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"AlignmentMask" member in PORT_CONFIGURATION_INFORMATION structure affecting Creation Of Shielded VM RRS feed

  • General discussion

  • I am trying to create a shielded VM on an NVMe drive which is claimed by my custom NVMe driver. Upon debugging, I found that shielded VM creation is failing due to DMA data transfer error.
    The "AlignmentMask" member of PORT_CONFIGURATION_INFORMATION in my driver is (0x1) WORD aligned. When I changed it to (0x7)QUAD aligned, there is no data transfer error and shielded VM creation is successful. I have a couple of queries.
    1) How "AlignmentMask" is affecting the data transfer/creation of shielded VM?
    2) In normal IOs using IOmeter, no data transfer errors are observed. Why this "AlignmentMask" is affecting the data transfer only in creation of shielded VM?



    Thursday, November 21, 2019 10:43 AM