On Thu, 2017-06-29 at 20:03 +0200, Andrea Bolognani wrote:
This series is required to solve a known limitation in the current incarnation of device isolation support[1], namely the inability to isolate host devices coming from IOMMU group 0. The issue lies in the fact that virDomainDeviceInfo, and all virDomain*Def that embed it, are usually allocated through VIR_ALLOC(), which result in all their fields being initialized to zero. That's worked out just fine so far, because zero was a sensible default value for all existing fields; however, when implementing isolation groups, we add a new virDomainDeviceInfo::isolationGroup field which we need to be initialized to -1 instead so that it doesn't overlap with IOMMU group 0 mentioned above.
Or we could just, you know, do the sensible thing and store (IOMMU group + 1) instead of (IOMMU group) in virDomainDeviceInfo::isolationGroup and avoid the issue altogether? I'm actually quite embarassed I didn't think of that earlier :/
Solving the issue involves creating twenty or so virDomain*DefNew() functions and using them instead of VIR_ALLOC() every time a virDomain*Def needs to be created, which is arguably a pretty good idea regardless.
We could still merge this series, though, or at least parts of it. It improves upon some questionable code. -- Andrea Bolognani / Red Hat / Virtualization