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Re: [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices.
From: |
Cornelia Huck |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 3/4] KVM: ioeventfd for s390 css devices. |
Date: |
Mon, 25 Feb 2013 09:49:01 +0100 |
On Sun, 24 Feb 2013 11:47:50 +0200
"Michael S. Tsirkin" <address@hidden> wrote:
> 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?
How about KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY?
> Also, maybe we want to add KVM_IOEVENTFD_S390_VIRTIO_NOTIFY as well?
No, since s390-virtio is a dead end.
>
> >
> > #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
- [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