[PATCH v3 4/5] KVM: ioeventfd for virtio-ccw devices.

Cornelia Huck
2013-02-25T15:27:59Z

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>
---
Documentation/virtual/kvm/api.txt | 8 ++++++++
include/uapi/linux/kvm.h | 3 +++
virt/kvm/eventfd.c | 14 ++++++++++++--
3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c2534c3..86232d6 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1468,15 +1468,23 @@ 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

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 9a2db57..8f3e5ae 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -448,12 +448,15 @@ 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)

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index f0ced1a..8de3cd7 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -679,11 +679,16 @@ 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 ccw;
+ enum kvm_bus bus_idx;
struct _ioeventfd *p;
struct eventfd_ctx *eventfd;
int ret;

+ ccw = args->flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY;
+ bus_idx = pio ? KVM_PIO_BUS :
+ ccw ? KVM_VIRTIO_CCW_NOTIFY_BUS :
+ KVM_MMIO_BUS;
/* must be natural-word sized */
switch (args->len) {
case 1:
@@ -759,11 +764,16 @@ 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 ccw;
+ enum kvm_bus bus_idx;
struct _ioeventfd *p, *tmp;
struct eventfd_ctx *eventfd;
int ret = -ENOENT;

+ ccw = args->flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY;
+ bus_idx = pio ? KVM_PIO_BUS :
+ ccw ? KVM_VIRTIO_CCW_NOTIFY_BUS :
+ KVM_MMIO_BUS;
eventfd = eventfd_ctx_fdget(args->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
--
1.7.12.4