Re: [Qemu-devel] [PATCH 1/1] s390x: vmstatify config migration for virtio-ccw

[Christian Borntraeger]

On 06/01/2017 01:02 PM, Halil Pasic wrote:
> 
> 
> On 06/01/2017 12:52 PM, Cornelia Huck wrote:
>> On Mon, 29 May 2017 15:17:16 +0200
>> Halil Pasic <address@hidden> wrote:
>>
>>> Let's vmstatify virtio_ccw_save_config and virtio_ccw_load_config for
>>> flexibility (extending using subsections) and for fun.
>>
>> You have interesting ideas of fun :)
>>
>>>
>>> To achieve this we need to hack the config_vector, which is VirtIODevice
>>> (that is common virtio) state, in the middle of the VirtioCcwDevice state
>>> representation.  This somewhat ugly, but we have no choice because the
>>> stream format needs to be preserved.
>>>
>>> Almost no changes in behavior. Exception is everything that comes with
>>> vmstate like extra bookkeeping about what's in the stream, and maybe some
>>> extra checks and better error reporting.
>>>
>>> Signed-off-by: Halil Pasic <address@hidden>
>>> ---
> [..]
>>> --- a/hw/s390x/css.c
>>> +++ b/hw/s390x/css.c
> [..]
>>> +static const VMStateDescription vmstate_sense_id = {
>>> +    .name = "s390_sense_id",
>>> +    .version_id = 1,
>>> +    .minimum_version_id = 1,
>>> +    .fields = (VMStateField[]) {
>>> +        VMSTATE_UINT8(reserved, SenseId),
>>> +        VMSTATE_UINT16(cu_type, SenseId),
>>> +        VMSTATE_UINT8(cu_model, SenseId),
>>> +        VMSTATE_UINT16(dev_type, SenseId),
>>> +        VMSTATE_UINT8(dev_model, SenseId),
>>> +        VMSTATE_UINT8(unused, SenseId),
>>
>> This is strictly due to stream format preservation, right?
>>
> 
> Yes!
> 
> [..]
>>> --- a/hw/s390x/virtio-ccw.c
>>> +++ b/hw/s390x/virtio-ccw.c
>>> @@ -34,9 +34,87 @@
>>>  #include "virtio-ccw.h"
>>>  #include "trace.h"
>>>  #include "hw/s390x/css-bridge.h"
>>> +#include "hw/s390x/s390-virtio-ccw.h"
>>>
>>>  #define NR_CLASSIC_INDICATOR_BITS 64
>>>
>>> +static int virtio_ccw_dev_post_load(void *opaque, int version_id)
>>> +{
>>> +    VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(opaque);
>>> +    CcwDevice *ccw_dev = CCW_DEVICE(dev);
>>> +    CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
>>> +
>>> +    ccw_dev->sch->driver_data = dev;
>>> +    if (CCW_DEVICE(dev)->sch->thinint_active) {
>>
>> Please use ccw_dev instead of CCW_DEVICE(dev).
>>
> 
> Sure.
> 
>>> +        dev->routes.adapter.adapter_id = css_get_adapter_id(
>>> +                                         CSS_IO_ADAPTER_VIRTIO,
>>> +                                         dev->thinint_isc);
>>> +    }
>>> +    /* Re-fill subch_id after loading the subchannel states.*/
>>> +    if (ck->refill_ids) {
>>> +        ck->refill_ids(ccw_dev);
>>> +    }
>>> +    return 0;
>>> +}
>>> +
>>> +typedef struct VirtioCcwDeviceTmp {
>>> +    VirtioCcwDevice *parent;
>>> +    uint16_t config_vector;
>>> +} VirtioCcwDeviceTmp;
>>> +
>>> +static void virtio_ccw_dev_tmp_pre_save(void *opaque)
>>> +{
>>> +    VirtioCcwDeviceTmp *tmp = opaque;
>>> +    VirtioCcwDevice *dev = tmp->parent;
>>> +    VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
>>> +
>>> +    tmp->config_vector = vdev->config_vector;
>>> +}
>>> +
>>> +static int virtio_ccw_dev_tmp_post_load(void *opaque, int version_id)
>>> +{
>>> +    VirtioCcwDeviceTmp *tmp = opaque;
>>> +    VirtioCcwDevice *dev = tmp->parent;
>>> +    VirtIODevice *vdev = virtio_bus_get_device(&dev->bus);
>>> +
>>> +    vdev->config_vector = tmp->config_vector;
>>> +    return 0;
>>> +}
>>> +
>>> +const VMStateDescription vmstate_virtio_ccw_dev_tmp = {
>>> +    .name = "s390_virtio_ccw_dev_tmp",
>>> +    .pre_save = virtio_ccw_dev_tmp_pre_save,
>>> +    .post_load = virtio_ccw_dev_tmp_post_load,
>>> +    .fields = (VMStateField[]) {
>>> +        VMSTATE_UINT16(config_vector, VirtioCcwDeviceTmp),
>>> +        VMSTATE_END_OF_LIST()
>>> +    }
>>> +};
>>> +
>>> +const VMStateDescription vmstate_virtio_ccw_dev = {
>>> +    .name = "s390_virtio_ccw_dev",
>>> +    .version_id = 1,
>>> +    .minimum_version_id = 1,
>>> +    .post_load = virtio_ccw_dev_post_load,
>>> +    .fields = (VMStateField[]) {
>>> +        VMSTATE_CCW_DEVICE(parent_obj, VirtioCcwDevice),
>>> +        VMSTATE_PTR_TO_IND_ADDR(indicators, VirtioCcwDevice),
>>> +        VMSTATE_PTR_TO_IND_ADDR(indicators2, VirtioCcwDevice),
>>> +        VMSTATE_PTR_TO_IND_ADDR(summary_indicator, VirtioCcwDevice),
>>> +        /*
>>> +         * Ugly hack because VirtIODevice does not migrate itself.
>>> +         * This also makes legacy via vmstate_save_state possible.
>>> +         */
>>> +        VMSTATE_WITH_TMP(VirtioCcwDevice, VirtioCcwDeviceTmp,
>>> +                         vmstate_virtio_ccw_dev_tmp),
>>> +        VMSTATE_STRUCT(routes, VirtioCcwDevice, 1, vmstate_adapter_routes, 
>>> \
>>> +                       AdapterRoutes),
>>> +        VMSTATE_UINT8(thinint_isc, VirtioCcwDevice),
>>> +        VMSTATE_INT32(revision, VirtioCcwDevice),
>>> +        VMSTATE_END_OF_LIST()
>>> +    }
>>> +};
>>> +
>>>  static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
>>>                                 VirtioCcwDevice *dev);
>>>
>>> @@ -1234,85 +1312,13 @@ static int virtio_ccw_load_queue(DeviceState *d, 
>>> int n, QEMUFile *f)
>>>  static void virtio_ccw_save_config(DeviceState *d, QEMUFile *f)
>>>  {
>>>      VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
>>> -    CcwDevice *ccw_dev = CCW_DEVICE(d);
>>> -    SubchDev *s = ccw_dev->sch;
>>> -    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
>>> -
>>> -    subch_device_save(s, f);
>>> -    if (dev->indicators != NULL) {
>>> -        qemu_put_be32(f, dev->indicators->len);
>>> -        qemu_put_be64(f, dev->indicators->addr);
>>> -    } else {
>>> -        qemu_put_be32(f, 0);
>>> -        qemu_put_be64(f, 0UL);
>>> -    }
>>> -    if (dev->indicators2 != NULL) {
>>> -        qemu_put_be32(f, dev->indicators2->len);
>>> -        qemu_put_be64(f, dev->indicators2->addr);
>>> -    } else {
>>> -        qemu_put_be32(f, 0);
>>> -        qemu_put_be64(f, 0UL);
>>> -    }
>>> -    if (dev->summary_indicator != NULL) {
>>> -        qemu_put_be32(f, dev->summary_indicator->len);
>>> -        qemu_put_be64(f, dev->summary_indicator->addr);
>>> -    } else {
>>> -        qemu_put_be32(f, 0);
>>> -        qemu_put_be64(f, 0UL);
>>> -    }
>>> -    qemu_put_be16(f, vdev->config_vector);
>>> -    qemu_put_be64(f, dev->routes.adapter.ind_offset);
>>> -    qemu_put_byte(f, dev->thinint_isc);
>>> -    qemu_put_be32(f, dev->revision);
>>> +    vmstate_save_state(f, &vmstate_virtio_ccw_dev, dev, NULL);
>>>  }
>>>
>>>  static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
>>>  {
>>>      VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
>>> -    CcwDevice *ccw_dev = CCW_DEVICE(d);
>>> -    CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
>>> -    SubchDev *s = ccw_dev->sch;
>>> -    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
>>> -    int len;
>>> -
>>> -    s->driver_data = dev;
>>> -    subch_device_load(s, f);
>>> -    /* Re-fill subch_id after loading the subchannel states.*/
>>> -    if (ck->refill_ids) {
>>> -        ck->refill_ids(ccw_dev);
>>> -    }
>>> -    len = qemu_get_be32(f);
>>> -    if (len != 0) {
>>> -        dev->indicators = get_indicator(qemu_get_be64(f), len);
>>> -    } else {
>>> -        qemu_get_be64(f);
>>> -        dev->indicators = NULL;
>>> -    }
>>> -    len = qemu_get_be32(f);
>>> -    if (len != 0) {
>>> -        dev->indicators2 = get_indicator(qemu_get_be64(f), len);
>>> -    } else {
>>> -        qemu_get_be64(f);
>>> -        dev->indicators2 = NULL;
>>> -    }
>>> -    len = qemu_get_be32(f);
>>> -    if (len != 0) {
>>> -        dev->summary_indicator = get_indicator(qemu_get_be64(f), len);
>>> -    } else {
>>> -        qemu_get_be64(f);
>>> -        dev->summary_indicator = NULL;
>>> -    }
>>> -    qemu_get_be16s(f, &vdev->config_vector);
>>> -    dev->routes.adapter.ind_offset = qemu_get_be64(f);
>>> -    dev->thinint_isc = qemu_get_byte(f);
>>> -    dev->revision = qemu_get_be32(f);
>>> -    if (s->thinint_active) {
>>> -        dev->routes.adapter.adapter_id = css_get_adapter_id(
>>> -                                         CSS_IO_ADAPTER_VIRTIO,
>>> -                                         dev->thinint_isc);
>>> -    }
>>> -
>>> -    return 0;
>>> +    return vmstate_load_state(f, &vmstate_virtio_ccw_dev, dev, 1);
>>>  }
>>>
>>>  static void virtio_ccw_pre_plugged(DeviceState *d, Error **errp)
>>> diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
>>> index e61fa74d9b..d74e44d312 100644
>>> --- a/include/hw/s390x/css.h
>>> +++ b/include/hw/s390x/css.h
>>> @@ -88,6 +88,7 @@ struct SubchDev {
>>>      bool ccw_fmt_1;
>>>      bool thinint_active;
>>>      uint8_t ccw_no_data_cnt;
>>> +    uint16_t migrated_schid; /* used for missmatch detection */
>>>      /* transport-provided data: */
>>>      int (*ccw_cb) (SubchDev *, CCW1);
>>>      void (*disable_cb)(SubchDev *);
>>> @@ -95,22 +96,27 @@ struct SubchDev {
>>>      void *driver_data;
>>>  };
>>>
>>> +extern const VMStateDescription vmstate_subch_dev;
>>> +
>>>  typedef struct IndAddr {
>>>      hwaddr addr;
>>>      uint64_t map;
>>>      unsigned long refcnt;
>>> -    int len;
>>> +    int32_t len;
>>>      QTAILQ_ENTRY(IndAddr) sibling;
>>>  } IndAddr;
>>>
>>> +extern const VMStateDescription vmstate_ind_addr;
>>> +
>>> +#define VMSTATE_PTR_TO_IND_ADDR(_f, _s)                                   \
>>> +    VMSTATE_STRUCT(_f, _s, 1, vmstate_ind_addr, IndAddr*)
>>> +
>>>  IndAddr *get_indicator(hwaddr ind_addr, int len);
>>>  void release_indicator(AdapterInfo *adapter, IndAddr *indicator);
>>>  int map_indicator(AdapterInfo *adapter, IndAddr *indicator);
>>>
>>>  typedef SubchDev *(*css_subch_cb_func)(uint8_t m, uint8_t cssid, uint8_t 
>>> ssid,
>>>                                         uint16_t schid);
>>> -void subch_device_save(SubchDev *s, QEMUFile *f);
>>> -int subch_device_load(SubchDev *s, QEMUFile *f);
>>>  int css_create_css_image(uint8_t cssid, bool default_image);
>>>  bool css_devno_used(uint8_t cssid, uint8_t ssid, uint16_t devno);
>>>  void css_subch_assign(uint8_t cssid, uint8_t ssid, uint16_t schid,
>>> diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h
>>> index f9e6890c90..caa6fc608d 100644
>>> --- a/include/hw/s390x/s390_flic.h
>>> +++ b/include/hw/s390x/s390_flic.h
>>> @@ -31,6 +31,11 @@ typedef struct AdapterRoutes {
>>>      int gsi[ADAPTER_ROUTES_MAX_GSI];
>>>  } AdapterRoutes;
>>>
>>> +extern const VMStateDescription vmstate_adapter_routes;
>>> +
>>> +#define VMSTATE_ADAPTER_ROUTES(_f, _s) \
>>> +    VMSTATE_STRUCT(_f, _s, 1, vmstate_adapter_routes, AdapterRoutes)
>>> +
>>>  #define TYPE_S390_FLIC_COMMON "s390-flic"
>>>  #define S390_FLIC_COMMON(obj) \
>>>      OBJECT_CHECK(S390FLICState, (obj), TYPE_S390_FLIC_COMMON)
>>
>> Other than the nit above, looks good to me. Especially the migration of
>> the pmcw & co. is now more readable. So, with the nit fixed,
>>
>> Reviewed-by: Cornelia Huck <address@hidden>
> 
> Thanks!
> 
>>
>> Christian, can you please take this?
>>
> 
> Should I do a re-spin with the nit's picked and the r-b's added?

Yes please. Can you then give me a confirmation that you have tested a 
migration between 2.9 and this patch set?