[PATCH v3 3/7] mm: Add PG_arch_3 page flag

[Peter Collingbourne]

On Tue, Sep 20, 2022 at 9:58 AM Catalin Marinas <catalin.marinas at arm.com> wrote:
>
> On Tue, Sep 20, 2022 at 05:33:42PM +0100, Marc Zyngier wrote:
> > On Tue, 20 Sep 2022 16:39:47 +0100,
> > Catalin Marinas <catalin.marinas at arm.com> wrote:
> > > On Mon, Sep 19, 2022 at 07:12:53PM +0100, Marc Zyngier wrote:
> > > > On Mon, 05 Sep 2022 18:01:55 +0100,
> > > > Catalin Marinas <catalin.marinas at arm.com> wrote:
> > > > > Peter, please let me know if you want to pick this series up together
> > > > > with your other KVM patches. Otherwise I can post it separately, it's
> > > > > worth merging it on its own as it clarifies the page flag vs tag setting
> > > > > ordering.
> > > >
> > > > I'm looking at queuing this, but I'm confused by this comment. Do I
> > > > need to pick this as part of the series? Or is this an independent
> > > > thing (my hunch is that it is actually required not to break other
> > > > architectures...).
> > >
> > > This series series (at least the first patches) won't apply cleanly on
> > > top of 6.0-rc1 and, of course, we shouldn't break other architectures. I
> > > can repost the whole series but I don't have the setup to test the
> > > MAP_SHARED KVM option (unless Peter plans to post it soon).
> >
> > I don't feel brave enough to take a series affecting all architectures
>
> It shouldn't affect the others, the only change is that PG_arch_2 is now
> only defined for arm64 but no other architecture is using it. The
> problem with loongarch is that it doesn't have enough spare bits in
> page->flags and even without any patches I think it's broken with the
> right value for NR_CPUS.
>
> > so late in the game, and the whole thing had very little arm64
> > exposure. The latest QEMU doesn't seem to work anymore, so I don't
> > have any MTE-capable emulation (and using the FVP remotely is a pain
> > in the proverbial neck).
> >
> > I'll come back to this after the merge window, should Peter decide to
> > respin the series.
>
> It makes sense.

Apologies for the delay, I've now sent out v4 of this series which
includes the patches on your branch.

Peter