Re: [libvirt] [PATCH 0/4] qemu_hotplug: Check for duplicate drive addresses
On 4/11/19 8:36 PM, Daniel Henrique Barboza wrote:
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.
Yep, other types of addresees are covered. At least in drivers that do
care. LXC doesn't because it doesn't make much sense there. I mean, a
container shares HW with the host, so we can't really make it appear at
different addresses. For instance, when plugging a disk into an LXC
container it'll appear at the same adddess as in the host and no
<address/> in the XML is going to change that.
That's why I vouche for this approach. Sorry for not realizing this the
first time.
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,
Michal