On Wed, 2020-10-07 at 16:05 +0200, Thomas Gleixner wrote: > On Wed, Oct 07 2020 at 14:08, David Woodhouse wrote: > > On 7 October 2020 13:59:00 BST, Thomas Gleixner wrote: > > > On Wed, Oct 07 2020 at 08:48, David Woodhouse wrote: > > > > To fix *that* case, we really do need the whole series giving us per- > > > > domain restricted affinity, and to use it for those MSIs/IOAPICs that > > > > the IRQ remapping doesn't cover. > > > > > > Which do not exist today. > > > > Sure. But at patch 10/13 into this particular patch series, it *does* > > exist. > > As I told you before: Your ordering is wrong. We do not introduce bugs > first and then fix them later .... I didn't introduce that bug; it's been there for years. Fixing it properly requires per-irqdomain affinity limits. There's a cute little TODO at least in the Intel irq-remapping driver, noting that we should probably check if there are any IOAPICs that aren't in the scope of any DRHD at all. But that's all. If it happens, I think we'll end up doing the right thing and instantiating a non-IR IOAPIC domain for it, and if we *don't* have any CPU with an APIC ID above... (checks notes)... 7 ... then it'll just about work out. Over 7 and we're screwed (because logical mode; see also https://git.infradead.org/users/dwmw2/linux.git/commit/429f0c33f for a straw man but that's getting even further down the rabbit hole)