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The subchannel is a means to access a device. While the device number is assigned by the administrator, the subchannel number is assigned by the channel subsystem in an ascending order on cold and hot plug. When doing unplug and replug operations, the same device may end up on a different subchannel; for example - We start with a device fe.1.2222, which ends up at subchannel fe.1.0000. - Now we detach the device, attach a device fe.1.3333 (which would get the now-free subchannel fe.1.0000), re-attach fe.1.2222 (which ends up at subchannel fe.1.0001) and detach fe.1.3333. - We now have the same device (fe.1.2222) available to the guest; it just shows up on a different subchannel. In such a case, the subchannel numbers are different from what a QEMU would create during cold plug when parsing the command line. As this would cause a guest visible change on migration, we do restore the source system's value of the subchannel number on load. So we are now fine from the guest perspective. From the host perspective this will cause an inconsistent state in our internal data structures, though. For example, the subchannel 0 might not be at array position 0. This will lead to problems when we continue doing hot (un/re) plug operations. Let's fix this by cleaning up our internal data structures. Reported-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Cc: qemu-stable@nongnu.org Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> |
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| .. | ||
| ccw-device.c | ||
| ccw-device.h | ||
| css-bridge.c | ||
| css.c | ||
| event-facility.c | ||
| ipl.c | ||
| ipl.h | ||
| Makefile.objs | ||
| s390-pci-bus.c | ||
| s390-pci-bus.h | ||
| s390-pci-inst.c | ||
| s390-pci-inst.h | ||
| s390-skeys-kvm.c | ||
| s390-skeys.c | ||
| s390-virtio-ccw.c | ||
| s390-virtio-hcall.c | ||
| s390-virtio.c | ||
| s390-virtio.h | ||
| sclp.c | ||
| sclpcpu.c | ||
| sclpquiesce.c | ||
| trace-events | ||
| virtio-ccw.c | ||
| virtio-ccw.h | ||