>> > I see a couple of possible solutions: > 1. Do what Avi said. Make KVM_IRQ_LINE_STATUS be synchronous. Cons: > current QEMU uses KVM_IRQ_LINE_STATUS always and it means that it > will be slow on newer kernels You could backport the qemu change, verify that it builds, and push it to stable branches. It's hardly ideal but if nothing else comes up then it's a solution. > 2. Make KVM_IRQ_LINE_STATUS report coalescing only when vcpu is not > running during injection. This assumes that if vcpu is running and does > not process interrupt it is guest fault and the same can happen on real > HW too. Coalescing when vcpu is not running though is the result of CPU > overcommit and should be reported. Cons interface definition is kind of > murky. You still have a window where the vcpu is scheduled out with guest interrupts disabled, then scheduled back in and before it manages to handle the interrupt, the second one hits. It's worth testing though. > 3. Do not report KVM_IRQ_LINE_STATUS capability and move RTC to use EOI > notifiers for interrupt reinjection. This requires us to add interface > for reporting EOI to userspace. This is not in the scope of this > patchset. Cons: need to introduce new interface (and the one that will > not work on AMD BTW) > > Other ideas? 1. inject RTC interrupt 2. not see EOI 3. inject RTC interrupt 4. due to 2, report coalesced AMD can still use IRR test-and-set. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
