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? 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;
