Re: [Xen-devel] [PATCH V2] qemu-xen: HVM domain S3 bugfix

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Paolo Bonzini wrote:
> Il 29/08/2013 10:25, Liu, Jinsong ha scritto:
>> Currently HVM S3 has a bug coming from the difference between
>> qemu-traditioanl and qemu-xen. For qemu-traditional, the way
>> to resume from hvm s3 is via 'xl trigger' command. However,
>> for qemu-xen, the way to resume from hvm s3 inherited from
>> standard qemu, i.e. via QMP, and it doesn't work under Xen.
>> 
>> The root cause is, for qemu-xen, 'xl trigger' command didn't reset
>> devices, while QMP didn't unpause hvm domain though they did qemu
>> system reset.
>> 
>> We have 2 patches to fix the HVM S3 bug: qemu-xen patch and xl patch.
>> This patch is the qemu-xen patch. It registers a wakeup later notify,
>> so that when 'xl trigger' command invokes QMP system_wakeup and after
>> qemu system reset, it hypercalls to hypervisor to unpause domain,
>> then 
>> hvm S3 resumes successfully.
>> 
>> Signed-off-by: Liu Jinsong <jinsong.liu@xxxxxxxxx>
>> ---
>>  vl.c      |   13 +++++++++++++
>>  xen-all.c |    9 +++++++++
>>  2 files changed, 22 insertions(+), 0 deletions(-)
>> 
>> diff --git a/vl.c b/vl.c
>> index 5314f55..aeebd83 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -1478,6 +1478,8 @@ static NotifierList suspend_notifiers =
>>      NOTIFIER_LIST_INITIALIZER(suspend_notifiers);
>>  static NotifierList wakeup_notifiers =
>>      NOTIFIER_LIST_INITIALIZER(wakeup_notifiers);
>> +static NotifierList wakeup_later_notifiers =
>> +    NOTIFIER_LIST_INITIALIZER(wakeup_later_notifiers);
>>  static uint32_t wakeup_reason_mask = ~0;
>>  static RunState vmstop_requested = RUN_STATE_MAX;
>> 
>> @@ -1625,6 +1627,11 @@ static void qemu_system_suspend(void)
>>      monitor_protocol_event(QEVENT_SUSPEND, NULL);
>>  }
>> 
>> +static void qemu_system_wakeup(void)
>> +{
>> +    notifier_list_notify(&wakeup_later_notifiers, NULL); +}
>> +
>>  void qemu_system_suspend_request(void)
>>  {
>>      if (runstate_check(RUN_STATE_SUSPENDED)) {
>> @@ -1668,6 +1675,11 @@ void qemu_register_wakeup_notifier(Notifier
>>      *notifier) notifier_list_add(&wakeup_notifiers, notifier);  }
>> 
>> +void qemu_register_wakeup_later_notifier(Notifier *notifier) +{
>> +    notifier_list_add(&wakeup_later_notifiers, notifier); +}
>> +
>>  void qemu_system_killed(int signal, pid_t pid)
>>  {
>>      shutdown_signal = signal;
>> @@ -1744,6 +1756,7 @@ static bool main_loop_should_exit(void)
>>          cpu_synchronize_all_states();
>>          qemu_system_reset(VMRESET_SILENT);
>>          resume_all_vcpus();
>> +        qemu_system_wakeup();
> 
> Does Xen work if the hypercall is placed before resume_all_vcpus?  In
> this case, you can just move the wakeup_notifiers invocation from
> qemu_system_wakeup_request to here, and avoid introducing a separate
> list. 
> 
> Paolo
> 

No problem. Have updated and sent out.

Thanks,
Jinsong
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