Re: [PATCH v5 04/19] accel/tcg: Adjust probe_access call to page_check_range

[Peter Maydell]

On Fri, 8 May 2020 at 17:57, Richard Henderson
<address@hidden> wrote:
> On 5/8/20 9:13 AM, Peter Maydell wrote:
> > We've gone round this multiple times now so I feel like
> > I must be missing something here.
>
> While probe_access() has a size parameter, probe_access_flags() does not.
>
> For probe_access_internal(), I currently have a "fault_size" parameter that
> gets passed to tlb_fill, which is "size" for probe_access() and 0 for
> probe_access_flags().
>
> I *could* add another "check_size" parameter to probe_access_internal, to be
> passed on to page_check_range(). It would be "size" for probe_access() and 1
> for probe_access_flags().  But what's the point?  Always passing 1 to
> page_check_range() has the same effect.
>
> I feel like I'm missing something with your objection.

The thing I was missing was that probe_access_flags() doesn't
have a size to pass usefully to probe_access_internal() and
so the size is zero in that case, but that tlb_fill() and
probe_check_range() want different values for the "just
tell me about this address" case.

thanks
-- PMM