在 2021/4/8 下午8:57, Max Gurtovoy 写道:
On 4/8/2021 3:45 PM, Jason Wang wrote:
在 2021/4/8 下午5:44, Max Gurtovoy 写道:
On 4/8/2021 12:01 PM, Jason Wang wrote:
在 2021/4/8 下午4:11, Max Gurtovoy 写道:
According to the spec after writing 0 to device_status, the driver
MUST
wait for a read of device_status to return 0 before reinitializing
the
device. In case we have a device that won't return 0, the reset
operation will loop forever and cause the host/vm to stuck. Set
timeout
for 3 minutes before giving up on the device.
Signed-off-by: Max Gurtovoy <mgurtovoy@xxxxxxxxxx>
---
drivers/virtio/virtio_pci_modern.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
index cc3412a96a17..dcee616e8d21 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -162,6 +162,7 @@ static int vp_reset(struct virtio_device *vdev)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
struct virtio_pci_modern_device *mdev = &vp_dev->mdev;
+ unsigned long timeout = jiffies + msecs_to_jiffies(180000);
/* 0 status means a reset. */
vp_modern_set_status(mdev, 0);
@@ -169,9 +170,16 @@ static int vp_reset(struct virtio_device *vdev)
* device_status to return 0 before reinitializing the device.
* This will flush out the status write, and flush in device
writes,
* including MSI-X interrupts, if any.
+ * Set a timeout before giving up on the device.
*/
- while (vp_modern_get_status(mdev))
+ while (vp_modern_get_status(mdev)) {
+ if (time_after(jiffies, timeout)) {
What happens if the device finish the rest after the timeout?
The driver will set VIRTIO_CONFIG_S_FAILED and one can re-probe it
later on (e.g by re-scanning the pci bus).
Ok, so do we need the flush through vp_synchronize_vectors() here?
If the device didn't write 0 to status I guess we don't need that.
The device shouldn't raise any interrupt before negotiation finish
successfully.
The reset could be triggered in other places like driver removing.
Thanks
MST, is that correct ?
Thanks
Thanks
+ dev_err(&vdev->dev, "virtio: device not ready. "
+ "Aborting. Try again later\n");
+ return -EAGAIN;
+ }
msleep(1);
+ }
/* Flush pending VQ/configuration callbacks. */
vp_synchronize_vectors(vdev);
return 0;
