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