[libvirt] [PATCH 0/4] qemu_hotplug: Check for duplicate drive addresses

[Daniel Henrique Barboza]

On 4/11/19 11:34 AM, Michal Privoznik wrote:
> This is an alternative approach to:
>
> https://www.redhat.com/archives/libvir-list/2019-March/msg01111.html
>
> which caused regression to which a proposed fix is here:
>
> https://www.redhat.com/archives/libvir-list/2019-April/msg00756.html
>
> One of the selling points was that having this check in
> virDomainDefCompatibleDevice() will fix the problem across all drivers.
> Well, turns out, some drivers don't care (e.g. lxc) and some have a
> different workflow and thus don't need that check.

Just tested the patch series and it fixes the problem for SCSI disks, as
expected.

The major drawback of reverting that patch is that we lose the address
check not just for other drivers (that might not care much for that), but
also for the remaining device types other than SCSI disks.

Now, taking a quick look in the code I see that there are similar checks
being made in VDA, PCI and DIMM type devices (didn't check the remaining
devices). If there are address redundancy checks for all other devices, then
the patch can be reverted without loss.

It is worth mentioning that the first 2 patches can be applied regardless of
what it is decided to do about the address checking, since they are a 
straight
improvement in what already exists.


Thanks,


DHB


>
> Michal Prívozník (4):
>    conf: Expose virDomainSCSIDriveAddressIsUsed
>    qemuhotplugtest: Don't plug a SCSI disk at unit 7
>    qemu_hotplug: Check for duplicate drive addresses
>    Revert "domain_conf: check device address before attach"
>
>   src/conf/domain_conf.c                                | 11 +----------
>   src/conf/domain_conf.h                                |  4 ++++
>   src/libvirt_private.syms                              |  1 +
>   src/qemu/qemu_hotplug.c                               |  6 ++++++
>   tests/qemuhotplugtest.c                               |  2 +-
>   .../qemuhotplug-disk-scsi-2.xml                       |  2 +-
>   ...-base-without-scsi-controller-live+disk-scsi-2.xml |  4 ++--
>   7 files changed, 16 insertions(+), 14 deletions(-)
>