2018-03-05 11:29+0100, Vitaly Kuznetsov: > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes: > > > Devices which use level-triggered interrupts under Windows 2016 with > > Hyper-V role enabled don't work: Windows disables EOI broadcast in SPIV > > unconditionally. Our in-kernel IOAPIC implementation emulates an old IOAPIC > > version which has no EOI register so EOI never happens. > > > > The issue was discovered and discussed a while ago: > > https://www.spinics.net/lists/kvm/msg148098.html > > > > Radim, Paolo, > > do we have a consensus here? (I wouldn't mind re-writing commit message > in case you think we shouldn't blame Windows, I just want to have the > annoying bug fixed :-) I have applied the patch, thanks. I think the commit message is correct (this is a Windows bug): * Current SDM has a different wording that only talks about EOI-broadcast suppression capability of the CPU. * The x2APIC document mentions that "the bit is reserved to 0 if the processor doesn't support Directed EOI" and IOAPIC is not a part of the processor, so I would assume that it doesn't hold. Basically, I think that the document confuses "Directed EOI" CPU feature and "directed EOI" IOAPIC feature, which got amended in SDM.
