Re: [4.22] Re: [PATCH] x86/domctl: restore all registers in arch_{get,set}_info_guest()

["Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>]

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On Mon, Jul 20, 2026 at 10:59:00AM +0100, Frediano Ziglio wrote:
> On Mon, 20 Jul 2026 at 10:09, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> >
> > On 20/07/2026 8:19 am, Jan Beulich wrote:
> > > On 20.07.2026 02:12, Marek Marczykowski-Górecki wrote:
> > >> Commit 9f892f84c279 ("x86/domctl: Stop using XLAT_cpu_user_regs()")
> > >> converted memcpy() of the cpu_user_regs structure to explicit copy of
> > >> its fields. In the compat case, it intentionally missed few of them,
> > >> named in the commit message. But the 64bit case missed also r8-r15
> > >> registers, which was not intentional. This, at least, caused Linux
> > >> 6.18.x crash when resuming PVH domU.
> > > Oh, wow, what a bad mistake (including by me as the reviewer).
> >
> > Yes, I'm very embarrassed by this mistake.  It also highlights a serious
> > gap in testing which we need to address.  We've managed a release and a
> > half with PV migration plain broken before figuring out why.
> >
> ...
> 
> Is migration tested by CI or just for some reason this was not captured?

It was in osstest, but it isn't in gitlab. I'll cleanup my current test
and submit it, but I'd really appreciate committing the (reviewed/acked)
test-artifacts series[1], as some of the pending tests depend on it
(although the suspend one doesn't).

[1] https://lore.kernel.org/xen-devel/ah24pfWb_orPRaJG@mail-itl/

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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