On Tue, May 18, 2021 at 10:18:09PM +0000, Jianxiong Gao wrote:

We observed several NVMe failures when running with SWIOTLB. The root
cause of the issue is that when data is mapped via SWIOTLB, the address
offset is not preserved. Several device drivers including the NVMe
driver relies on this offset to function correctly.

Even though we discovered the error when running using AMD SEV, we have
reproduced the same error in Rhel 8 without SEV. By adding swiotlb=force
option to the boot command line parameter, NVMe funcionality is
impacted. For example formatting a disk into xfs format returns an
error.

I still fail to understand why you can not just use the 5.10.y kernel or
newer.  What is preventing you from doing this if you wish to use this
type of hardware?  This is not a "regression" in that the 5.4.y kernel
has never worked with this hardware before, it feels like a new feature.

Please, just use 5.10.y or newer, your life will be so much easier in
the longrun.

thanks,

greg k-h