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KVM: ioeventfd for virtio-ccw devices. 

Enhance KVM_IOEVENTFD with a new flag that allows to attach to virtio-ccw
devices on s390 via the KVM_VIRTIO_CCW_NOTIFY_BUS.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Cornelia Huck 2013-02-28 12:33:20 +01:00 committed by Marcelo Tosatti
parent 060f0ce6ff
commit 2b83451b45
3 changed files with 24 additions and 4 deletions
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8
Documentation/virtual/kvm/api.txt
View File

@ -1486,15 +1486,23 @@ struct kvm_ioeventfd {
__u8 pad[36];
};
For the special case of virtio-ccw devices on s390, 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_VIRTIO_CCW_NOTIFY \
(1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify)
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 virtio-ccw devices, addr contains the subchannel id and datamatch the
virtqueue index.
4.60 KVM_DIRTY_TLB

3
include/uapi/linux/kvm.h
View File

@ -449,12 +449,15 @@ enum {
kvm_ioeventfd_flag_nr_datamatch,
kvm_ioeventfd_flag_nr_pio,
kvm_ioeventfd_flag_nr_deassign,
kvm_ioeventfd_flag_nr_virtio_ccw_notify,
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_VIRTIO_CCW_NOTIFY \
(1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify)
#define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1)

17
virt/kvm/eventfd.c
View File

@ -674,15 +674,24 @@ ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
return false;
}
static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
{
if (flags & KVM_IOEVENTFD_FLAG_PIO)
return KVM_PIO_BUS;
if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
return KVM_VIRTIO_CCW_NOTIFY_BUS;
return KVM_MMIO_BUS;
}
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;
enum kvm_bus bus_idx;
struct _ioeventfd *p;
struct eventfd_ctx *eventfd;
int ret;
bus_idx = ioeventfd_bus_from_flags(args->flags);
/* must be natural-word sized */
switch (args->len) {
case 1:
@ -757,12 +766,12 @@ fail:
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;
enum kvm_bus bus_idx;
struct _ioeventfd *p, *tmp;
struct eventfd_ctx *eventfd;
int ret = -ENOENT;
bus_idx = ioeventfd_bus_from_flags(args->flags);
eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);