Re: [Qemu-devel] [PATCH v7 3/3] qmp.c: system_wakeup: runstate and wake-up support check
Daniel Henrique Barboza writes: > On 05/18/2018 05:48 AM, Markus Armbruster wrote: >> This affects both QMP and HMP. Let's rephrase the title to >> >> qmp hmp: Make system_wakeup check wake-up support and run state >> >> Can do that in my tree. > > I can rename the commit name, and handle the other suggestions you > made below, in the respin I'll end up making due to the changes > about to happen in patch 1. No problem. > > I've cited 'query-target' all over the patch series too. All these > references > will need to be changed with the new API of the flag (query-machines seems > to be the favorite so far). It's easier to just resend everything > up-to-date. Makes my life easier :) However, I'd recommend to give people a bit more time to chime in on the proper home of wakeup-suspend-support before you respin.
Re: [Qemu-devel] [PATCH v7 3/3] qmp.c: system_wakeup: runstate and wake-up support check
On 05/18/2018 05:48 AM, Markus Armbruster wrote:
This affects both QMP and HMP. Let's rephrase the title to
qmp hmp: Make system_wakeup check wake-up support and run state
Can do that in my tree.
I can rename the commit name, and handle the other suggestions you
made below, in the respin I'll end up making due to the changes
about to happen in patch 1. No problem.
I've cited 'query-target' all over the patch series too. All these
references
will need to be changed with the new API of the flag (query-machines seems
to be the favorite so far). It's easier to just resend everything
up-to-date.
Thanks,
Daniel
Daniel Henrique Barboza writes:
The qmp/hmp command 'system_wakeup' is simply a direct call to
'qemu_system_wakeup_request' from vl.c. This function verifies if
runstate is SUSPENDED and if the wake up reason is valid before
proceeding. However, no error or warning is thrown if any of those
pre-requirements isn't met. There is no way for the caller to
differentiate between a successful wakeup or an error state caused
when trying to wake up a guest that wasn't suspended.
This means that system_wakeup is silently failing, which can be
considered a bug. Adding error handling isn't an API break in this
case - applications that didn't check the result will remain broken,
the ones that check it will have a chance to deal with it.
Adding to that, recent changes in query-target added a new flag called
"... the commit before previous extended query-target with a new flag..."
wakeup-suspend-support that indicates if the guest has the capability
of waking up from suspended state. Although such guest will never
reach SUSPENDED state and erroring it out in this scenario would
suffice, it is more informative for the user to differentiate between a
failure because the guest isn't suspended versus a failure because the
guest does not have support for wake up at all.
All this considered, this patch changes qmp_system_wakeup to:
- check if the guest has the capability to wake-up from suspend. If
not, error out informing about the lack of support;
- make the runstate verification before proceeding to call
qemu_system_wakeup_request, firing up an error message if the user tries
to wake up a machine that isn't in SUSPENDED state.
After this patch, this is the output of system_wakeup in a guest that
does not have wake-up from suspend support (ppc64):
(qemu) system_wakeup
wake-up from suspend is not supported by this guest
(qemu)
And this is the output of system_wakeup in a x86 guest that has the
support but isn't suspended:
(qemu) system_wakeup
Unable to wake up: guest is not in suspended state
(qemu)
The examples are a nice touch.
Reported-by: Balamuruhan S
Signed-off-by: Daniel Henrique Barboza
---
hmp.c | 4 +++-
qapi/misc.json | 3 ++-
qmp.c | 10 ++
3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/hmp.c b/hmp.c
index ef93f4878b..d177d14cc9 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1156,7 +1156,9 @@ void hmp_cont(Monitor *mon, const QDict *qdict)
void hmp_system_wakeup(Monitor *mon, const QDict *qdict)
{
-qmp_system_wakeup(NULL);
+Error *err = NULL;
Blank line between declaration and statement, please. Happy to touch
this up in my tree.
+qmp_system_wakeup(&err);
+hmp_handle_error(mon, &err);
}
void hmp_nmi(Monitor *mon, const QDict *qdict)
diff --git a/qapi/misc.json b/qapi/misc.json
index efba0449a6..73bfc3e436 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -1247,7 +1247,8 @@
#
# If the guest has wake-up from suspend support enabled
# (wakeup-suspend-support flag from query-target), wakeup guest from
-# suspend. Does nothing otherwise.
+# suspend if the guest is in SUSPENDED state. Returns an error
+# otherwise.
#
# Since: 1.1
#
diff --git a/qmp.c b/qmp.c
index 25fdc9a5b2..5366e963ad 100644
--- a/qmp.c
+++ b/qmp.c
@@ -205,6 +205,16 @@ void qmp_cont(Error **errp)
void qmp_system_wakeup(Error **errp)
{
+if (!qemu_wakeup_suspend_support()) {
+error_setg(errp,
+ "wake-up from suspend is not supported by this guest");
+return;
+}
+if (!runstate_check(RUN_STATE_SUSPENDED)) {
+error_setg(errp,
+ "Unable to wake up: guest is not in suspended state");
+return;
+}
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
}
Re: [Qemu-devel] [PATCH v7 3/3] qmp.c: system_wakeup: runstate and wake-up support check
This affects both QMP and HMP. Let's rephrase the title to
qmp hmp: Make system_wakeup check wake-up support and run state
Can do that in my tree.
Daniel Henrique Barboza writes:
> The qmp/hmp command 'system_wakeup' is simply a direct call to
> 'qemu_system_wakeup_request' from vl.c. This function verifies if
> runstate is SUSPENDED and if the wake up reason is valid before
> proceeding. However, no error or warning is thrown if any of those
> pre-requirements isn't met. There is no way for the caller to
> differentiate between a successful wakeup or an error state caused
> when trying to wake up a guest that wasn't suspended.
>
> This means that system_wakeup is silently failing, which can be
> considered a bug. Adding error handling isn't an API break in this
> case - applications that didn't check the result will remain broken,
> the ones that check it will have a chance to deal with it.
>
> Adding to that, recent changes in query-target added a new flag called
"... the commit before previous extended query-target with a new flag..."
> wakeup-suspend-support that indicates if the guest has the capability
> of waking up from suspended state. Although such guest will never
> reach SUSPENDED state and erroring it out in this scenario would
> suffice, it is more informative for the user to differentiate between a
> failure because the guest isn't suspended versus a failure because the
> guest does not have support for wake up at all.
>
> All this considered, this patch changes qmp_system_wakeup to:
>
> - check if the guest has the capability to wake-up from suspend. If
> not, error out informing about the lack of support;
>
> - make the runstate verification before proceeding to call
> qemu_system_wakeup_request, firing up an error message if the user tries
> to wake up a machine that isn't in SUSPENDED state.
>
> After this patch, this is the output of system_wakeup in a guest that
> does not have wake-up from suspend support (ppc64):
>
> (qemu) system_wakeup
> wake-up from suspend is not supported by this guest
> (qemu)
>
> And this is the output of system_wakeup in a x86 guest that has the
> support but isn't suspended:
>
> (qemu) system_wakeup
> Unable to wake up: guest is not in suspended state
> (qemu)
The examples are a nice touch.
> Reported-by: Balamuruhan S
> Signed-off-by: Daniel Henrique Barboza
> ---
> hmp.c | 4 +++-
> qapi/misc.json | 3 ++-
> qmp.c | 10 ++
> 3 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/hmp.c b/hmp.c
> index ef93f4878b..d177d14cc9 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -1156,7 +1156,9 @@ void hmp_cont(Monitor *mon, const QDict *qdict)
>
> void hmp_system_wakeup(Monitor *mon, const QDict *qdict)
> {
> -qmp_system_wakeup(NULL);
> +Error *err = NULL;
Blank line between declaration and statement, please. Happy to touch
this up in my tree.
> +qmp_system_wakeup(&err);
> +hmp_handle_error(mon, &err);
> }
>
> void hmp_nmi(Monitor *mon, const QDict *qdict)
> diff --git a/qapi/misc.json b/qapi/misc.json
> index efba0449a6..73bfc3e436 100644
> --- a/qapi/misc.json
> +++ b/qapi/misc.json
> @@ -1247,7 +1247,8 @@
> #
> # If the guest has wake-up from suspend support enabled
> # (wakeup-suspend-support flag from query-target), wakeup guest from
> -# suspend. Does nothing otherwise.
> +# suspend if the guest is in SUSPENDED state. Returns an error
> +# otherwise.
> #
> # Since: 1.1
> #
> diff --git a/qmp.c b/qmp.c
> index 25fdc9a5b2..5366e963ad 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -205,6 +205,16 @@ void qmp_cont(Error **errp)
>
> void qmp_system_wakeup(Error **errp)
> {
> +if (!qemu_wakeup_suspend_support()) {
> +error_setg(errp,
> + "wake-up from suspend is not supported by this guest");
> +return;
> +}
> +if (!runstate_check(RUN_STATE_SUSPENDED)) {
> +error_setg(errp,
> + "Unable to wake up: guest is not in suspended state");
> +return;
> +}
> qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
> }
[Qemu-devel] [PATCH v7 3/3] qmp.c: system_wakeup: runstate and wake-up support check
The qmp/hmp command 'system_wakeup' is simply a direct call to
'qemu_system_wakeup_request' from vl.c. This function verifies if
runstate is SUSPENDED and if the wake up reason is valid before
proceeding. However, no error or warning is thrown if any of those
pre-requirements isn't met. There is no way for the caller to
differentiate between a successful wakeup or an error state caused
when trying to wake up a guest that wasn't suspended.
This means that system_wakeup is silently failing, which can be
considered a bug. Adding error handling isn't an API break in this
case - applications that didn't check the result will remain broken,
the ones that check it will have a chance to deal with it.
Adding to that, recent changes in query-target added a new flag called
wakeup-suspend-support that indicates if the guest has the capability
of waking up from suspended state. Although such guest will never
reach SUSPENDED state and erroring it out in this scenario would
suffice, it is more informative for the user to differentiate between a
failure because the guest isn't suspended versus a failure because the
guest does not have support for wake up at all.
All this considered, this patch changes qmp_system_wakeup to:
- check if the guest has the capability to wake-up from suspend. If
not, error out informing about the lack of support;
- make the runstate verification before proceeding to call
qemu_system_wakeup_request, firing up an error message if the user tries
to wake up a machine that isn't in SUSPENDED state.
After this patch, this is the output of system_wakeup in a guest that
does not have wake-up from suspend support (ppc64):
(qemu) system_wakeup
wake-up from suspend is not supported by this guest
(qemu)
And this is the output of system_wakeup in a x86 guest that has the
support but isn't suspended:
(qemu) system_wakeup
Unable to wake up: guest is not in suspended state
(qemu)
Reported-by: Balamuruhan S
Signed-off-by: Daniel Henrique Barboza
---
hmp.c | 4 +++-
qapi/misc.json | 3 ++-
qmp.c | 10 ++
3 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/hmp.c b/hmp.c
index ef93f4878b..d177d14cc9 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1156,7 +1156,9 @@ void hmp_cont(Monitor *mon, const QDict *qdict)
void hmp_system_wakeup(Monitor *mon, const QDict *qdict)
{
-qmp_system_wakeup(NULL);
+Error *err = NULL;
+qmp_system_wakeup(&err);
+hmp_handle_error(mon, &err);
}
void hmp_nmi(Monitor *mon, const QDict *qdict)
diff --git a/qapi/misc.json b/qapi/misc.json
index efba0449a6..73bfc3e436 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -1247,7 +1247,8 @@
#
# If the guest has wake-up from suspend support enabled
# (wakeup-suspend-support flag from query-target), wakeup guest from
-# suspend. Does nothing otherwise.
+# suspend if the guest is in SUSPENDED state. Returns an error
+# otherwise.
#
# Since: 1.1
#
diff --git a/qmp.c b/qmp.c
index 25fdc9a5b2..5366e963ad 100644
--- a/qmp.c
+++ b/qmp.c
@@ -205,6 +205,16 @@ void qmp_cont(Error **errp)
void qmp_system_wakeup(Error **errp)
{
+if (!qemu_wakeup_suspend_support()) {
+error_setg(errp,
+ "wake-up from suspend is not supported by this guest");
+return;
+}
+if (!runstate_check(RUN_STATE_SUSPENDED)) {
+error_setg(errp,
+ "Unable to wake up: guest is not in suspended state");
+return;
+}
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
}
--
2.14.3
