RE: A problem of Intel IOMMU hardware ？

[Tian, Kevin]

> From: iommu <iommu-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx> On Behalf Of
> Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
> 
> > 2. Consider ensuring that the problem is not somehow related to queued
> > invalidations. Try to use __iommu_flush_iotlb() instead of qi_flush_iotlb().
> >
> 
> I tried to force to use __iommu_flush_iotlb(), but maybe something wrong,
> the system crashed, so I prefer to lower the priority of this operation.
> 

The VT-d spec clearly says that register-based invalidation can be used
only when queued-invalidations are not enabled. Intel-IOMMU driver
doesn't provide an option to disable queued-invalidation though, when
the hardware is capable. If you really want to try, tweak the code in
intel_iommu_init_qi.

Thanks
Kevin