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Re: [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices.
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices. |
Date: |
Sun, 24 Feb 2013 11:47:50 +0200 |
On Fri, Feb 22, 2013 at 01:09:48PM +0100, Cornelia Huck wrote:
> Enhance KVM_IOEVENTFD with a new flag that allows to attach to s390 css
> devices.
>
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
> Documentation/virtual/kvm/api.txt | 7 +++++++
> include/uapi/linux/kvm.h | 2 ++
> virt/kvm/eventfd.c | 8 ++++++--
> 3 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt
> b/Documentation/virtual/kvm/api.txt
> index c2534c3..40e799c 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -1468,15 +1468,22 @@ struct kvm_ioeventfd {
> __u8 pad[36];
> };
>
> +For the special case of s390 css devices, the ioevent is matched to a
> +subchannel/virtqueue tuple instead.
> +
> The following flags are defined:
>
> #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
> #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
> #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
> +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css)
>
> If datamatch flag is set, the event will be signaled only if the written
> value
> to the registered address is equal to datamatch in struct kvm_ioeventfd.
>
> +For css devices, addr contains the subchannel id and datamatch the virtqueue
> +index.
> +
>
> 4.60 KVM_DIRTY_TLB
>
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 9a2db57..1df0766 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -448,12 +448,14 @@ enum {
> kvm_ioeventfd_flag_nr_datamatch,
> kvm_ioeventfd_flag_nr_pio,
> kvm_ioeventfd_flag_nr_deassign,
> + kvm_ioeventfd_flag_nr_css,
> kvm_ioeventfd_flag_nr_max,
> };
>
> #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
> #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
> #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
> +#define KVM_IOEVENTFD_FLAG_CSS (1 << kvm_ioeventfd_flag_nr_css)
So let's explicitly name is KVM_IOEVENTFD_S390_VIRTIO_CCW or even
KVM_IOEVENTFD_S390_VIRTIO_CCW_NOTIFY?
Also, maybe we want to add KVM_IOEVENTFD_S390_VIRTIO_NOTIFY as well?
>
> #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1)
>
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index f0ced1a..7347652 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -679,11 +679,13 @@ static int
> kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
> {
> int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
> - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
> + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS;
> + enum kvm_bus bus_idx;
> struct _ioeventfd *p;
> struct eventfd_ctx *eventfd;
> int ret;
>
> + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS;
> /* must be natural-word sized */
> switch (args->len) {
> case 1:
> @@ -759,11 +761,13 @@ static int
> kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
> {
> int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
> - enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
> + int css = args->flags & KVM_IOEVENTFD_FLAG_CSS;
> + enum kvm_bus bus_idx;
> struct _ioeventfd *p, *tmp;
> struct eventfd_ctx *eventfd;
> int ret = -ENOENT;
>
> + bus_idx = pio ? KVM_PIO_BUS : css ? KVM_CSS_BUS: KVM_MMIO_BUS;
> eventfd = eventfd_ctx_fdget(args->fd);
> if (IS_ERR(eventfd))
> return PTR_ERR(eventfd);
> --
> 1.7.12.4
- [Qemu-devel] [RFC PATCH v2 0/4] kvm: Make ioeventfd usable on s390., Cornelia Huck, 2013/02/22
- [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices., Cornelia Huck, 2013/02/22
- Re: [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices.,
Michael S. Tsirkin <=
- [Qemu-devel] [RFC PATCH v2 4/4] KVM: s390: Wire up ioeventfd., Cornelia Huck, 2013/02/22
- [Qemu-devel] [RFC PATCH v2 1/4] KVM: Initialize irqfd from kvm_init()., Cornelia Huck, 2013/02/22
- [Qemu-devel] [RFC PATCH v2 2/4] KVM: Introduce KVM_CSS_BUS., Cornelia Huck, 2013/02/22
- Re: [Qemu-devel] [RFC PATCH v2 0/4] kvm: Make ioeventfd usable on s390., Michael S. Tsirkin, 2013/02/24
- Re: [Qemu-devel] [RFC PATCH v2 0/4] kvm: Make ioeventfd usable on s390., Michael S. Tsirkin, 2013/02/24