Re: [Qemu-devel] [Qemu-ppc] [PATCH v10] migration: spapr: migrate pending_events of spapr state

[Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>]

On 05/16/2017 01:25 AM, David Gibson wrote:
> On Mon, May 15, 2017 at 10:10:52AM -0300, Daniel Henrique Barboza wrote:
>> From: Jianjun Duan <duanj@linux.vnet.ibm.com>
>>
>> In racing situations between hotplug events and migration operation,
>> a rtas hotplug event could have not yet be delivered to the source
>> guest when migration is started. In this case the pending_events of
>> spapr state need be transmitted to the target so that the hotplug
>> event can be finished on the target.
>>
>> All the different fields of the events are encoded as defined by
>> PAPR. We can migrate them as uint8_t binary stream without any
>> concerns about data padding or endianess.
>>
>> pending_events is put in a subsection in the spapr state VMSD to make
>> sure migration across different versions is not broken.
>>
>> Signed-off-by: Jianjun Duan <duanj@linux.vnet.ibm.com>
>> Signed-off-by: Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>
> Ok, thanks for splitting this out, but you don't seem to have
> addressed the other comments I had on this patch as presented before.

Sorry, I haven't noticed you had previous comments on this patch. I'll 
address
them and re-send.


Daniel

>
>> ---
>>   hw/ppc/spapr.c         | 33 +++++++++++++++++++++++++++++++++
>>   hw/ppc/spapr_events.c  | 24 +++++++++++++-----------
>>   include/hw/ppc/spapr.h |  3 ++-
>>   3 files changed, 48 insertions(+), 12 deletions(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index 80d12d0..8cfdc71 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -1437,6 +1437,38 @@ static bool version_before_3(void *opaque, int version_id)
>>       return version_id < 3;
>>   }
>>   
>> +static bool spapr_pending_events_needed(void *opaque)
>> +{
>> +    sPAPRMachineState *spapr = (sPAPRMachineState *)opaque;
>> +    return !QTAILQ_EMPTY(&spapr->pending_events);
>> +}
>> +
>> +static const VMStateDescription vmstate_spapr_event_entry = {
>> +    .name = "spapr_event_log_entry",
>> +    .version_id = 1,
>> +    .minimum_version_id = 1,
>> +    .fields = (VMStateField[]) {
>> +        VMSTATE_INT32(log_type, sPAPREventLogEntry),
>> +        VMSTATE_BOOL(exception, sPAPREventLogEntry),
> I'd like some more information to convince me there isn't redundant
> data here.
>
>> +        VMSTATE_UINT32(data_size, sPAPREventLogEntry),
>> +        VMSTATE_VARRAY_UINT32_ALLOC(data, sPAPREventLogEntry, data_size,
>> +                                    0, vmstate_info_uint8, uint8_t),
> And I think this should be VBUFFER rather than VARRAY to avoid the
> data type change.
>
>> +        VMSTATE_END_OF_LIST()
>> +    },
>> +};
>> +
>> +static const VMStateDescription vmstate_spapr_pending_events = {
>> +    .name = "spapr_pending_events",
>> +    .version_id = 1,
>> +    .minimum_version_id = 1,
>> +    .needed = spapr_pending_events_needed,
>> +    .fields = (VMStateField[]) {
>> +        VMSTATE_QTAILQ_V(pending_events, sPAPRMachineState, 1,
>> +                         vmstate_spapr_event_entry, sPAPREventLogEntry, next),
>> +        VMSTATE_END_OF_LIST()
>> +    },
>> +};
>> +
>>   static bool spapr_ov5_cas_needed(void *opaque)
>>   {
>>       sPAPRMachineState *spapr = opaque;
>> @@ -1535,6 +1567,7 @@ static const VMStateDescription vmstate_spapr = {
>>       .subsections = (const VMStateDescription*[]) {
>>           &vmstate_spapr_ov5_cas,
>>           &vmstate_spapr_patb_entry,
>> +        &vmstate_spapr_pending_events,
>>           NULL
>>       }
>>   };
>> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
>> index f0b28d8..70c7cfc 100644
>> --- a/hw/ppc/spapr_events.c
>> +++ b/hw/ppc/spapr_events.c
>> @@ -342,7 +342,8 @@ static int rtas_event_log_to_irq(sPAPRMachineState *spapr, int log_type)
>>       return source->irq;
>>   }
>>   
>> -static void rtas_event_log_queue(int log_type, void *data, bool exception)
>> +static void rtas_event_log_queue(int log_type, void *data, bool exception,
>   +                                 int data_size)
>
> This could derive data_size from the header passed in.
>
>>   {
>>       sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
>>       sPAPREventLogEntry *entry = g_new(sPAPREventLogEntry, 1);
>> @@ -351,6 +352,7 @@ static void rtas_event_log_queue(int log_type, void *data, bool exception)
>>       entry->log_type = log_type;
>>       entry->exception = exception;
>>       entry->data = data;
>> +    entry->data_size = data_size;
>>       QTAILQ_INSERT_TAIL(&spapr->pending_events, entry, next);
>>   }
>>   
>> @@ -445,6 +447,7 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
>>       struct rtas_event_log_v6_mainb *mainb;
>>       struct rtas_event_log_v6_epow *epow;
>>       struct epow_log_full *new_epow;
>> +    uint32_t data_size;
>>   
>>       new_epow = g_malloc0(sizeof(*new_epow));
>>       hdr = &new_epow->hdr;
>> @@ -453,14 +456,13 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
>>       mainb = &new_epow->mainb;
>>       epow = &new_epow->epow;
>>   
>> +    data_size = sizeof(*new_epow);
>>       hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
>>                                  | RTAS_LOG_SEVERITY_EVENT
>>                                  | RTAS_LOG_DISPOSITION_NOT_RECOVERED
>>                                  | RTAS_LOG_OPTIONAL_PART_PRESENT
>>                                  | RTAS_LOG_TYPE_EPOW);
>> -    hdr->extended_length = cpu_to_be32(sizeof(*new_epow)
>> -                                       - sizeof(new_epow->hdr));
>> -
>> +    hdr->extended_length = cpu_to_be32(data_size - sizeof(new_epow->hdr));
>>       spapr_init_v6hdr(v6hdr);
>>       spapr_init_maina(maina, 3 /* Main-A, Main-B and EPOW */);
>>   
>> @@ -479,7 +481,7 @@ static void spapr_powerdown_req(Notifier *n, void *opaque)
>>       epow->event_modifier = RTAS_LOG_V6_EPOW_MODIFIER_NORMAL;
>>       epow->extended_modifier = RTAS_LOG_V6_EPOW_XMODIFIER_PARTITION_SPECIFIC;
>>   
>> -    rtas_event_log_queue(RTAS_LOG_TYPE_EPOW, new_epow, true);
>> +    rtas_event_log_queue(RTAS_LOG_TYPE_EPOW, new_epow, true, data_size);
>>   
>>       qemu_irq_pulse(xics_get_qirq(XICS_FABRIC(spapr),
>>                                    rtas_event_log_to_irq(spapr,
>> @@ -504,6 +506,7 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
>>       struct rtas_event_log_v6_maina *maina;
>>       struct rtas_event_log_v6_mainb *mainb;
>>       struct rtas_event_log_v6_hp *hp;
>> +    uint32_t data_size;
>>   
>>       new_hp = g_malloc0(sizeof(struct hp_log_full));
>>       hdr = &new_hp->hdr;
>> @@ -512,14 +515,14 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
>>       mainb = &new_hp->mainb;
>>       hp = &new_hp->hp;
>>   
>> +    data_size = sizeof(*new_hp);
>>       hdr->summary = cpu_to_be32(RTAS_LOG_VERSION_6
>>                                  | RTAS_LOG_SEVERITY_EVENT
>>                                  | RTAS_LOG_DISPOSITION_NOT_RECOVERED
>>                                  | RTAS_LOG_OPTIONAL_PART_PRESENT
>>                                  | RTAS_LOG_INITIATOR_HOTPLUG
>>                                  | RTAS_LOG_TYPE_HOTPLUG);
>> -    hdr->extended_length = cpu_to_be32(sizeof(*new_hp)
>> -                                       - sizeof(new_hp->hdr));
>> +    hdr->extended_length = cpu_to_be32(data_size - sizeof(new_hp->hdr));
>>   
>>       spapr_init_v6hdr(v6hdr);
>>       spapr_init_maina(maina, 3 /* Main-A, Main-B, HP */);
>> @@ -572,7 +575,7 @@ static void spapr_hotplug_req_event(uint8_t hp_id, uint8_t hp_action,
>>               cpu_to_be32(drc_id->count_indexed.index);
>>       }
>>   
>> -    rtas_event_log_queue(RTAS_LOG_TYPE_HOTPLUG, new_hp, true);
>> +    rtas_event_log_queue(RTAS_LOG_TYPE_HOTPLUG, new_hp, true, data_size);
>>   
>>       qemu_irq_pulse(xics_get_qirq(XICS_FABRIC(spapr),
>>                                    rtas_event_log_to_irq(spapr,
>> @@ -671,8 +674,7 @@ static void check_exception(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>>       if (!event) {
>>           goto out_no_events;
>>       }
>> -
>> -    hdr = event->data;
>> +    hdr = (struct rtas_error_log *)event->data;
>>       event_len = be32_to_cpu(hdr->extended_length) + sizeof(*hdr);
>>   
>>       if (event_len < len) {
>> @@ -728,7 +730,7 @@ static void event_scan(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>>           goto out_no_events;
>>       }
>>   
>> -    hdr = event->data;
>> +    hdr = (struct rtas_error_log *)event->data;
>>       event_len = be32_to_cpu(hdr->extended_length) + sizeof(*hdr);
>>   
>>       if (event_len < len) {
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index 5802f88..fbe1d93 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -599,7 +599,8 @@ sPAPRTCETable *spapr_tce_find_by_liobn(target_ulong liobn);
>>   struct sPAPREventLogEntry {
>>       int log_type;
>>       bool exception;
>> -    void *data;
>> +    uint8_t *data;
>> +    uint32_t data_size;
>>       QTAILQ_ENTRY(sPAPREventLogEntry) next;
>>   };
>>