xen_platform: unplug also SCSI disks

Using 'vdev=sd[a-o]' will create an emulated LSI controller, which can
be used by the emulated BIOS to boot from disk. If the HVM domU has also
PV driver the disk may appear twice in the guest. To avoid this an
unplug of the emulated hardware is needed, similar to what is done for
IDE and NIC drivers already.

Since the SCSI controller provides only disks the entire controller can
be unplugged at once.

Impact of the change for classic and pvops based guest kernels:

 vdev=sda:disk0
before: pvops:   disk0=pv xvda + emulated sda
        classic: disk0=pv sda  + emulated sdq
after:  pvops:   disk0=pv xvda
        classic: disk0=pv sda

 vdev=hda:disk0, vdev=sda:disk1
before: pvops:   disk0=pv xvda
                 disk1=emulated sda
        classic: disk0=pv hda
                 disk1=pv sda  + emulated sdq
after:  pvops:   disk0=pv xvda
                 disk1=not accessible by blkfront, index hda==index sda
        classic: disk0=pv hda
                 disk1=pv sda

 vdev=hda:disk0, vdev=sda:disk1, vdev=sdb:disk2
before: pvops:   disk0=pv xvda
                 disk1=emulated sda
                 disk2=pv xvdb + emulated sdb
        classic: disk0=pv hda
                 disk1=pv sda  + emulated sdq
                 disk2=pv sdb  + emulated sdr
after:  pvops:   disk0=pv xvda
                 disk1=not accessible by blkfront, index hda==index sda
                 disk2=pv xvdb
        classic: disk0=pv hda
                 disk1=pv sda
                 disk2=pv sda

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index f85635cc9a45c999221a22b6c8df46c591b46790..91d8a7a2f07ab671079a845354f82a8bd37d7ce4 100644 (file)
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -114,6 +114,10 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *o)
             PCI_CLASS_STORAGE_IDE
             && strcmp(d->name, "xen-pci-passthrough") != 0) {
         pci_piix3_xen_ide_unplug(DEVICE(d));
+    } else if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
+            PCI_CLASS_STORAGE_SCSI
+            && strcmp(d->name, "xen-pci-passthrough") != 0) {
+        object_unparent(OBJECT(d));
     }
 }