On Fri, Apr 23, 2021 at 10:28:32AM -0700, Jianxiong Gao wrote: > > How? Anything that installed 5.10 when it was released never had this > > working, they had to move to 5.12 to get that to work. > > I wasn't clear. The bug is not specific to SEV virtualization. We > simply encountered it while working on SEV virtualization. This is a > pre-existing bug. > > Briefly, the NVMe spec expects a page offset to be retained from the > memory address space to the IO address space. > > Before these patches, the SWIOTLB truncates any page offset. > > Thus, all NVMe + SWIOTLB systems are broken due to this bug without > these patches. Ok, and what prevents you from adding this new feature do your "custom" kernel, or to use 5.12 instead? This is a new feature that Linux has never supported, and these patches are not "trivial" at all. I also do not see the maintainer of the subsystem agreeing that these are needed to be backported, which is not a good sign. So I recommend just using a newer kernel version, that way all will be good and no need to backport anything. What is preventing you from doing that today? thanks, greg k-h
