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[Qemu-devel] [PATCH RFC 5/8] vfio: ccw: realize VFIO_DEVICE_CCW_HOT_RESE
From: |
Dong Jia Shi |
Subject: |
[Qemu-devel] [PATCH RFC 5/8] vfio: ccw: realize VFIO_DEVICE_CCW_HOT_RESET ioctl |
Date: |
Fri, 29 Apr 2016 14:11:52 +0200 |
Introduce VFIO_DEVICE_CCW_HOT_RESET ioctl for vfio-ccw to make it
possible to hot-reset the device.
We try to achieve a hot reset by first offlining the device and then
onlining it again: this should clear all state at the subchannel.
Signed-off-by: Dong Jia Shi <address@hidden>
Reviewed-by: Pierre Morel <address@hidden>
---
drivers/vfio/ccw/vfio_ccw.c | 50 ++++++++++++++++++++++++++++++++++++++++++++-
include/uapi/linux/vfio.h | 8 ++++++++
2 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/ccw/vfio_ccw.c b/drivers/vfio/ccw/vfio_ccw.c
index 7331aed..9700448 100644
--- a/drivers/vfio/ccw/vfio_ccw.c
+++ b/drivers/vfio/ccw/vfio_ccw.c
@@ -22,10 +22,12 @@
* struct vfio_ccw_device
* @cdev: ccw device
* @going_away: if an offline procedure was already ongoing
+ * @hot_reset: if hot-reset is ongoing
*/
struct vfio_ccw_device {
struct ccw_device *cdev;
bool going_away;
+ bool hot_reset;
};
enum vfio_ccw_device_type {
@@ -58,6 +60,7 @@ static void vfio_ccw_release(void *device_data)
static long vfio_ccw_ioctl(void *device_data, unsigned int cmd,
unsigned long arg)
{
+ struct vfio_ccw_device *vcdev = device_data;
unsigned long minsz;
if (cmd == VFIO_DEVICE_GET_INFO) {
@@ -76,6 +79,34 @@ static long vfio_ccw_ioctl(void *device_data, unsigned int
cmd,
info.num_irqs = 0;
return copy_to_user((void __user *)arg, &info, minsz);
+
+ } else if (cmd == VFIO_DEVICE_CCW_HOT_RESET) {
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+ if (!vcdev->cdev->online) {
+ spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev),
+ flags);
+ return -EINVAL;
+ }
+
+ if (vcdev->hot_reset) {
+ spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev),
+ flags);
+ return -EBUSY;
+ }
+ vcdev->hot_reset = true;
+ spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+
+ ret = ccw_device_set_offline(vcdev->cdev);
+ if (!ret)
+ ret = ccw_device_set_online(vcdev->cdev);
+
+ spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+ vcdev->hot_reset = false;
+ spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+ return ret;
}
return -ENOTTY;
@@ -108,7 +139,7 @@ static int vfio_ccw_set_offline(struct ccw_device *cdev)
vdev = vfio_device_data(device);
vfio_device_put(device);
- if (!vdev || vdev->going_away)
+ if (!vdev || vdev->hot_reset || vdev->going_away)
return 0;
vdev->going_away = true;
@@ -128,9 +159,26 @@ void vfio_ccw_remove(struct ccw_device *cdev)
static int vfio_ccw_set_online(struct ccw_device *cdev)
{
+ struct vfio_device *device = vfio_device_get_from_dev(&cdev->dev);
struct vfio_ccw_device *vdev;
int ret;
+ if (!device)
+ goto create_device;
+
+ vdev = vfio_device_data(device);
+ vfio_device_put(device);
+ if (!vdev)
+ goto create_device;
+
+ /*
+ * During hot reset, we just want to disable/enable the
+ * subchannel and need not setup anything again.
+ */
+ if (vdev->hot_reset)
+ return 0;
+
+create_device:
vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
if (!vdev)
return -ENOMEM;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index aaedfcd..889a316 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -687,6 +687,14 @@ struct vfio_iommu_spapr_tce_remove {
};
#define VFIO_IOMMU_SPAPR_TCE_REMOVE _IO(VFIO_TYPE, VFIO_BASE + 20)
+/**
+ * VFIO_DEVICE_CCW_HOT_RESET - _IOW(VFIO_TYPE, VFIO_BASE + 21)
+ *
+ * Hot reset the channel I/O device. All state of the subchannel will be
+ * cleared.
+ */
+#define VFIO_DEVICE_CCW_HOT_RESET _IO(VFIO_TYPE, VFIO_BASE + 21)
+
/* ***************************************************************** */
#endif /* _UAPIVFIO_H */
--
2.6.6
- [Qemu-devel] [PATCH RFC 0/8] basic vfio-ccw infrastructure, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 2/8] s390: move orb.h from drivers/s390/ to arch/s390/, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 7/8] vfio: ccw: introduce ccw chain interfaces, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 1/8] iommu: s390: enable iommu api for s390 ccw devices, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 4/8] vfio: ccw: realize VFIO_DEVICE_GET_INFO ioctl, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 6/8] vfio: ccw: introduce page array interfaces, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 8/8] vfio: ccw: realize VFIO_DEVICE_CCW_CMD_REQUEST ioctl, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 3/8] vfio: ccw: basic implementation for vfio_ccw driver, Dong Jia Shi, 2016/04/29
- [Qemu-devel] [PATCH RFC 5/8] vfio: ccw: realize VFIO_DEVICE_CCW_HOT_RESET ioctl,
Dong Jia Shi <=
- Re: [Qemu-devel] [PATCH RFC 0/8] basic vfio-ccw infrastructure, Alex Williamson, 2016/04/29