Re: [PATCH v8 38/45] target/arm: Complete TBI clearing for user-only for SVE

[Peter Maydell]

On Tue, 23 Jun 2020 at 20:37, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> There are a number of paths by which the TBI is still intact
> for user-only in the SVE helpers.
>
> Because we currently always set TBI for user-only, we do not
> need to pass down the actual TBI setting from above, and we
> can remove the top byte in the inner-most primitives, so that
> none are forgotten.  Moreover, this keeps the "dirty" pointer
> around at the higher levels, where we need it for any MTE checking.
>
> Since the normal case, especially for user-only, goes through
> RAM, this clearing merely adds two insns per page lookup, which
> will be completely in the noise.

Can we have an assert() somewhere suitable that TBI is set?
That way if we ever do have an SVE-capable linux-user which
doesn't set TBI for some reason we'll get a useful reminder
that we need to fix something.

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM