On 2021/10/19 15:46, Vincent Whitchurch wrote:
The driver currently assumes that the notify callback is only received when the device is done with all the queued buffers. However, this is not true, since the notify callback could be called without any of the queued buffers being completed (for example, with virtio-pci and shared interrupts) or with only some of the buffers being completed (since the driver makes them available to the device in multiple separate virtqueue_add_sgs() calls).
Can the backend driver control the time point of interrupt injection ? I can't think of
why the backend has to send an early interrupt. This operation should be avoided
in the backend driver if possible. However, this change make sense if early interrupt
can't be avoid.
This can lead to incorrect data on the I2C bus or memory corruption in the guest if the device operates on buffers which are have been freed by the driver. (The WARN_ON in the driver is also triggered.)
