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

[Alexey Kardashevskiy <aik@ozlabs.ru>]

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 :)


> 
> 
>>
>>>> ---
>>>>  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