[PATCH v1 0/4] Fix a bug in VGIC ITS tables' save/restore

Oliver Upton oliver.upton at linux.dev
Tue Nov 5 13:58:03 PST 2024


On Tue, Nov 05, 2024 at 01:56:14PM -0800, Jing Zhang wrote:
> On Tue, Nov 5, 2024 at 1:33 PM Oliver Upton <oliver.upton at linux.dev> wrote:
> >
> > Hi Jing,
> >
> > On Tue, Nov 05, 2024 at 11:34:18AM -0800, Jing Zhang wrote:
> > > The core issue stems from the static linked list implementation of DTEs/ITEs,
> > > requiring a full table scan to locate the list head during restoration. This
> > > scan increases the likelihood of encountering orphaned entries.  To rectify
> > > this, the patch series introduces a dummy head to the list, enabling immediate
> > > access to the list head and bypassing the scan. This optimization not only
> > > resolves the bug but also significantly enhances restore performance,
> > > particularly in edge cases where valid entries reside at the end of the table.
> >
> > I think we need a more targeted fix (i.e. Kunkun's patch) to stop the
> > bleeding + backport it to stable.
> >
> > Then we can have a separate discussion about improving the save/restore
> > performance with your approach.
> 
> Yes, I'll respin Kunkun's patch soon. This patch series has the
> selftest which we can use for verification.

Right -- go ahead and include your selftest as part of that respin, I'd
definitely like to have some test coverage for this whole save/restore mess.

-- 
Thanks,
Oliver



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