KVM: s390: Add a channel I/O based virtio transport driver.
authorCornelia Huck <cornelia.huck@de.ibm.com>
Fri, 14 Dec 2012 16:02:18 +0000 (17:02 +0100)
committerGleb Natapov <gleb@redhat.com>
Tue, 18 Dec 2012 12:37:13 +0000 (14:37 +0200)
Add a driver for kvm guests that matches virtual ccw devices provided
by the host as virtio bridge devices.

These virtio-ccw devices use a special set of channel commands in order
to perform virtio functions.

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
arch/s390/include/asm/irq.h
arch/s390/kernel/irq.c
drivers/s390/kvm/Makefile
drivers/s390/kvm/virtio_ccw.c [new file with mode: 0644]

index e6972f85d2b0926e58832e955cefb538e58618e7..aa6d0d74cec91ca06d409655a8d5bb2a60cb85e7 100644 (file)
@@ -35,6 +35,7 @@ enum interruption_class {
        IOINT_CSC,
        IOINT_PCI,
        IOINT_MSI,
+       IOINT_VIR,
        NMI_NMI,
        NR_IRQS,
 };
index bf24293970ce544b358f9bb3f4d4c7daa9bde88f..a9806ea3ebd7244db2a45b370927946fdecbfe01 100644 (file)
@@ -60,6 +60,7 @@ static const struct irq_class intrclass_names[] = {
        [IOINT_CSC]  = {.name = "CSC", .desc = "[I/O] CHSC Subchannel"},
        [IOINT_PCI]  = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
        [IOINT_MSI] =  {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
+       [IOINT_VIR]  = {.name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
        [NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
 };
 
index 0815690ac1e03cd8b7fb003e7c9fabb38804647c..241891a57caf8e97637d3e6c2ce6baecd021589a 100644 (file)
@@ -6,4 +6,4 @@
 # it under the terms of the GNU General Public License (version 2 only)
 # as published by the Free Software Foundation.
 
-obj-$(CONFIG_S390_GUEST) += kvm_virtio.o
+obj-$(CONFIG_S390_GUEST) += kvm_virtio.o virtio_ccw.o
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
new file mode 100644 (file)
index 0000000..1a5aff3
--- /dev/null
@@ -0,0 +1,853 @@
+/*
+ * ccw based virtio transport
+ *
+ * Copyright IBM Corp. 2012
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ *    Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/err.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/virtio_ring.h>
+#include <linux/pfn.h>
+#include <linux/async.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kvm_para.h>
+#include <asm/setup.h>
+#include <asm/irq.h>
+#include <asm/cio.h>
+#include <asm/ccwdev.h>
+
+/*
+ * virtio related functions
+ */
+
+struct vq_config_block {
+       __u16 index;
+       __u16 num;
+} __packed;
+
+#define VIRTIO_CCW_CONFIG_SIZE 0x100
+/* same as PCI config space size, should be enough for all drivers */
+
+struct virtio_ccw_device {
+       struct virtio_device vdev;
+       __u8 status;
+       __u8 config[VIRTIO_CCW_CONFIG_SIZE];
+       struct ccw_device *cdev;
+       struct ccw1 *ccw;
+       __u32 area;
+       __u32 curr_io;
+       int err;
+       wait_queue_head_t wait_q;
+       spinlock_t lock;
+       struct list_head virtqueues;
+       unsigned long indicators;
+       unsigned long indicators2;
+       struct vq_config_block *config_block;
+};
+
+struct vq_info_block {
+       __u64 queue;
+       __u32 align;
+       __u16 index;
+       __u16 num;
+} __packed;
+
+struct virtio_feature_desc {
+       __u32 features;
+       __u8 index;
+} __packed;
+
+struct virtio_ccw_vq_info {
+       struct virtqueue *vq;
+       int num;
+       void *queue;
+       struct vq_info_block *info_block;
+       struct list_head node;
+};
+
+#define KVM_VIRTIO_CCW_RING_ALIGN 4096
+
+#define KVM_S390_VIRTIO_CCW_NOTIFY 3
+
+#define CCW_CMD_SET_VQ 0x13
+#define CCW_CMD_VDEV_RESET 0x33
+#define CCW_CMD_SET_IND 0x43
+#define CCW_CMD_SET_CONF_IND 0x53
+#define CCW_CMD_READ_FEAT 0x12
+#define CCW_CMD_WRITE_FEAT 0x11
+#define CCW_CMD_READ_CONF 0x22
+#define CCW_CMD_WRITE_CONF 0x21
+#define CCW_CMD_WRITE_STATUS 0x31
+#define CCW_CMD_READ_VQ_CONF 0x32
+
+#define VIRTIO_CCW_DOING_SET_VQ 0x00010000
+#define VIRTIO_CCW_DOING_RESET 0x00040000
+#define VIRTIO_CCW_DOING_READ_FEAT 0x00080000
+#define VIRTIO_CCW_DOING_WRITE_FEAT 0x00100000
+#define VIRTIO_CCW_DOING_READ_CONFIG 0x00200000
+#define VIRTIO_CCW_DOING_WRITE_CONFIG 0x00400000
+#define VIRTIO_CCW_DOING_WRITE_STATUS 0x00800000
+#define VIRTIO_CCW_DOING_SET_IND 0x01000000
+#define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
+#define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
+#define VIRTIO_CCW_INTPARM_MASK 0xffff0000
+
+static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
+{
+       return container_of(vdev, struct virtio_ccw_device, vdev);
+}
+
+static int doing_io(struct virtio_ccw_device *vcdev, __u32 flag)
+{
+       unsigned long flags;
+       __u32 ret;
+
+       spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+       if (vcdev->err)
+               ret = 0;
+       else
+               ret = vcdev->curr_io & flag;
+       spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+       return ret;
+}
+
+static int ccw_io_helper(struct virtio_ccw_device *vcdev, __u32 intparm)
+{
+       int ret;
+       unsigned long flags;
+       int flag = intparm & VIRTIO_CCW_INTPARM_MASK;
+
+       spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+       ret = ccw_device_start(vcdev->cdev, vcdev->ccw, intparm, 0, 0);
+       if (!ret)
+               vcdev->curr_io |= flag;
+       spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+       wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
+       return ret ? ret : vcdev->err;
+}
+
+static inline long do_kvm_notify(struct subchannel_id schid,
+                                unsigned long queue_index)
+{
+       register unsigned long __nr asm("1") = KVM_S390_VIRTIO_CCW_NOTIFY;
+       register struct subchannel_id __schid asm("2") = schid;
+       register unsigned long __index asm("3") = queue_index;
+       register long __rc asm("2");
+
+       asm volatile ("diag 2,4,0x500\n"
+                     : "=d" (__rc) : "d" (__nr), "d" (__schid), "d" (__index)
+                     : "memory", "cc");
+       return __rc;
+}
+
+static void virtio_ccw_kvm_notify(struct virtqueue *vq)
+{
+       struct virtio_ccw_vq_info *info = vq->priv;
+       struct virtio_ccw_device *vcdev;
+       struct subchannel_id schid;
+
+       vcdev = to_vc_device(info->vq->vdev);
+       ccw_device_get_schid(vcdev->cdev, &schid);
+       do_kvm_notify(schid, virtqueue_get_queue_index(vq));
+}
+
+static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev, int index)
+{
+       vcdev->config_block->index = index;
+       vcdev->ccw->cmd_code = CCW_CMD_READ_VQ_CONF;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(struct vq_config_block);
+       vcdev->ccw->cda = (__u32)(unsigned long)(vcdev->config_block);
+       ccw_io_helper(vcdev, VIRTIO_CCW_DOING_READ_VQ_CONF);
+       return vcdev->config_block->num;
+}
+
+static void virtio_ccw_del_vq(struct virtqueue *vq)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vq->vdev);
+       struct virtio_ccw_vq_info *info = vq->priv;
+       unsigned long flags;
+       unsigned long size;
+       int ret;
+       unsigned int index = virtqueue_get_queue_index(vq);
+
+       /* Remove from our list. */
+       spin_lock_irqsave(&vcdev->lock, flags);
+       list_del(&info->node);
+       spin_unlock_irqrestore(&vcdev->lock, flags);
+
+       /* Release from host. */
+       info->info_block->queue = 0;
+       info->info_block->align = 0;
+       info->info_block->index = index;
+       info->info_block->num = 0;
+       vcdev->ccw->cmd_code = CCW_CMD_SET_VQ;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(*info->info_block);
+       vcdev->ccw->cda = (__u32)(unsigned long)(info->info_block);
+       ret = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_SET_VQ | index);
+       /*
+        * -ENODEV isn't considered an error: The device is gone anyway.
+        * This may happen on device detach.
+        */
+       if (ret && (ret != -ENODEV))
+               dev_warn(&vq->vdev->dev, "Error %d while deleting queue %d",
+                        ret, index);
+
+       vring_del_virtqueue(vq);
+       size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
+       free_pages_exact(info->queue, size);
+       kfree(info->info_block);
+       kfree(info);
+}
+
+static void virtio_ccw_del_vqs(struct virtio_device *vdev)
+{
+       struct virtqueue *vq, *n;
+
+       list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+               virtio_ccw_del_vq(vq);
+}
+
+static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
+                                            int i, vq_callback_t *callback,
+                                            const char *name)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+       int err;
+       struct virtqueue *vq;
+       struct virtio_ccw_vq_info *info;
+       unsigned long size;
+       unsigned long flags;
+
+       /* Allocate queue. */
+       info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
+       if (!info) {
+               dev_warn(&vcdev->cdev->dev, "no info\n");
+               err = -ENOMEM;
+               goto out_err;
+       }
+       info->info_block = kzalloc(sizeof(*info->info_block),
+                                  GFP_DMA | GFP_KERNEL);
+       if (!info->info_block) {
+               dev_warn(&vcdev->cdev->dev, "no info block\n");
+               err = -ENOMEM;
+               goto out_err;
+       }
+       info->num = virtio_ccw_read_vq_conf(vcdev, i);
+       size = PAGE_ALIGN(vring_size(info->num, KVM_VIRTIO_CCW_RING_ALIGN));
+       info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
+       if (info->queue == NULL) {
+               dev_warn(&vcdev->cdev->dev, "no queue\n");
+               err = -ENOMEM;
+               goto out_err;
+       }
+
+       vq = vring_new_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN, vdev,
+                                true, info->queue, virtio_ccw_kvm_notify,
+                                callback, name);
+       if (!vq) {
+               /* For now, we fail if we can't get the requested size. */
+               dev_warn(&vcdev->cdev->dev, "no vq\n");
+               err = -ENOMEM;
+               free_pages_exact(info->queue, size);
+               goto out_err;
+       }
+       info->vq = vq;
+       vq->priv = info;
+
+       /* Register it with the host. */
+       info->info_block->queue = (__u64)info->queue;
+       info->info_block->align = KVM_VIRTIO_CCW_RING_ALIGN;
+       info->info_block->index = i;
+       info->info_block->num = info->num;
+       vcdev->ccw->cmd_code = CCW_CMD_SET_VQ;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(*info->info_block);
+       vcdev->ccw->cda = (__u32)(unsigned long)(info->info_block);
+       err = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_SET_VQ | i);
+       if (err) {
+               dev_warn(&vcdev->cdev->dev, "SET_VQ failed\n");
+               free_pages_exact(info->queue, size);
+               info->vq = NULL;
+               vq->priv = NULL;
+               goto out_err;
+       }
+
+       /* Save it to our list. */
+       spin_lock_irqsave(&vcdev->lock, flags);
+       list_add(&info->node, &vcdev->virtqueues);
+       spin_unlock_irqrestore(&vcdev->lock, flags);
+
+       return vq;
+
+out_err:
+       if (info)
+               kfree(info->info_block);
+       kfree(info);
+       return ERR_PTR(err);
+}
+
+static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+                              struct virtqueue *vqs[],
+                              vq_callback_t *callbacks[],
+                              const char *names[])
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+       unsigned long *indicatorp = NULL;
+       int ret, i;
+
+       for (i = 0; i < nvqs; ++i) {
+               vqs[i] = virtio_ccw_setup_vq(vdev, i, callbacks[i], names[i]);
+               if (IS_ERR(vqs[i])) {
+                       ret = PTR_ERR(vqs[i]);
+                       vqs[i] = NULL;
+                       goto out;
+               }
+       }
+       ret = -ENOMEM;
+       /* We need a data area under 2G to communicate. */
+       indicatorp = kmalloc(sizeof(&vcdev->indicators), GFP_DMA | GFP_KERNEL);
+       if (!indicatorp)
+               goto out;
+       *indicatorp = (unsigned long) &vcdev->indicators;
+       /* Register queue indicators with host. */
+       vcdev->indicators = 0;
+       vcdev->ccw->cmd_code = CCW_CMD_SET_IND;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(vcdev->indicators);
+       vcdev->ccw->cda = (__u32)(unsigned long) indicatorp;
+       ret = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_SET_IND);
+       if (ret)
+               goto out;
+       /* Register indicators2 with host for config changes */
+       *indicatorp = (unsigned long) &vcdev->indicators2;
+       vcdev->indicators2 = 0;
+       vcdev->ccw->cmd_code = CCW_CMD_SET_CONF_IND;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(vcdev->indicators2);
+       vcdev->ccw->cda = (__u32)(unsigned long) indicatorp;
+       ret = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_SET_CONF_IND);
+       if (ret)
+               goto out;
+
+       kfree(indicatorp);
+       return 0;
+out:
+       kfree(indicatorp);
+       virtio_ccw_del_vqs(vdev);
+       return ret;
+}
+
+static void virtio_ccw_reset(struct virtio_device *vdev)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+       /* Zero status bits. */
+       vcdev->status = 0;
+
+       /* Send a reset ccw on device. */
+       vcdev->ccw->cmd_code = CCW_CMD_VDEV_RESET;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = 0;
+       vcdev->ccw->cda = 0;
+       ccw_io_helper(vcdev, VIRTIO_CCW_DOING_RESET);
+}
+
+static u32 virtio_ccw_get_features(struct virtio_device *vdev)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+       struct virtio_feature_desc features;
+       int ret;
+
+       /* Read the feature bits from the host. */
+       /* TODO: Features > 32 bits */
+       features.index = 0;
+       vcdev->ccw->cmd_code = CCW_CMD_READ_FEAT;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(features);
+       vcdev->ccw->cda = vcdev->area;
+       ret = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_READ_FEAT);
+       if (ret)
+               return 0;
+
+       memcpy(&features, (void *)(unsigned long)vcdev->area,
+              sizeof(features));
+       return le32_to_cpu(features.features);
+}
+
+static void virtio_ccw_finalize_features(struct virtio_device *vdev)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+       struct virtio_feature_desc features;
+       int i;
+
+       /* Give virtio_ring a chance to accept features. */
+       vring_transport_features(vdev);
+
+       for (i = 0; i < sizeof(*vdev->features) / sizeof(features.features);
+            i++) {
+               int highbits = i % 2 ? 32 : 0;
+               features.index = i;
+               features.features = cpu_to_le32(vdev->features[i / 2]
+                                               >> highbits);
+               memcpy((void *)(unsigned long)vcdev->area, &features,
+                      sizeof(features));
+               /* Write the feature bits to the host. */
+               vcdev->ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+               vcdev->ccw->flags = 0;
+               vcdev->ccw->count = sizeof(features);
+               vcdev->ccw->cda = vcdev->area;
+               ccw_io_helper(vcdev, VIRTIO_CCW_DOING_WRITE_FEAT);
+       }
+}
+
+static void virtio_ccw_get_config(struct virtio_device *vdev,
+                                 unsigned int offset, void *buf, unsigned len)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+       int ret;
+
+       /* Read the config area from the host. */
+       vcdev->ccw->cmd_code = CCW_CMD_READ_CONF;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = offset + len;
+       vcdev->ccw->cda = vcdev->area;
+       ret = ccw_io_helper(vcdev, VIRTIO_CCW_DOING_READ_CONFIG);
+       if (ret)
+               return;
+
+       memcpy(vcdev->config, (void *)(unsigned long)vcdev->area,
+              sizeof(vcdev->config));
+       memcpy(buf, &vcdev->config[offset], len);
+}
+
+static void virtio_ccw_set_config(struct virtio_device *vdev,
+                                 unsigned int offset, const void *buf,
+                                 unsigned len)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+       memcpy(&vcdev->config[offset], buf, len);
+       /* Write the config area to the host. */
+       memcpy((void *)(unsigned long)vcdev->area, vcdev->config,
+              sizeof(vcdev->config));
+       vcdev->ccw->cmd_code = CCW_CMD_WRITE_CONF;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = offset + len;
+       vcdev->ccw->cda = vcdev->area;
+       ccw_io_helper(vcdev, VIRTIO_CCW_DOING_WRITE_CONFIG);
+}
+
+static u8 virtio_ccw_get_status(struct virtio_device *vdev)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+       return vcdev->status;
+}
+
+static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
+{
+       struct virtio_ccw_device *vcdev = to_vc_device(vdev);
+
+       /* Write the status to the host. */
+       vcdev->status = status;
+       memcpy((void *)(unsigned long)vcdev->area, &status, sizeof(status));
+       vcdev->ccw->cmd_code = CCW_CMD_WRITE_STATUS;
+       vcdev->ccw->flags = 0;
+       vcdev->ccw->count = sizeof(status);
+       vcdev->ccw->cda = vcdev->area;
+       ccw_io_helper(vcdev, VIRTIO_CCW_DOING_WRITE_STATUS);
+}
+
+static struct virtio_config_ops virtio_ccw_config_ops = {
+       .get_features = virtio_ccw_get_features,
+       .finalize_features = virtio_ccw_finalize_features,
+       .get = virtio_ccw_get_config,
+       .set = virtio_ccw_set_config,
+       .get_status = virtio_ccw_get_status,
+       .set_status = virtio_ccw_set_status,
+       .reset = virtio_ccw_reset,
+       .find_vqs = virtio_ccw_find_vqs,
+       .del_vqs = virtio_ccw_del_vqs,
+};
+
+
+/*
+ * ccw bus driver related functions
+ */
+
+static void virtio_ccw_release_dev(struct device *_d)
+{
+       struct virtio_device *dev = container_of(_d, struct virtio_device,
+                                                dev);
+       struct virtio_ccw_device *vcdev = to_vc_device(dev);
+
+       kfree((void *)(unsigned long)vcdev->area);
+       kfree(vcdev->config_block);
+       kfree(vcdev->ccw);
+       kfree(vcdev);
+}
+
+static int irb_is_error(struct irb *irb)
+{
+       if (scsw_cstat(&irb->scsw) != 0)
+               return 1;
+       if (scsw_dstat(&irb->scsw) & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
+               return 1;
+       if (scsw_cc(&irb->scsw) != 0)
+               return 1;
+       return 0;
+}
+
+static struct virtqueue *virtio_ccw_vq_by_ind(struct virtio_ccw_device *vcdev,
+                                             int index)
+{
+       struct virtio_ccw_vq_info *info;
+       unsigned long flags;
+       struct virtqueue *vq;
+
+       vq = NULL;
+       spin_lock_irqsave(&vcdev->lock, flags);
+       list_for_each_entry(info, &vcdev->virtqueues, node) {
+               if (virtqueue_get_queue_index(info->vq) == index) {
+                       vq = info->vq;
+                       break;
+               }
+       }
+       spin_unlock_irqrestore(&vcdev->lock, flags);
+       return vq;
+}
+
+static void virtio_ccw_int_handler(struct ccw_device *cdev,
+                                  unsigned long intparm,
+                                  struct irb *irb)
+{
+       __u32 activity = intparm & VIRTIO_CCW_INTPARM_MASK;
+       struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
+       int i;
+       struct virtqueue *vq;
+       struct virtio_driver *drv;
+
+       /* Check if it's a notification from the host. */
+       if ((intparm == 0) &&
+           (scsw_stctl(&irb->scsw) ==
+            (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND))) {
+               /* OK */
+       }
+       if (irb_is_error(irb))
+               vcdev->err = -EIO; /* XXX - use real error */
+       if (vcdev->curr_io & activity) {
+               switch (activity) {
+               case VIRTIO_CCW_DOING_READ_FEAT:
+               case VIRTIO_CCW_DOING_WRITE_FEAT:
+               case VIRTIO_CCW_DOING_READ_CONFIG:
+               case VIRTIO_CCW_DOING_WRITE_CONFIG:
+               case VIRTIO_CCW_DOING_WRITE_STATUS:
+               case VIRTIO_CCW_DOING_SET_VQ:
+               case VIRTIO_CCW_DOING_SET_IND:
+               case VIRTIO_CCW_DOING_SET_CONF_IND:
+               case VIRTIO_CCW_DOING_RESET:
+               case VIRTIO_CCW_DOING_READ_VQ_CONF:
+                       vcdev->curr_io &= ~activity;
+                       wake_up(&vcdev->wait_q);
+                       break;
+               default:
+                       /* don't know what to do... */
+                       dev_warn(&cdev->dev, "Suspicious activity '%08x'\n",
+                                activity);
+                       WARN_ON(1);
+                       break;
+               }
+       }
+       for_each_set_bit(i, &vcdev->indicators,
+                        sizeof(vcdev->indicators) * BITS_PER_BYTE) {
+               /* The bit clear must happen before the vring kick. */
+               clear_bit(i, &vcdev->indicators);
+               barrier();
+               vq = virtio_ccw_vq_by_ind(vcdev, i);
+               vring_interrupt(0, vq);
+       }
+       if (test_bit(0, &vcdev->indicators2)) {
+               drv = container_of(vcdev->vdev.dev.driver,
+                                  struct virtio_driver, driver);
+
+               if (drv && drv->config_changed)
+                       drv->config_changed(&vcdev->vdev);
+               clear_bit(0, &vcdev->indicators2);
+       }
+}
+
+/*
+ * We usually want to autoonline all devices, but give the admin
+ * a way to exempt devices from this.
+ */
+#define __DEV_WORDS ((__MAX_SUBCHANNEL + (8*sizeof(long) - 1)) / \
+                    (8*sizeof(long)))
+static unsigned long devs_no_auto[__MAX_SSID + 1][__DEV_WORDS];
+
+static char *no_auto = "";
+
+module_param(no_auto, charp, 0444);
+MODULE_PARM_DESC(no_auto, "list of ccw bus id ranges not to be auto-onlined");
+
+static int virtio_ccw_check_autoonline(struct ccw_device *cdev)
+{
+       struct ccw_dev_id id;
+
+       ccw_device_get_id(cdev, &id);
+       if (test_bit(id.devno, devs_no_auto[id.ssid]))
+               return 0;
+       return 1;
+}
+
+static void virtio_ccw_auto_online(void *data, async_cookie_t cookie)
+{
+       struct ccw_device *cdev = data;
+       int ret;
+
+       ret = ccw_device_set_online(cdev);
+       if (ret)
+               dev_warn(&cdev->dev, "Failed to set online: %d\n", ret);
+}
+
+static int virtio_ccw_probe(struct ccw_device *cdev)
+{
+       cdev->handler = virtio_ccw_int_handler;
+
+       if (virtio_ccw_check_autoonline(cdev))
+               async_schedule(virtio_ccw_auto_online, cdev);
+       return 0;
+}
+
+static void virtio_ccw_remove(struct ccw_device *cdev)
+{
+       struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
+
+       if (cdev->online) {
+               unregister_virtio_device(&vcdev->vdev);
+               dev_set_drvdata(&cdev->dev, NULL);
+       }
+       cdev->handler = NULL;
+}
+
+static int virtio_ccw_offline(struct ccw_device *cdev)
+{
+       struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev);
+
+       unregister_virtio_device(&vcdev->vdev);
+       dev_set_drvdata(&cdev->dev, NULL);
+       return 0;
+}
+
+
+/* Area needs to be big enough to fit status, features or configuration. */
+#define VIRTIO_AREA_SIZE VIRTIO_CCW_CONFIG_SIZE /* biggest possible use */
+
+static int virtio_ccw_online(struct ccw_device *cdev)
+{
+       int ret;
+       struct virtio_ccw_device *vcdev;
+
+       vcdev = kzalloc(sizeof(*vcdev), GFP_KERNEL);
+       if (!vcdev) {
+               dev_warn(&cdev->dev, "Could not get memory for virtio\n");
+               ret = -ENOMEM;
+               goto out_free;
+       }
+       vcdev->area = (__u32)(unsigned long)kzalloc(VIRTIO_AREA_SIZE,
+                                                   GFP_DMA | GFP_KERNEL);
+       if (!vcdev->area) {
+               dev_warn(&cdev->dev, "Cound not get memory for virtio\n");
+               ret = -ENOMEM;
+               goto out_free;
+       }
+       vcdev->config_block = kzalloc(sizeof(*vcdev->config_block),
+                                  GFP_DMA | GFP_KERNEL);
+       if (!vcdev->config_block) {
+               ret = -ENOMEM;
+               goto out_free;
+       }
+       vcdev->ccw = kzalloc(sizeof(*vcdev->ccw), GFP_DMA | GFP_KERNEL);
+       if (!vcdev->ccw) {
+               ret = -ENOMEM;
+               goto out_free;
+       }
+
+       vcdev->vdev.dev.parent = &cdev->dev;
+       vcdev->vdev.dev.release = virtio_ccw_release_dev;
+       vcdev->vdev.config = &virtio_ccw_config_ops;
+       vcdev->cdev = cdev;
+       init_waitqueue_head(&vcdev->wait_q);
+       INIT_LIST_HEAD(&vcdev->virtqueues);
+       spin_lock_init(&vcdev->lock);
+
+       dev_set_drvdata(&cdev->dev, vcdev);
+       vcdev->vdev.id.vendor = cdev->id.cu_type;
+       vcdev->vdev.id.device = cdev->id.cu_model;
+       ret = register_virtio_device(&vcdev->vdev);
+       if (ret) {
+               dev_warn(&cdev->dev, "Failed to register virtio device: %d\n",
+                        ret);
+               goto out_put;
+       }
+       return 0;
+out_put:
+       dev_set_drvdata(&cdev->dev, NULL);
+       put_device(&vcdev->vdev.dev);
+       return ret;
+out_free:
+       if (vcdev) {
+               kfree((void *)(unsigned long)vcdev->area);
+               kfree(vcdev->config_block);
+               kfree(vcdev->ccw);
+       }
+       kfree(vcdev);
+       return ret;
+}
+
+static int virtio_ccw_cio_notify(struct ccw_device *cdev, int event)
+{
+       /* TODO: Check whether we need special handling here. */
+       return 0;
+}
+
+static struct ccw_device_id virtio_ids[] = {
+       { CCW_DEVICE(0x3832, 0) },
+       {},
+};
+MODULE_DEVICE_TABLE(ccw, virtio_ids);
+
+static struct ccw_driver virtio_ccw_driver = {
+       .driver = {
+               .owner = THIS_MODULE,
+               .name = "virtio_ccw",
+       },
+       .ids = virtio_ids,
+       .probe = virtio_ccw_probe,
+       .remove = virtio_ccw_remove,
+       .set_offline = virtio_ccw_offline,
+       .set_online = virtio_ccw_online,
+       .notify = virtio_ccw_cio_notify,
+       .int_class = IOINT_VIR,
+};
+
+static int __init pure_hex(char **cp, unsigned int *val, int min_digit,
+                          int max_digit, int max_val)
+{
+       int diff;
+
+       diff = 0;
+       *val = 0;
+
+       while (diff <= max_digit) {
+               int value = hex_to_bin(**cp);
+
+               if (value < 0)
+                       break;
+               *val = *val * 16 + value;
+               (*cp)++;
+               diff++;
+       }
+
+       if ((diff < min_digit) || (diff > max_digit) || (*val > max_val))
+               return 1;
+
+       return 0;
+}
+
+static int __init parse_busid(char *str, unsigned int *cssid,
+                             unsigned int *ssid, unsigned int *devno)
+{
+       char *str_work;
+       int rc, ret;
+
+       rc = 1;
+
+       if (*str == '\0')
+               goto out;
+
+       str_work = str;
+       ret = pure_hex(&str_work, cssid, 1, 2, __MAX_CSSID);
+       if (ret || (str_work[0] != '.'))
+               goto out;
+       str_work++;
+       ret = pure_hex(&str_work, ssid, 1, 1, __MAX_SSID);
+       if (ret || (str_work[0] != '.'))
+               goto out;
+       str_work++;
+       ret = pure_hex(&str_work, devno, 4, 4, __MAX_SUBCHANNEL);
+       if (ret || (str_work[0] != '\0'))
+               goto out;
+
+       rc = 0;
+out:
+       return rc;
+}
+
+static void __init no_auto_parse(void)
+{
+       unsigned int from_cssid, to_cssid, from_ssid, to_ssid, from, to;
+       char *parm, *str;
+       int rc;
+
+       str = no_auto;
+       while ((parm = strsep(&str, ","))) {
+               rc = parse_busid(strsep(&parm, "-"), &from_cssid,
+                                &from_ssid, &from);
+               if (rc)
+                       continue;
+               if (parm != NULL) {
+                       rc = parse_busid(parm, &to_cssid,
+                                        &to_ssid, &to);
+                       if ((from_ssid > to_ssid) ||
+                           ((from_ssid == to_ssid) && (from > to)))
+                               rc = -EINVAL;
+               } else {
+                       to_cssid = from_cssid;
+                       to_ssid = from_ssid;
+                       to = from;
+               }
+               if (rc)
+                       continue;
+               while ((from_ssid < to_ssid) ||
+                      ((from_ssid == to_ssid) && (from <= to))) {
+                       set_bit(from, devs_no_auto[from_ssid]);
+                       from++;
+                       if (from > __MAX_SUBCHANNEL) {
+                               from_ssid++;
+                               from = 0;
+                       }
+               }
+       }
+}
+
+static int __init virtio_ccw_init(void)
+{
+       /* parse no_auto string before we do anything further */
+       no_auto_parse();
+       return ccw_driver_register(&virtio_ccw_driver);
+}
+module_init(virtio_ccw_init);
+
+static void __exit virtio_ccw_exit(void)
+{
+       ccw_driver_unregister(&virtio_ccw_driver);
+}
+module_exit(virtio_ccw_exit);