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

[Michael S. Tsirkin]

On Tue, Jun 11, 2013 at 08:43:51AM +0200, Frederic Konrad wrote:
> On 10/06/2013 19:00, Michael S. Tsirkin wrote:
> >On Mon, Jun 10, 2013 at 11:53:04AM +0200, address@hidden wrote:
> >>From: KONRAD Frederic <address@hidden>
> >>
> >>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.
> >>
> >>Reported-by: Alexey Kardashevskiy <address@hidden>
> >>Signed-off-by: KONRAD Frederic <address@hidden>
> >>---
> >>  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);
> >>      }
> >>      /*
> >By the way I really wonder. pci-hotplug.c was supposed to
> >be legacy interface.
> >Is this the only way to add scsi disks?
> >And are other ways broken, too?
> 
> Here you can add scsi disks to a given device.
> I think the other ways add scsi disks to a given bus?
> 
> Do you see any other?
> 
> Thanks,
> Fred

I don't know, that's why I'm asking.

If it is, that's crazy. There's no reason for
it to be tied to pci at all.

The commands in pci-hotplug.c are legacy - they don't support things
like multi root systems and there's no sane way to make them do it.

Your patch probably makes sense for stable, but for 1.6,
let's fix this properly.

> >
> >>-- 
> >>1.8.1.4