> On Mar 16, 2021, at 8:16 PM, Longpeng (Mike, Cloud Infrastructure Service > Product Dept.) <longpe...@huawei.com> wrote: > > Hi guys, > > We find the Intel iommu cache (i.e. iotlb) maybe works wrong in a special > situation, it would cause DMA fails or get wrong data. > > The reproducer (based on Alex's vfio testsuite[1]) is in attachment, it can > reproduce the problem with high probability (~50%).
I saw Lu replied, and he is much more knowledgable than I am (I was just intrigued by your email). However, if I were you I would try also to remove some “optimizations” to look for the root-cause (e.g., use domain specific invalidations instead of page-specific). The first thing that comes to my mind is the invalidation hint (ih) in iommu_flush_iotlb_psi(). I would remove it to see whether you get the failure without it.
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