iommu/vt-d: Fix IQE handling to cover all descriptors in submission range

When an Invalidation Queue Error (IQE) occurs, hardware halts fetching
and IQH points at the faulting descriptor. The previous code only
checked whether IQH matched the first descriptor index of the current
submission, missing faults on any other descriptor within the batch.

Expand the check to cover the entire submission range [index, wait_index],
accounting for circular wrap-around.

Furthermore, after detecting IQE, the old recovery only replaced the
single faulting slot with a copy of the wait descriptor and immediately
returned -EINVAL. This left two problems:

  a) Hardware resumed fetching and could hit another invalid descriptor
     in the same abandoned batch, raising a second IQE that no submitter
     would claim — permanently deadlocking the queue.

  b) The caller reclaimed all batch slots (QI_FREE) while hardware might
     still be asynchronously processing descriptors from that batch,
     allowing concurrent overwrite and descriptor corruption.

Fix both by introducing qi_drain_remaining_descs(): upon IQE detection,
overwrite the stranded slots in [IQH, wait_index) with fenced no-op wait
descriptors, resubmit the wait descriptor at wait_index, clear IQE, and
spin until hardware signals QI_DONE (with DMAR_OPERATION_TIMEOUT). This
guarantees hardware has fully drained the batch before the caller
reclaims slots.

Fixes: 8a1d82462540 ("iommu/vt-d: Multiple descriptors per qi_submit_sync()")
Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

0 files changed, 0 insertions, 0 deletions