Re: Xen 4.18.5 PV dbregs fail

[Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>]

On Mon, May 26, 2025 at 10:56:41PM +0200, Manuel Bouyer wrote:
> On Mon, May 26, 2025 at 09:30:53PM +0100, Andrew Cooper wrote:
> > On 26/05/2025 9:13 pm, Manuel Bouyer wrote:
> > > On Mon, May 26, 2025 at 07:50:14PM +0100, Andrew Cooper wrote:
> > >> [...]
> > >> Well, that range does include the aforementioned commit.
> > >>
> > >> Can you bisect around d32c77f471fb8400b6512c171a14cdd58f04f0a3 which is
> > >> the backport of ^ in 4.18 ?
> > > Sure,
> > > with 0d5f15e and d32c77f the test pass, with cecee35 it fails.
> > >
> > 
> > Oh interesting, so the basic forwarding of #DB back into a guest
> > (d32c77f) works fine, but the changes to emulated debug exceptions
> > (cecee35) break.
> > 
> > Anyway, I think I've spotted a logical error.  We do indeed end up
> > calling x86_merge_dr6() twice, because of the TODO just out of context. 
> > Does this help?
> 
> Yes, it works for cecee35; now testing with 4.18.5

yes, it works with 4.18.5 too. All dbreg-related tests now pass again
thanks !

-- 
Manuel Bouyer <bouyer@xxxxxxxxxxxxxxx>
     NetBSD: 26 ans d'experience feront toujours la difference
--