From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48778) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fxrvv-000176-A3 for qemu-devel@nongnu.org; Thu, 06 Sep 2018 06:54:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fxrvt-0001ax-VY for qemu-devel@nongnu.org; Thu, 06 Sep 2018 06:54:43 -0400 Received: from mail-qt0-x244.google.com ([2607:f8b0:400d:c0d::244]:38950) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1fxrvt-0001Zc-Nz for qemu-devel@nongnu.org; Thu, 06 Sep 2018 06:54:41 -0400 Received: by mail-qt0-x244.google.com with SMTP id o15-v6so11645461qtk.6 for ; Thu, 06 Sep 2018 03:54:41 -0700 (PDT) References: <20180705200813.2033-1-danielhb413@gmail.com> <20180705200813.2033-4-danielhb413@gmail.com> <153619362876.28231.7392145818127711611@sif> From: Daniel Henrique Barboza Message-ID: <8f69c32d-0e8b-b3ee-b0a2-f7e8f7b6052c@gmail.com> Date: Thu, 6 Sep 2018 07:54:36 -0300 MIME-Version: 1.0 In-Reply-To: <153619362876.28231.7392145818127711611@sif> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [Qemu-devel] [PATCH v8 3/3] qmp hmp: Make system_wakeup check wake-up support and run state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Roth , qemu-devel@nongnu.org Cc: ehabkost@redhat.com, armbru@redhat.com On 09/05/2018 09:27 PM, Michael Roth wrote: > Quoting Daniel Henrique Barboza (2018-07-05 15:08:13) >> 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, the commit before previous created a new QMP API called >> query-current-machine, with 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 | 5 ++++- >> include/sysemu/sysemu.h | 1 + >> qapi/misc.json | 5 ++++- >> qmp.c | 11 ++++++++++- >> vl.c | 2 +- >> 5 files changed, 20 insertions(+), 4 deletions(-) >> >> diff --git a/hmp.c b/hmp.c >> index 41f5e39b72..83a8041d11 100644 >> --- a/hmp.c >> +++ b/hmp.c >> @@ -1169,7 +1169,10 @@ 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/include/sysemu/sysemu.h b/include/sysemu/sysemu.h >> index b921c6f3b7..483f804b36 100644 >> --- a/include/sysemu/sysemu.h >> +++ b/include/sysemu/sysemu.h >> @@ -70,6 +70,7 @@ void qemu_exit_preconfig_request(void); >> void qemu_system_reset_request(ShutdownCause reason); >> void qemu_system_suspend_request(void); >> void qemu_register_suspend_notifier(Notifier *notifier); >> +bool qemu_wakeup_suspend_support(void); >> void qemu_system_wakeup_request(WakeupReason reason); >> void qemu_system_wakeup_enable(WakeupReason reason, bool enabled); >> void qemu_register_wakeup_notifier(Notifier *notifier); >> diff --git a/qapi/misc.json b/qapi/misc.json >> index 266f88cb09..86195d79e9 100644 >> --- a/qapi/misc.json >> +++ b/qapi/misc.json >> @@ -1230,7 +1230,10 @@ >> ## >> # @system_wakeup: >> # >> -# Wakeup guest from suspend. Does nothing in case the guest isn't suspended. >> +# If the guest has wake-up from suspend support enabled >> +# (wakeup-suspend-support flag from query-current-machine), wakeup guest >> +# from suspend if the guest is in SUSPENDED state. Returns an error >> +# otherwise. >> # >> # Since: 1.1 >> # >> diff --git a/qmp.c b/qmp.c >> index 73e46d795f..0673ff1fa5 100644 >> --- a/qmp.c >> +++ b/qmp.c >> @@ -215,7 +215,16 @@ void qmp_cont(Error **errp) >> >> void qmp_system_wakeup(Error **errp) >> { >> - qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); >> + 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; >> + } >> } > Was removing qemu_system_wakeup_request() intentional or did that just get > lost somehow? WOW! That was a mistake! Thanks for spotting it Mike! I'll re-insert it back in the next spin. > >> ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp) >> diff --git a/vl.c b/vl.c >> index 96ad448d57..2af10b75cb 100644 >> --- a/vl.c >> +++ b/vl.c >> @@ -1769,7 +1769,7 @@ void qemu_register_wakeup_notifier(Notifier *notifier) >> notifier_list_add(&wakeup_notifiers, notifier); >> } >> >> -static bool qemu_wakeup_suspend_support(void) >> +bool qemu_wakeup_suspend_support(void) >> { >> return !QLIST_EMPTY(&wakeup_notifiers.notifiers) && acpi_enabled; >> } >> -- >> 2.17.1 >>