Re: DAX filesystem support on ARMv8

[Dan Williams]

On Mon, Nov 11, 2019 at 6:12 PM Bharat Kumar Gogada <bharatku@xxxxxxxxxx> wrote:
>
> Hi All,
>
> As per Documentation/filesystems/dax.txt
>
> The DAX code does not work correctly on architectures which have virtually
> mapped caches such as ARM, MIPS and SPARC.
>
> Can anyone please shed light on dax filesystem issue w.r.t ARM architecture ?

The concern is VIVT caches since the kernel will want to flush pmem
addresses with different virtual addresses than what userspace is
using. As far as I know, ARMv8 has VIPT caches, so should not have an
issue. Willy initially wrote those restrictions, but I am assuming
that the concern was managing the caches in the presence of virtual
aliases.