Re: [Qemu-devel] [PATCH] kvm: add KVM_IRQFD_FLAG_RESAMPLE support

[Alex Williamson]

On Mon, 2013-07-22 at 12:43 +0200, Vincenzo Maffione wrote:
> From e59e35380380c2986cd0164f11dcd8a07a8e4e59 Mon Sep 17 00:00:00 2001
> From: Vincenzo Maffione <address@hidden>
> Date: Mon, 22 Jul 2013 11:51:33 +0200
> Subject: [PATCH] kvm: add KVM_IRQFD_FLAG_RESAMPLE support
> 
> Added an EventNotifier* parameter to
> kvm-all.c:kvm_irqchip_add_irqfd_notifier(), in order to give KVM
> another eventfd to be used as "resamplefd". See the documentation
> in the linux kernel sources in Documentation/virtual/kvm/api.txt
> (section 4.75) for more details.
> When the added parameter is passed NULL, the behaviour of the
> function is unchanged with respect to the previous versions.
> 
> Signed-off-by: Vincenzo Maffione <address@hidden>
> ---
>  hw/misc/vfio.c         |  4 ++--
>  hw/virtio/virtio-pci.c |  2 +-
>  include/sysemu/kvm.h   |  3 ++-
>  kvm-all.c              | 17 +++++++++++++----
>  4 files changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
> index ad8ce77..54af34a 100644
> --- a/hw/misc/vfio.c
> +++ b/hw/misc/vfio.c
> @@ -646,7 +646,7 @@ static int vfio_msix_vector_do_use(PCIDevice
> *pdev, unsigned int nr,
>      vector->virq = msg ? kvm_irqchip_add_msi_route(kvm_state, *msg) : -1;
>      if (vector->virq < 0 ||
>          kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> -                                       vector->virq) < 0) {
> +                                       NULL, vector->virq) < 0) {
>          if (vector->virq >= 0) {
>              kvm_irqchip_release_virq(kvm_state, vector->virq);
>              vector->virq = -1;
> @@ -814,7 +814,7 @@ retry:
>          vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
>          if (vector->virq < 0 ||
>              kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
> -                                           vector->virq) < 0) {
> +                                           NULL, vector->virq) < 0) {
>              qemu_set_fd_handler(event_notifier_get_fd(&vector->interrupt),
>                                  vfio_msi_interrupt, NULL, vector);
>          }


Why doesn't this address the only current user of
KVM_IRQFD_FLAG_RESAMPLE, vfio_enable_intx_kvm()?  Thanks,

Alex


> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index c38cfd1..c4db407 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -508,7 +508,7 @@ static int kvm_virtio_pci_irqfd_use(VirtIOPCIProxy *proxy,
>      VirtQueue *vq = virtio_get_queue(proxy->vdev, queue_no);
>      EventNotifier *n = virtio_queue_get_guest_notifier(vq);
>      int ret;
> -    ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, irqfd->virq);
> +    ret = kvm_irqchip_add_irqfd_notifier(kvm_state, n, NULL, irqfd->virq);
>      return ret;
>  }
> 
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 1e08a85..9e5d78e 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -309,7 +309,8 @@ int kvm_irqchip_add_msi_route(KVMState *s, MSIMessage 
> msg);
>  int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg);
>  void kvm_irqchip_release_virq(KVMState *s, int virq);
> 
> -int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n, int virq);
> +int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n,
> +                                   EventNotifier *rn, int virq);
>  int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n, int 
> virq);
>  void kvm_pc_gsi_handler(void *opaque, int n, int level);
>  void kvm_pc_setup_irq_routing(bool pci_enabled);
> diff --git a/kvm-all.c b/kvm-all.c
> index 232c39a..3f69b41 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1230,7 +1230,8 @@ int kvm_irqchip_update_msi_route(KVMState *s,
> int virq, MSIMessage msg)
>      return kvm_update_routing_entry(s, &kroute);
>  }
> 
> -static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int virq, bool 
> assign)
> +static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int rfd, int virq,
> +                                    bool assign)
>  {
>      struct kvm_irqfd irqfd = {
>          .fd = fd,
> @@ -1238,6 +1239,11 @@ static int kvm_irqchip_assign_irqfd(KVMState
> *s, int fd, int virq, bool assign)
>          .flags = assign ? 0 : KVM_IRQFD_FLAG_DEASSIGN,
>      };
> 
> +    if (rfd != -1) {
> +        irqfd.flags |= KVM_IRQFD_FLAG_RESAMPLE;
> +        irqfd.resamplefd = rfd;
> +    }
> +
>      if (!kvm_irqfds_enabled()) {
>          return -ENOSYS;
>      }
> @@ -1276,14 +1282,17 @@ int kvm_irqchip_update_msi_route(KVMState *s,
> int virq, MSIMessage msg)
>  }
>  #endif /* !KVM_CAP_IRQ_ROUTING */
> 
> -int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n, int virq)
> +int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n,
> +                                   EventNotifier *rn, int virq)
>  {
> -    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), virq, true);
> +    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n),
> +           rn ? event_notifier_get_fd(rn) : -1, virq, true);
>  }
> 
>  int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n, int 
> virq)
>  {
> -    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), virq, 
> false);
> +    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), -1, virq,
> +           false);
>  }
> 
>  static int kvm_irqchip_create(KVMState *s)
> --
> 1.8.3.3