2016-08-29 17:55 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: > > > On 25/08/2016 11:12, Wanpeng Li wrote: >>> > >>> > ioctl when? interrupt kind >>> > ------------------------------------------------------------------------ >>> > KVM_INTERRUPT i8259 in userspace EXTINT >>> > KVM_SET_GSI_ROUTING (always) IOAPIC >>> > KVM_SIGNAL_MSI (always) MSI >>> > KVM_SET_GSI_ROUTING (always) MSI >>> > KVM_IRQFD any that can use KVM_SET_GSI_ROUTING >>> > >>> > After KVM_SET_GSI_ROUTING, the host invokes another ioctl on the VM >> MSI routing is also set by KVM_SET_GSI_ROUTING，though MSI/MSI-X >> doesn't associated with GSI, this is intended to save a KVM API, >> right? In addition, kvm_send_userspace_msi() which is called in >> KVM_SIGNAL_MSI path set MSI routing entry again, > > No, kvm_send_userspace_msi simply converts the struct used by userspace > (struct kvm_msi) into the one used by the kernel (struct > kvm_kernel_irq_routing_entry). Agreed. :) > > I saw there are >> patches which will update gsi routing after changed MSI-X >> configuration(https://patchwork.kernel.org/patch/6827431/) >> , so why set MSI routing entry again during send MSI? > > KVM_SIGNAL_MSI does not need a previous KVM_SET_GSI_ROUTING, but if > userspace wants it can use both. Note that you've linked a patch for > lkvm, not Linux or QEMU. Do you mean that MSI/MSI-X don't necessary have a routing table? Regards, Wanpeng Li -- 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
