Re: [Qemu-devel] [PATCH] Fix backcompat for hotplug of SCSI controllers

[Anthony Liguori <anthony@codemonkey.ws>]

Daniel P. Berrange wrote:
> SCSI controllers have no trouble existing without any attached
> disks. This could be achieved with the (legacy) monitor syntax
>
>   pci_add pci_addr=auto storage if=scsi
>
> This is now denied with
>
>   scsi requires a backing file/device.
>   failed to add if=scsi
>
> There is no need for this denial and it breaks compatability
> with existing QEMU usage, so remove the check for presence
> of a drive.
>   

Gerd, care to comment?  This bit of code seems pretty intentional:

commit 5b684b5a56e81f6f88234952fe8ed68010c36e19
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Tue Oct 13 13:59:55 2009 +0200

    hotplug: fix "pci_add storage if=scsi"

>   Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  hw/pci-hotplug.c |    6 +-----
>  1 files changed, 1 insertions(+), 5 deletions(-)
>
> diff --git a/hw/pci-hotplug.c b/hw/pci-hotplug.c
> index 081d6d1..616435a 100644
> --- a/hw/pci-hotplug.c
> +++ b/hw/pci-hotplug.c
> @@ -182,14 +182,10 @@ static PCIDevice *qemu_pci_hot_add_storage(Monitor *mon,
>  
>      switch (type) {
>      case IF_SCSI:
> -        if (!dinfo) {
> -            monitor_printf(mon, "scsi requires a backing file/device.\n");
> -            return NULL;
> -        }
>          dev = pci_create(bus, devfn, "lsi53c895a");
>          if (qdev_init(&dev->qdev) < 0)
>              dev = NULL;
> -        if (dev) {
> +        if (dev && dinfo) {
>              if (scsi_hot_add(&dev->qdev, dinfo, 0) != 0) {
>                  qdev_unplug(&dev->qdev);
>                  dev = NULL;
>   


Regards,

Anthony Liguori