On Tue, Sep 27, 2022 at 04:47:20PM -0400, Michael S. Tsirkin wrote: > > The log : > > "genirq: Flags mismatch irq 0. 00000080 (virtio418) vs. 00015a00 (timer)" > > was print because of the irq 0 is used by timer exclusive,and when > > vp_find_vqs called vp_find_vqs_msix and return false twice,then it will > > call vp_find_vqs_intx for the last try. > > Because vp_dev->pci_dev->irq is zero,so it will be request irq 0 with > > flag IRQF_SHARED. > > First this is a bug. We can fix that so it will fail more cleanly. > > We should check pci_dev->pin and if 0 do not try to use INT#x > at all. > It will still fail, just with a nicer backtrace. How do we end up with a pci_dev without a valid PIN? Btw, that whole vp_find_* code looks extremely fucked up to me. The whole point of pci_alloc_irq_vectors* API is that it keeps drivers from poling into details of MSI-X v MSI vs INTX. > - because of auto affinity, we try to reserve an interrupt on all CPUs > - as there are 512 devices with a single vector per VQ we would > have no issue as they would be spread between CPUs, > but allocating on all CPUs fails. > > > I don't think the issue should be fixed at blk level - it is not > blk specifix - but yes this looks like a problem. > Christoph, any idea? I think this goes into the low-level interrupt vector allocator. I think Thomas is still the expert on it.
