On Fri, 21 Aug 2015 16:03:52 +0800
Jason Wang <jasowang@xxxxxxxxxx> wrote:
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 9ff4193..834a409 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -838,11 +838,6 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
>
> kvm_iodevice_init(&p->dev, &ioeventfd_ops);
>
> - ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
> - &p->dev);
> - if (ret < 0)
> - goto unlock_fail;
> -
> /* When length is ignored, MMIO is also put on a separate bus, for
> * faster lookups.
You probably want to change this comment as well?
> */
> @@ -850,9 +845,15 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
Unfortunately snipped by diff, but the check here is on !len && !PIO,
which only does the desired thing as VIRTIO_CCW always uses len == 8.
Should the check be for !len && MMIO instead?
> ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS,
> p->addr, 0, &p->dev);
> if (ret < 0)
> - goto register_fail;
> + goto unlock_fail;
> + } else {
> + ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
> + &p->dev);
> + if (ret < 0)
> + goto unlock_fail;
> }
Hm... maybe the following would be more obvious:
my_bus = (p->length == 0) && (bus_idx == KVM_MMIO_BUS) ? KVM_FAST_MMIO_BUS : bus_idx;
ret = kvm_io_bus_register_dev(kvm, my_bus, p->addr, p->length, &pdev->dev);
>
> +
> kvm->buses[bus_idx]->ioeventfd_count++;
> list_add_tail(&p->list, &kvm->ioeventfds);
(...)
> @@ -900,10 +899,11 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
> if (!p->wildcard && p->datamatch != args->datamatch)
> continue;
>
> - kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
> if (!p->length) {
> kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS,
> &p->dev);
> + } else {
> + kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
> }
Similar comments here... do you want to check for bus_idx ==
KVM_MMIO_BUS as well?
> kvm->buses[bus_idx]->ioeventfd_count--;
> ioeventfd_release(p);
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