Il 06/08/2014 16:03, Zhang, Yang Z ha scritto: > Paolo Bonzini wrote on 2014-07-31: >> Probably, the guest is masking the interrupt in the redirection table in >> the interrupt routine, i.e. while the interrupt is set in a LAPIC's ISR. >> The simplest fix is to ignore the masking state, we would rather have >> an unnecessary exit rather than a missed IRQ ACK and anyway IOAPIC >> interrupts are not as performance-sensitive as for example MSIs. > > I feel this fixing may hurt performance in some cases. If the mask > bit is set, this means the vector in this entry may be used by other > devices(like a assigned device). But here you set it in eoi exit bitmap > and this will cause vmexit on each EOI which should not happen. Note that this *was* reported on an assigned device. IOAPIC should not be a performance-sensitive path. High-performance assigned devices should be using MSIs. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
