[Qemu-devel] [PATCH RFC v3 11/15] vfio: ccw: realize VFIO_DEVICE_G(S)ET_IRQ_INFO ioctls

[Dong Jia Shi]

Realize VFIO_DEVICE_GET_IRQ_INFO ioctl to retrieve
VFIO_CCW_IO_IRQ information.

Realize VFIO_DEVICE_SET_IRQS ioctl to set an eventfd fd for
VFIO_CCW_IO_IRQ. Once a write operation to the ccw_io_region
was performed, trigger a signal on this fd.

Signed-off-by: Dong Jia Shi <address@hidden>
Reviewed-by: Pierre Morel <address@hidden>
---
 drivers/s390/cio/vfio_ccw_ops.c     | 123 +++++++++++++++++++++++++++++++++++-
 drivers/s390/cio/vfio_ccw_private.h |   4 ++
 include/uapi/linux/vfio.h           |  10 ++-
 3 files changed, 134 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 125818c..ebc38fb 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -202,6 +202,9 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
        if (region->ret_code != 0)
                return region->ret_code;
 
+       if (private->io_trigger)
+               eventfd_signal(private->io_trigger, 1);
+
        return count;
 }
 
@@ -209,7 +212,7 @@ static int vfio_ccw_mdev_get_device_info(struct 
vfio_device_info *info)
 {
        info->flags = VFIO_DEVICE_FLAGS_CCW | VFIO_DEVICE_FLAGS_RESET;
        info->num_regions = VFIO_CCW_NUM_REGIONS;
-       info->num_irqs = 0;
+       info->num_irqs = VFIO_CCW_NUM_IRQS;
 
        return 0;
 }
@@ -230,6 +233,83 @@ static int vfio_ccw_mdev_get_region_info(struct 
vfio_region_info *info,
        }
 }
 
+int vfio_ccw_mdev_get_irq_info(struct vfio_irq_info *info)
+{
+       if (info->index != VFIO_CCW_IO_IRQ_INDEX)
+               return -EINVAL;
+
+       info->count = 1;
+       info->flags = VFIO_IRQ_INFO_EVENTFD | VFIO_IRQ_INFO_NORESIZE;
+
+       return 0;
+}
+
+static int vfio_ccw_mdev_set_irqs(struct mdev_device *mdev,
+                                 uint32_t flags,
+                                 void __user *data)
+{
+       struct vfio_ccw_private *private;
+       struct eventfd_ctx **ctx;
+
+       if (!(flags & VFIO_IRQ_SET_ACTION_TRIGGER))
+               return -EINVAL;
+
+       private = dev_get_drvdata(mdev_parent_dev(mdev));
+       if (!private)
+               return -ENODEV;
+
+       ctx = &private->io_trigger;
+
+       switch (flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
+       case VFIO_IRQ_SET_DATA_NONE:
+       {
+               if (*ctx)
+                       eventfd_signal(*ctx, 1);
+               return 0;
+       }
+       case VFIO_IRQ_SET_DATA_BOOL:
+       {
+               uint8_t trigger;
+
+               if (get_user(trigger, (uint8_t __user *)data))
+                       return -EFAULT;
+
+               if (trigger && *ctx)
+                       eventfd_signal(*ctx, 1);
+               return 0;
+       }
+       case VFIO_IRQ_SET_DATA_EVENTFD:
+       {
+               int32_t fd;
+
+               if (get_user(fd, (int32_t __user *)data))
+                       return -EFAULT;
+
+               if (fd == -1) {
+                       if (*ctx)
+                               eventfd_ctx_put(*ctx);
+                       *ctx = NULL;
+               } else if (fd >= 0) {
+                       struct eventfd_ctx *efdctx;
+
+                       efdctx = eventfd_ctx_fdget(fd);
+                       if (IS_ERR(efdctx))
+                               return PTR_ERR(efdctx);
+
+                       if (*ctx)
+                               eventfd_ctx_put(*ctx);
+
+                       *ctx = efdctx;
+               } else
+                       return -EINVAL;
+
+               return 0;
+       }
+       default:
+               return -EINVAL;
+       }
+}
+
 static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
                                   unsigned int cmd,
                                   unsigned long arg)
@@ -277,6 +357,47 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device 
*mdev,
 
                return copy_to_user((void __user *)arg, &info, minsz);
        }
+       case VFIO_DEVICE_GET_IRQ_INFO:
+       {
+               struct vfio_irq_info info;
+
+               minsz = offsetofend(struct vfio_irq_info, count);
+
+               if (copy_from_user(&info, (void __user *)arg, minsz))
+                       return -EFAULT;
+
+               if (info.argsz < minsz || info.index >= VFIO_CCW_NUM_IRQS)
+                       return -EINVAL;
+
+               ret = vfio_ccw_mdev_get_irq_info(&info);
+               if (ret)
+                       return ret;
+
+               if (info.count == -1)
+                       return -EINVAL;
+
+               return copy_to_user((void __user *)arg, &info, minsz);
+       }
+       case VFIO_DEVICE_SET_IRQS:
+       {
+               struct vfio_irq_set hdr;
+               size_t data_size;
+               void __user *data;
+
+               minsz = offsetofend(struct vfio_irq_set, count);
+
+               if (copy_from_user(&hdr, (void __user *)arg, minsz))
+                       return -EFAULT;
+
+               ret = vfio_set_irqs_validate_and_prepare(&hdr, 1,
+                                                        VFIO_CCW_NUM_IRQS,
+                                                        &data_size);
+               if (ret)
+                       return ret;
+
+               data = (void __user *)(arg + minsz);
+               return vfio_ccw_mdev_set_irqs(mdev, hdr.flags, data);
+       }
        case VFIO_DEVICE_RESET:
                return vfio_ccw_mdev_reset(mdev);
        default:
diff --git a/drivers/s390/cio/vfio_ccw_private.h 
b/drivers/s390/cio/vfio_ccw_private.h
index 79e5337..dddab52 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -11,6 +11,7 @@
 #define _VFIO_CCW_PRIVATE_H_
 
 #include <linux/completion.h>
+#include <linux/eventfd.h>
 #include <linux/vfio_ccw.h>
 
 #include "css.h"
@@ -29,6 +30,7 @@
  * @cp: channel program for the current I/O operation
  * @irb: irb info received from interrupt
  * @scsw: scsw info
+ * @io_trigger: eventfd ctx for signaling userspace I/O results
  */
 struct vfio_ccw_private {
        struct subchannel       *sch;
@@ -43,6 +45,8 @@ struct vfio_ccw_private {
        struct channel_program  cp;
        struct irb              irb;
        union scsw              scsw;
+
+       struct eventfd_ctx      *io_trigger;
 } __aligned(8);
 
 extern int vfio_ccw_mdev_reg(struct subchannel *sch);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 3fd70ff..ae46105 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -449,8 +449,9 @@ enum {
 };
 
 /*
- * The vfio-ccw bus driver makes use of the following fixed region.
- * Unimplemented regions return a size of zero.
+ * The vfio-ccw bus driver makes use of the following fixed region and
+ * IRQ index mapping. Unimplemented regions return a size of zero.
+ * Unimplemented IRQ types return a count of zero.
  */
 
 enum {
@@ -458,6 +459,11 @@ enum {
        VFIO_CCW_NUM_REGIONS
 };
 
+enum {
+       VFIO_CCW_IO_IRQ_INDEX,
+       VFIO_CCW_NUM_IRQS
+};
+
 /**
  * VFIO_DEVICE_GET_PCI_HOT_RESET_INFO - _IORW(VFIO_TYPE, VFIO_BASE + 12,
  *                                           struct vfio_pci_hot_reset_info)
-- 
2.8.4