Re: [Qemu-devel] [RESEND PATCH] virtio-scsi: forward scsibus for virtio-scsi-pci.

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 12, 2013 at 09:21:41PM +1000, Alexey Kardashevskiy wrote:
> On 06/12/2013 07:16 PM, Michael S. Tsirkin wrote:
> > On Wed, Jun 12, 2013 at 07:04:48PM +1000, Alexey Kardashevskiy wrote:
> >> On 06/12/2013 07:03 PM, Michael S. Tsirkin wrote:
> >>> On Wed, Jun 12, 2013 at 08:15:17AM +0200, fred.konrad@greensocs.com wrote:
> >>>> From: KONRAD Frederic <fred.konrad@greensocs.com>
> >>>>
> >>>> This fix a bug with scsi hotplug on virtio-scsi-pci:
> >>>>
> >>>> As virtio-scsi-pci doesn't have any scsi bus, we need to forward scsi-hot-add
> >>>> to the virtio-scsi-device plugged on the virtio-bus.
> >>>>
> >>>> Cc: qemu-stable@nongnu.org
> >>>> Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> >>>> Reviewed-by: Andreas Färber <afaerber@suse.de>
> >>>> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
> >>>
> >>> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> >>>
> >>> Note: we don't seem to have any decent way to
> >>> add disks to devices: no QMP interface,
> >>> pci address is required instead of using an id ...
> >>>
> >>> Anyone can be bothered to fix this?
> >>
> >>
> >> Actually PCI address is not always required, this field (we are talking
> >> about "drive_add"?) is ignored when "if=none".
> >>
> > 
> > Then documentation in hmp-commands.hx is wrong, isn't it?
> > Add that to the list.
> > 
> > if=none can't be actually used to hot-add
> > a disk to a device, can it? It creates a disc and assumes you will
> > use it by a device created later.
> 
> 
> Yep. I run QEMU with -device "virtio-scsi-pci,id=device0" and then do in
> console:
> drive_add auto file=virtimg/fc18guest,if=none,id=bar1
> device_add scsi-disk,bus=device0.0,drive=bar1
> 
> Pretty hot plug :)

I see. So you pass the device id of a patent as a bus option?

So the real problem is that there's no documentation
and what is there in hmp-commands.hx, is wrong.

> 
> > 
> > 
> >>
> >>>> ---
> >>>>  hw/pci/pci-hotplug.c | 19 +++++++++++++++++--
> >>>>  1 file changed, 17 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/hw/pci/pci-hotplug.c b/hw/pci/pci-hotplug.c
> >>>> index 12287d1..c708752 100644
> >>>> --- a/hw/pci/pci-hotplug.c
> >>>> +++ b/hw/pci/pci-hotplug.c
> >>>> @@ -30,6 +30,8 @@
> >>>>  #include "monitor/monitor.h"
> >>>>  #include "hw/scsi/scsi.h"
> >>>>  #include "hw/virtio/virtio-blk.h"
> >>>> +#include "hw/virtio/virtio-scsi.h"
> >>>> +#include "hw/virtio/virtio-pci.h"
> >>>>  #include "qemu/config-file.h"
> >>>>  #include "sysemu/blockdev.h"
> >>>>  #include "qapi/error.h"
> >>>> @@ -79,13 +81,26 @@ static int scsi_hot_add(Monitor *mon, DeviceState *adapter,
> >>>>  {
> >>>>      SCSIBus *scsibus;
> >>>>      SCSIDevice *scsidev;
> >>>> +    VirtIOPCIProxy *virtio_proxy;
> >>>>  
> >>>>      scsibus = (SCSIBus *)
> >>>>          object_dynamic_cast(OBJECT(QLIST_FIRST(&adapter->child_bus)),
> >>>>                              TYPE_SCSI_BUS);
> >>>>      if (!scsibus) {
> >>>> -	error_report("Device is not a SCSI adapter");
> >>>> -	return -1;
> >>>> +        /*
> >>>> +         * Check if the adapter is a virtio-scsi-pci, and forward scsi_hot_add
> >>>> +         * to the virtio-scsi-device.
> >>>> +         */
> >>>> +        if (!object_dynamic_cast(OBJECT(adapter), TYPE_VIRTIO_SCSI_PCI)) {
> >>>> +            error_report("Device is not a SCSI adapter");
> >>>> +            return -1;
> >>>> +        }
> >>>> +        virtio_proxy = VIRTIO_PCI(adapter);
> >>>> +        adapter = DEVICE(virtio_proxy->bus.vdev);
> >>>> +        scsibus = (SCSIBus *)
> >>>> +                  object_dynamic_cast(OBJECT(QLIST_FIRST(&adapter->child_bus)),
> >>>> +                            TYPE_SCSI_BUS);
> >>>> +        assert(scsibus);
> >>>>      }
> >>>>  
> >>>>      /*
> 
> 
> -- 
> Alexey