going to want to escape that? I see later you're adding []'s around it,
> which makes it feel like you want to end up with it parsable, but if some nasty
> person does:
>
> -name ']})🐧({['
>
> then things get confusing; I guess you're hoping that whoever calls qemu will
> be careful not to allow that.
I was considering the log output to be human targetted, rather
than something to be parsed. IOW, if users want to confuse
themselves with wierd names, that's their own (unwise) decision.
If we added ecaping of the name, it'd probably even more difficult
to read for a human, even if we make it a bit easier for humans ?
TL;DR: do we care about parseability here, or just humans reading ?
With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
* Daniel P. Berrangé (berrange@redhat.com) wrote:
> On Thu, Sep 11, 2025 at 08:27:36PM +0000, Dr. David Alan Gilbert wrote:
> > * Daniel P. Berrangé (berrange@redhat.com) wrote:
> > > The error_report function can include the guest name in any
> > > messages it prints. The qemu_log function has no equivalent
> > > behaviour.
> > >
> > > This introduces support for a "workload name" in the new
> > > messages API, which in the case of system emulators will
> > > be the guest name. The possibility of defining a workload
> > > name for other binaries is left as an exercise for the
> > > future.
> > >
> > > This change has no impact on the output of the error_report
> > > function, but will change the qemu_log function. This can
> > > be easily seen with the 'log' trace backend, and how it is
> > > now more closely matching error_report output.
> > >
> > > Before:
> > >
> > > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> > > qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> > > qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> > > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
> > >
> > > After:
> > >
> > > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
> > > blah qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish
> > > blah qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none>
> > > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory
> > >
> > > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> >
> > Are you going to want to escape that? I see later you're adding []'s around it,
> > which makes it feel like you want to end up with it parsable, but if some nasty
> > person does:
> >
> > -name ']})🐧({['
> >
> > then things get confusing; I guess you're hoping that whoever calls qemu will
> > be careful not to allow that.
>
> I was considering the log output to be human targetted, rather
> than something to be parsed. IOW, if users want to confuse
> themselves with wierd names, that's their own (unwise) decision.
>
> If we added ecaping of the name, it'd probably even more difficult
> to read for a human, even if we make it a bit easier for humans ?
>
> TL;DR: do we care about parseability here, or just humans reading ?
If it's just humans that's fine; if anywhere were documenting the output
format then it should probably have a warning.
Dave
> With regards,
> Daniel
> --
> |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
> |: https://libvirt.org -o- https://fstop138.berrange.com :|
> |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
>
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ dave @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
On 9/10/25 18:03, Daniel P. Berrangé wrote: > The error_report function can include the guest name in any > messages it prints. The qemu_log function has no equivalent > behaviour. > > This introduces support for a "workload name" in the new > messages API, which in the case of system emulators will > be the guest name. The possibility of defining a workload > name for other binaries is left as an exercise for the > future. > > This change has no impact on the output of the error_report > function, but will change the qemu_log function. This can > be easily seen with the 'log' trace backend, and how it is > now more closely matching error_report output. > > Before: > > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*' > qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish > qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none> > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory > > After: > > # qemu-system-x86_64 -msg guest-name=on -name blah -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*' > blah qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x55b3af3fd870 dir=fish > blah qcrypto_tls_creds_get_path TLS creds path creds=0x55b3af3fd870 filename=ca-cert.pem path=<none> > blah qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory > > Signed-off-by: Daniel P. Berrangé<berrange@redhat.com> > --- > include/qemu/error-report.h | 3 --- > include/qemu/message.h | 10 ++++++++++ > system/vl.c | 6 ++++-- > util/error-report.c | 7 ------- > util/message.c | 12 +++++++++++- > 5 files changed, 25 insertions(+), 13 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
© 2016 - 2025 Red Hat, Inc.