On Tue, 26 Jul 2016, Auger Eric wrote: > On 26/07/2016 11:00, Thomas Gleixner wrote: > > In your case you don't want to have a partial allocation, so instead of > > playing silly games with desc->irq you should add a flag which tells the PCI > > code that you are not interested in a partial allocation and that it should > > return an error code instead. > > In that case can we consider we even succeeded in allocating 1 MSI? In case > the IOMMU mapping fails, the MSI transaction will never reach the target MSI > frame so it is not usable. So when you mean "partial" I understand we did > not succeed in allocating maxvec IRQs, correct? Here we succeeded in > allocating 0 IRQ and still msi_capability_init returns 1. > > msi_capability_init doc-comment says "a positive return value indicates the > number of interrupts which could have been allocated." > > I understand allocation success currently only depends on the fact virq was > allocated and set to desc->irq. But with that IOMMU stuff doesn't the > criteria changes? Right. But then you need to express it differently in a consistent way. Not by hacking around it by setting desc->irq to 0. Something like a flag field in msi_desc which denotes various properties would be a possible solution. MSI_IRQ_ALLOCATED and MSI_IRQ_REMAPPED would be sufficient for now. And the deallocation/cleanup would rely on those flags rather than checking desc->irq. Thanks, tglx _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
