| Message ID | 20181205194701.17836-2-danielhb413@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | wakeup-from-suspend and system_wakeup changes | expand |
Daniel Henrique Barboza <danielhb413@gmail.com> writes: > When issuing the qmp/hmp 'system_wakeup' command, what happens in a > nutshell is: > > - qmp_system_wakeup_request set runstate to RUNNING, sets a wakeup_reason > and notify the event > - in the main_loop, all vcpus are paused, a system reset is issued, all > subscribers of wakeup_notifiers receives a notification, vcpus are then > resumed and the wake up QAPI event is fired > > Note that this procedure alone doesn't ensure that the guest will awake > from SUSPENDED state - the subscribers of the wake up event must take > action to resume the guest, otherwise the guest will simply reboot. At > this moment, only the ACPI machines via acpi_pm1_cnt_init and xen_hvm_init > have wake-up from suspend support. > > However, only the presence of 'system_wakeup' is required for QGA to > support 'guest-suspend-ram' and 'guest-suspend-hybrid' at this moment. > This means that the user/management will expect to suspend the guest using > one of those suspend commands and then resume execution using system_wakeup, > regardless of the support offered in system_wakeup in the first place. > > This patch creates a new API called query-current-machine [1], that holds > a new flag called 'wakeup-suspend-support' that indicates if the guest > supports wake up from suspend via system_wakeup. The machine is considered > to implement wake-up support if a call to a new 'qemu_register_wakeup_support' > is made during its init, as it is now being done inside acpi_pm1_cnt_init > and xen_hvm_init. This allows for any other machine type to declare wake-up > support regardless of ACPI state or wakeup_notifiers subscription, making easier > for newer implementations that might have their own mechanisms in the future. > > This is the expected output of query-current-machine when running a x86 > guest: > > {"execute" : "query-current-machine"} > {"return": {"wakeup-suspend-support": true}} > > Running the same x86 guest, but with the --no-acpi option: > > {"execute" : "query-current-machine"} > {"return": {"wakeup-suspend-support": false}} > > This is the output when running a pseries guest: > > {"execute" : "query-current-machine"} > {"return": {"wakeup-suspend-support": false}} > > With this extra tool, management can avoid situations where a guest > that does not have proper suspend/wake capabilities ends up in > inconsistent state (e.g. > https://github.com/open-power-host-os/qemu/issues/31). > > [1] the decision of creating the query-current-machine API is based > on discussions in the QEMU mailing list where it was decided that > query-target wasn't a proper place to store the wake-up flag, neither > was query-machines because this isn't a static property of the > machine object. This new API can then be used to store other > dynamic machine properties that are scattered around the code > ATM. More info at: > https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg04235.html > > Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Reviewed-by: Markus Armbruster <armbru@redhat.com>
diff --git a/hw/acpi/core.c b/hw/acpi/core.c index aafdc61648..52e18d7810 100644 --- a/hw/acpi/core.c +++ b/hw/acpi/core.c @@ -617,6 +617,12 @@ void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent, ar->pm1.cnt.s4_val = s4_val; ar->wakeup.notify = acpi_notify_wakeup; qemu_register_wakeup_notifier(&ar->wakeup); + + /* + * Register wake-up support in QMP query-current-machine API + */ + qemu_register_wakeup_support(); + memory_region_init_io(&ar->pm1.cnt.io, memory_region_owner(parent), &acpi_pm_cnt_ops, ar, "acpi-cnt", 2); memory_region_add_subregion(parent, 4, &ar->pm1.cnt.io); diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c index 935a3676c8..2143d33b18 100644 --- a/hw/i386/xen/xen-hvm.c +++ b/hw/i386/xen/xen-hvm.c @@ -1405,6 +1405,11 @@ void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory) state->wakeup.notify = xen_wakeup_notifier; qemu_register_wakeup_notifier(&state->wakeup); + /* + * Register wake-up support in QMP query-current-machine API + */ + qemu_register_wakeup_support(); + rc = xen_map_ioreq_server(state); if (rc < 0) { goto err; diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h index 8d6095d98b..0446adacc6 100644 --- a/include/sysemu/sysemu.h +++ b/include/sysemu/sysemu.h @@ -77,6 +77,7 @@ void qemu_register_suspend_notifier(Notifier *notifier); void qemu_system_wakeup_request(WakeupReason reason); void qemu_system_wakeup_enable(WakeupReason reason, bool enabled); void qemu_register_wakeup_notifier(Notifier *notifier); +void qemu_register_wakeup_support(void); void qemu_system_shutdown_request(ShutdownCause reason); void qemu_system_powerdown_request(void); void qemu_register_powerdown_notifier(Notifier *notifier); diff --git a/qapi/misc.json b/qapi/misc.json index 6c1c5c0a37..deb982ed38 100644 --- a/qapi/misc.json +++ b/qapi/misc.json @@ -2008,6 +2008,30 @@ ## { 'command': 'query-machines', 'returns': ['MachineInfo'] } +## +# @CurrentMachineParams: +# +# Information describing the running machine parameters. +# +# @wakeup-suspend-support: true if the machine supports wake up from +# suspend +# +# Since: 4.0 +## +{ 'struct': 'CurrentMachineParams', + 'data': { 'wakeup-suspend-support': 'bool'} } + +## +# @query-current-machine: +# +# Return information on the current virtual machine. +# +# Returns: CurrentMachineParams +# +# Since: 4.0 +## +{ 'command': 'query-current-machine', 'returns': 'CurrentMachineParams' } + ## # @CpuDefinitionInfo: # diff --git a/vl.c b/vl.c index a5ae5f23d2..8f5b3ef4e9 100644 --- a/vl.c +++ b/vl.c @@ -192,6 +192,7 @@ bool boot_strict; uint8_t *boot_splash_filedata; size_t boot_splash_filedata_size; uint8_t qemu_extra_params_fw[2]; +bool wakeup_suspend_enabled; int icount_align_option; @@ -1780,6 +1781,24 @@ void qemu_register_wakeup_notifier(Notifier *notifier) notifier_list_add(&wakeup_notifiers, notifier); } +void qemu_register_wakeup_support(void) +{ + wakeup_suspend_enabled = true; +} + +static bool qemu_wakeup_suspend_enabled(void) +{ + return wakeup_suspend_enabled; +} + +CurrentMachineParams *qmp_query_current_machine(Error **errp) +{ + CurrentMachineParams *params = g_malloc0(sizeof(*params)); + params->wakeup_suspend_support = qemu_wakeup_suspend_enabled(); + + return params; +} + void qemu_system_killed(int signal, pid_t pid) { shutdown_signal = signal;
When issuing the qmp/hmp 'system_wakeup' command, what happens in a nutshell is: - qmp_system_wakeup_request set runstate to RUNNING, sets a wakeup_reason and notify the event - in the main_loop, all vcpus are paused, a system reset is issued, all subscribers of wakeup_notifiers receives a notification, vcpus are then resumed and the wake up QAPI event is fired Note that this procedure alone doesn't ensure that the guest will awake from SUSPENDED state - the subscribers of the wake up event must take action to resume the guest, otherwise the guest will simply reboot. At this moment, only the ACPI machines via acpi_pm1_cnt_init and xen_hvm_init have wake-up from suspend support. However, only the presence of 'system_wakeup' is required for QGA to support 'guest-suspend-ram' and 'guest-suspend-hybrid' at this moment. This means that the user/management will expect to suspend the guest using one of those suspend commands and then resume execution using system_wakeup, regardless of the support offered in system_wakeup in the first place. This patch creates a new API called query-current-machine [1], that holds a new flag called 'wakeup-suspend-support' that indicates if the guest supports wake up from suspend via system_wakeup. The machine is considered to implement wake-up support if a call to a new 'qemu_register_wakeup_support' is made during its init, as it is now being done inside acpi_pm1_cnt_init and xen_hvm_init. This allows for any other machine type to declare wake-up support regardless of ACPI state or wakeup_notifiers subscription, making easier for newer implementations that might have their own mechanisms in the future. This is the expected output of query-current-machine when running a x86 guest: {"execute" : "query-current-machine"} {"return": {"wakeup-suspend-support": true}} Running the same x86 guest, but with the --no-acpi option: {"execute" : "query-current-machine"} {"return": {"wakeup-suspend-support": false}} This is the output when running a pseries guest: {"execute" : "query-current-machine"} {"return": {"wakeup-suspend-support": false}} With this extra tool, management can avoid situations where a guest that does not have proper suspend/wake capabilities ends up in inconsistent state (e.g. https://github.com/open-power-host-os/qemu/issues/31). [1] the decision of creating the query-current-machine API is based on discussions in the QEMU mailing list where it was decided that query-target wasn't a proper place to store the wake-up flag, neither was query-machines because this isn't a static property of the machine object. This new API can then be used to store other dynamic machine properties that are scattered around the code ATM. More info at: https://lists.gnu.org/archive/html/qemu-devel/2018-05/msg04235.html Reported-by: Balamuruhan S <bala24@linux.vnet.ibm.com> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- hw/acpi/core.c | 6 ++++++ hw/i386/xen/xen-hvm.c | 5 +++++ include/sysemu/sysemu.h | 1 + qapi/misc.json | 24 ++++++++++++++++++++++++ vl.c | 19 +++++++++++++++++++ 5 files changed, 55 insertions(+)