Re: [qemu-s390x] [PATCH 01/15] s390 vfio-ccw: Add bootindex property and IPLB data

[Cornelia Huck]

On Tue, 29 Jan 2019 08:29:08 -0500
"Jason J. Herne" <address@hidden> wrote:

> Add bootindex property and iplb data for vfio-ccw devices. This allows us to
> forward boot information into the bios for vfio-ccw devices.
> 
> Signed-off-by: Jason J. Herne <address@hidden>
> Acked-by: Halil Pasic <address@hidden>
> ---
>  hw/s390x/ipl.c              | 14 ++++++++++++++
>  hw/s390x/s390-ccw.c         |  9 +++++++++
>  hw/vfio/ccw.c               | 13 +------------
>  include/hw/s390x/s390-ccw.h |  1 +
>  include/hw/s390x/vfio-ccw.h | 38 ++++++++++++++++++++++++++++++++++++++
>  5 files changed, 63 insertions(+), 12 deletions(-)
>  create mode 100644 include/hw/s390x/vfio-ccw.h
> 
> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
> index 21f64ad..a993f65 100644
> --- a/hw/s390x/ipl.c
> +++ b/hw/s390x/ipl.c
> @@ -19,6 +19,7 @@
>  #include "hw/loader.h"
>  #include "hw/boards.h"
>  #include "hw/s390x/virtio-ccw.h"
> +#include "hw/s390x/vfio-ccw.h"
>  #include "hw/s390x/css.h"
>  #include "hw/s390x/ebcdic.h"
>  #include "ipl.h"
> @@ -311,8 +312,12 @@ static CcwDevice *s390_get_ccw_device(DeviceState 
> *dev_st)
>          VirtioCcwDevice *virtio_ccw_dev = (VirtioCcwDevice *)
>              object_dynamic_cast(OBJECT(qdev_get_parent_bus(dev_st)->parent),
>                                  TYPE_VIRTIO_CCW_DEVICE);
> +        VFIOCCWDevice *vfio_ccw_dev = (VFIOCCWDevice *)
> +            object_dynamic_cast(OBJECT(dev_st), TYPE_VFIO_CCW);
>          if (virtio_ccw_dev) {
>              ccw_dev = CCW_DEVICE(virtio_ccw_dev);
> +        } else if (vfio_ccw_dev) {
> +            ccw_dev = CCW_DEVICE(vfio_ccw_dev);
>          } else {
>              SCSIDevice *sd = (SCSIDevice *)
>                  object_dynamic_cast(OBJECT(dev_st),
> @@ -347,6 +352,8 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
>      if (ccw_dev) {
>          SCSIDevice *sd = (SCSIDevice *) object_dynamic_cast(OBJECT(dev_st),
>                                                              
> TYPE_SCSI_DEVICE);
> +        VFIOCCWDevice *vc = (VFIOCCWDevice *)
> +            object_dynamic_cast(OBJECT(dev_st), TYPE_VFIO_CCW);
>  
>          if (sd) {
>              ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
> @@ -358,6 +365,13 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
>              ipl->iplb.scsi.channel = cpu_to_be16(sd->channel);
>              ipl->iplb.scsi.devno = cpu_to_be16(ccw_dev->sch->devno);
>              ipl->iplb.scsi.ssid = ccw_dev->sch->ssid & 3;
> +        } else if (vc) {
> +            CcwDevice *ccw_dev = CCW_DEVICE(vc);
> +
> +            ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
> +            ipl->iplb.pbt = S390_IPL_TYPE_CCW;
> +            ipl->iplb.ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
> +            ipl->iplb.ccw.ssid = ccw_dev->sch->ssid & 3;
>          } else {
>              VirtIONet *vn = (VirtIONet *) object_dynamic_cast(OBJECT(dev_st),
>                                                                
> TYPE_VIRTIO_NET);

Hm, I think that this find-out-the-boot-type-and-set-up-the-right-thing
mechanism is getting a bit unwieldy. Basically, we

- call s390_get_ccw_device() to find out the device type via a bunch of
  casts and return a pointer to a CcwDevice if it's a supported type
- do a bunch of casts here *again* to find out what we have and fill
  out the iplb, while we really only need to do grab a non-CcwDevice
  for the scsi case

Should maybe s390_get_ccw_device() give us an ipl type in addition to
the pointer to the CcwDevice, so we can use a switch/case statement to
fill out the iplb here?