Re: [PATCH 07/17] xen/x86: traps: Convert __page_fault_type() to use typesafe MFN

[Julien Grall <julien@xxxxxxx>]

On 18/04/2020 12:01, Julien Grall wrote:
> On 26/03/2020 15:54, Jan Beulich wrote:
> > On 22.03.2020 17:14, julien@xxxxxxx wrote:
> > > From: Julien Grall <jgrall@xxxxxxxxxx>
> > >
> > > Note that the code is now using cr3_to_mfn() to get the MFN. This is
> > > slightly different as the top 12-bits will now be masked.
> > And here I agree with the change. Hence it is even more so important
> > that the patch introducing the new helper(s) first gets sorted.
> > Should there be further patches in this series with this same
> > interaction issue, I won't point it out again and may not respond at
> > all if I see no other issues.
> I will update the commit message explaining the reason of using 
> cr3_to_mfn() and look at the other user.
Looking at the code again, there are a few users that don't mask the top 
12-bits. I am trying to understand why this has never been an issue so far.
Wouldn't it break when bit 63 (no flush) is set? If so, maybe I should 
split the work from typesafe.
Cheers,

--
Julien Grall