On Fri, Jul 11, 2008 at 03:59:59PM -0700, Eric W. Biederman wrote: > Suresh Siddha <suresh.b.siddha@xxxxxxxxx> writes: > > > With interrupt-remapping, we can program the individual interrupt > > remapping table entries to point to different cpu's etc. All we have > > to take care is, do the IRTE allocation in a consecutive block and > > program the starting index to the MSI registers. > > > > Just curious Eric, why do you think that won't work? > > Working mask/unmask. With MSI-X as specced if I mask an irq and then unmask > it, an msi message will fire if something happened while the irq was masked > and not taken care of before the irq was unmasked. That is the correct > behavior for an irq and a mmu won't let me get that. And why do we need to mask/unmask the device in the interrupt-remapping case? > > The best I can do with an iommu is to run delayed disable and set the > interrupt remapping slot in the iommu to reject the traffic. Which > is almost but not quite what I want. > > Overall introducing a new concept into the linux irq model seems a lot > cleaner and more portable, and even there we are likely to be a lot > more fragile because of the difficulty in obtaining contiguous > vectors. > > Speaking of. How many interrupt targets does the dmar iommu have > for interrupts? 16K? There can be multiple interrupt-remapping units in the platform and each of table in the remapping unit has max 64K entries. thanks, suresh -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
