[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] domU guest for xcp 0.1.1
On Thu, 2010-03-18 at 14:27 +0000, Ian Campbell wrote: > On Thu, 2010-03-18 at 14:23 +0000, Ritu kaur wrote: > > Thanks Ian, could you please clarify me how are interrupts handled > for > > pci passthrough device. I thought it is delivered via evtchn from > > pciback to pcifront i.e > > InterruptDescTable->Hypervisor->pciback->pcifront->actual_device is > > this correct? > > Yes, but not on the event channel you found previously, there is a > separate one for each device IRQ. Actually, not quite. pciback sets up an evtchn which pcifront binds to but pciback then arranges for the hypervisor to directly inject the interrupt on that event channel rather than bouncing through pciback for every interrupt so the actual path is more like: InterruptDescTable->Hypervisor->pcifront->actual_device And really once the device is setup pcifront isn't really involved either, the interrupt goes straight from the event channel to the device driver's interrupt handlerm pciback doesn't do anything for this part. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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