Messages in this thread | | | Date | Fri, 19 Dec 2014 12:59:26 +0100 | From | Paolo Bonzini <> | Subject | Re: [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for VT-d PI |
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On 19/12/2014 02:30, Wu, Feng wrote: >>> How this can work well? All subsequent interrupts are delivered to >>> one vCPU? It shouldn't be the best solution, need more consideration. >> >> Well, it's a hardware limitation. The alternative (which is easy to >> implement) is to only do PI for single-CPU interrupts. This should work >> well for multiqueue NICs (and of course for UP guests :)), so perhaps >> it's a good idea to only support that as a first attempt. >> >> Paolo > > Paolo, what do you mean by "single-CPU interrupts"? Do you mean we don't > support lowest priority interrupts for PI? But Linux OS uses lowest priority > for most of the case? If so, we can hardly get benefit from this feature for > Linux guest OS.
You can post lowest priority interrupts if they are delivered to a single CPU, in which case they are effectively fixed priority.
If they are broadcast to multiple CPUs, do not post them.
Paolo
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